Dissertations / Theses: 'Rape (Plant)'

1

Fiebelkorn, Wrucke Danielle. "Genetic Analysis of Frost Tolerance in Rapeseed/Canola (Brassica Napus L.)." Diss., North Dakota State University, 2017. https://hdl.handle.net/10365/28362.

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Frost can be detrimental to canola (Brassica napus L.) production. Depending on the severity, the entire field can be killed. Having frost tolerance in canola would benefit growers by allowing them to plant early, utilize early season moisture, and avoid high heat during flowering. However, frost tolerance in canola has not been well studied. A protocol was developed that determined 14 day old seedlings should be acclimated at 4?C for 7 days before being exposed to overnight frost (-4?C) in a small freezing chamber. However, when a larger chamber was used for freezing, the protocol was optimized to -8?C instead. A greenhouse study was conducted on a diverse collection of 231 genotypes and genome-wide association scan (GWAS) was conducted to identify potential genes that were related to frost tolerance or abiotic stress tolerance. Thirty-eight significant single nucleotide polymorphism (SNP) markers were selected based on 10,000 bootstraps and 0.1 percent tail of the empirical distribution. The markers were located on chromosomes A01, A02, A03, A04, A07, A08, A09, A10, C03, C05, C06, C07, and C09. Stepwise regression highlighted a QTL located on chromosomes A02. Another GWAS was done on 147 canola germplasm lines phenotyped under natural conditions. Thirty-eight significant SNPs identified from this study were located on chromosomes A05, A07, A09, C01, C02, C03, C04, C05, C06, C07, and C09. Stepwise regression identified a QTL located on chromosome C04. A protocol was developed to measure the freezing induced electrolyte leakage from leaves of rapeseed/canola. A total of 157 germplasm lines were evaluated for freezing induced (-12?C for 2 h) electrolyte leakage. Thirty-six significant SNPs located on chromosomes A01, A02, A03, A04, A05, A06, A07, A08, A09, A10, C01, C02, C04, C05, C06, C07, and C09 were identified. Stepwise regression identified 10 QTL located on chromosomes A01, A02, A04, A06, A07, C02, C05, C07, C09, and one that could not be assigned. All GWAS studies identified potential genes of interest that were related to frost tolerance, abiotic stress, and transcription factors.
Northern Canola Growers Association

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2

Mulyati. "Zinc requirements of transplanted oilseed rape." Thesis, Mulyati, (2004) Zinc requirements of transplanted oilseed rape. PhD thesis, Murdoch University, 2004. https://researchrepository.murdoch.edu.au/id/eprint/213/.

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Transplanting is a common practice for many horticultural crops and some field crops. Recently, transplanted oilseed rape (Brassica napus L.) crops have been reported to be sensitive to zinc (Zn) deficiency. However, Zn nutrition in transplanted field crops has not been investigated in detail. The objectives of this present research were to investigate whether transplanting increases external Zn requirements of transplanted oilseed rape, and the mechanisms of root function, growth and Zn uptake after transplanting including rhizosphere modification capacity by plant roots. The second objective was to examine the relative effects of root pruning and transplanting on Zn responses of oilseed rape, and the third objective was to determine external and internal Zn requirements of transplanted oilseed rape for diagnosing and predicting Zn deficiency. An experiment on a low Zn sand (DTPA extractable Zn 0.14 mg kg-1) was set up to determine whether transplanted oilseed rape had a higher Zn requirement than that of direct-sown plants. Low Zn supply depressed shoot dry weight, however, root growth was relatively more strongly suppressed than shoots. Maximum root dry weight required much higher external Zn for transplanted plants compared to direct-sown plants, whilst shoot dry weight required a similarly low external Zn supply. In addition, transplanted plants were sensitive to zinc deficiency during the early post-transplanting growth, and the response weakened as the plants recovered from root injury or transplanting stress. However, the transplanted plants also experienced root pruning before transplanting and so in this experiment the higher Zn requirement could have been due to root pruning or transplanting or both. A further experiment was undertaken to determine the comparative external Zn requirements of direct-sown and transplanted plants in well-stirred chelate-buffered solution culture where a rhizosphere effect on plant availability of Zn forms is absent and the effects of poor root-soil contact on post-transplanting growth are minimized. In solution culture at the same level of Zn supplied, direct- sown plants produced higher shoot and root dry matter and greater root length than those of transplanted plants. However, since a higher external Zn requirement was found for transplanted plants in buffered solution culture than for direct- sown plants, it was concluded that the higher Zn requirement was not related to decreased rhizosphere modification, to greater demand for Zn or to poor root-solution contact, but rather to the time required for transplanted plants to recover from transplanting and root injury. The recovery of root function in solution culture was more rapid than that in soil culture and expressed as a higher Zn requirement for shoot as well as root growth. It suggested that the delay in root recovery in soil culture was due to slower absorption of Zn from the soil after transplanting than was the case in solution culture. Chelate-buffered nutrient solution culture and harvesting plants successively at 5 day intervals until 25 days after transplanting was used to examine the mechanisms of the recovery of root growth and function. In this experiment, the external Zn requirement of transplanted plants was investigated with unpruned or pruned root systems. Plants with unpruned root system and sufficient Zn supply exhibited faster recovery from transplanting than those with pruned root system plants. The results suggest that root pruning impaired Zn uptake by plant roots and slowed down the root and shoot growth after transplanting. Increased solution Zn partly alleviated the effects of root pruning and presumably this is a major reason why transplanted oilseed rape had a high external Zn requirement. However, root pruning also appeared to impair water uptake, and may have suppressed shoot growth through sequestering carbon for new root growth and through decreased phytohormone production by roots. Since rapid root recovery of transplanted plants is essential for successful of growth in the field, Zn application to the nursery bed was explored as a starter fertilizer to stimulate root growth after transplanting. The objective of this experiment was to determine whether increasing the seedbed Zn would stimulate new root growth of transplanted oilseed rape, and therefore would alleviate the need for increased external Zn for post-transplanting growth. Results showed that adequate Zn concentration in the seedbed promoted the post-transplanting growth by stimulating the new root growth especially increased root length, and also hastened the recovery of root systems. However, high Zn concentration at transplanting still had a more dominant effect in stimulating the new root growth of oilseed rape after transplanting. The final experiment was set up using rhizobags with three rates of Zn supply and unpruned or pruned root systems. The purpose of this study was to investigate the chemical change in the rhizosphere and non-rhizosphere or bulk soil and its relationship to the recovery of root function after transplanting, and also to identify and quantify the organic acids in soil extracts of direct-sown and transplanted plants. The rhizosphere soil pH was lower than that of non-rhizosphere soil, and the decrease of soil pH was suggested as the mechanism of the increase of Zn availability and mobility in the rhizosphere soil. Direct-sown plants were more efficient in utilizing Zn than those of transplanted plants especially compared to those of plants with pruned root system. Zinc deficient plants excreted higher concentration of organic acids particularly citric acid, suggesting this was a mechanism of Zn mobilization and Zn uptake by roots of oilseed rape. The main implications of the present study for the management of Zn nutrition of transplanted crops were: the need to increase the Zn application to crops in the nursery and at transplanting compared to direct-sown plants; the possibility that external requirements of other nutrients will be greater in transplanted crops also requires further consideration; and in cropping systems where transplanting is practised, greater attention should be given to the avoidance of root damage during the transplanting.

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3

Mulyati. "Zinc requirements of transplanted oilseed rape." Murdoch University, 2004. http://wwwlib.murdoch.edu.au/adt/browse/view/adt-MU20060109.135933.

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Abstract:

Transplanting is a common practice for many horticultural crops and some field crops. Recently, transplanted oilseed rape (Brassica napus L.) crops have been reported to be sensitive to zinc (Zn) deficiency. However, Zn nutrition in transplanted field crops has not been investigated in detail. The objectives of this present research were to investigate whether transplanting increases external Zn requirements of transplanted oilseed rape, and the mechanisms of root function, growth and Zn uptake after transplanting including rhizosphere modification capacity by plant roots. The second objective was to examine the relative effects of root pruning and transplanting on Zn responses of oilseed rape, and the third objective was to determine external and internal Zn requirements of transplanted oilseed rape for diagnosing and predicting Zn deficiency. An experiment on a low Zn sand (DTPA extractable Zn 0.14 mg kg-1) was set up to determine whether transplanted oilseed rape had a higher Zn requirement than that of direct-sown plants. Low Zn supply depressed shoot dry weight, however, root growth was relatively more strongly suppressed than shoots. Maximum root dry weight required much higher external Zn for transplanted plants compared to direct-sown plants, whilst shoot dry weight required a similarly low external Zn supply. In addition, transplanted plants were sensitive to zinc deficiency during the early post-transplanting growth, and the response weakened as the plants recovered from root injury or transplanting stress. However, the transplanted plants also experienced root pruning before transplanting and so in this experiment the higher Zn requirement could have been due to root pruning or transplanting or both. A further experiment was undertaken to determine the comparative external Zn requirements of direct-sown and transplanted plants in well-stirred chelate-buffered solution culture where a rhizosphere effect on plant availability of Zn forms is absent and the effects of poor root-soil contact on post-transplanting growth are minimized. In solution culture at the same level of Zn supplied, direct- sown plants produced higher shoot and root dry matter and greater root length than those of transplanted plants. However, since a higher external Zn requirement was found for transplanted plants in buffered solution culture than for direct- sown plants, it was concluded that the higher Zn requirement was not related to decreased rhizosphere modification, to greater demand for Zn or to poor root-solution contact, but rather to the time required for transplanted plants to recover from transplanting and root injury. The recovery of root function in solution culture was more rapid than that in soil culture and expressed as a higher Zn requirement for shoot as well as root growth. It suggested that the delay in root recovery in soil culture was due to slower absorption of Zn from the soil after transplanting than was the case in solution culture. Chelate-buffered nutrient solution culture and harvesting plants successively at 5 day intervals until 25 days after transplanting was used to examine the mechanisms of the recovery of root growth and function. In this experiment, the external Zn requirement of transplanted plants was investigated with unpruned or pruned root systems. Plants with unpruned root system and sufficient Zn supply exhibited faster recovery from transplanting than those with pruned root system plants. The results suggest that root pruning impaired Zn uptake by plant roots and slowed down the root and shoot growth after transplanting. Increased solution Zn partly alleviated the effects of root pruning and presumably this is a major reason why transplanted oilseed rape had a high external Zn requirement. However, root pruning also appeared to impair water uptake, and may have suppressed shoot growth through sequestering carbon for new root growth and through decreased phytohormone production by roots. Since rapid root recovery of transplanted plants is essential for successful of growth in the field, Zn application to the nursery bed was explored as a starter fertilizer to stimulate root growth after transplanting. The objective of this experiment was to determine whether increasing the seedbed Zn would stimulate new root growth of transplanted oilseed rape, and therefore would alleviate the need for increased external Zn for post-transplanting growth. Results showed that adequate Zn concentration in the seedbed promoted the post-transplanting growth by stimulating the new root growth especially increased root length, and also hastened the recovery of root systems. However, high Zn concentration at transplanting still had a more dominant effect in stimulating the new root growth of oilseed rape after transplanting. The final experiment was set up using rhizobags with three rates of Zn supply and unpruned or pruned root systems. The purpose of this study was to investigate the chemical change in the rhizosphere and non-rhizosphere or bulk soil and its relationship to the recovery of root function after transplanting, and also to identify and quantify the organic acids in soil extracts of direct-sown and transplanted plants. The rhizosphere soil pH was lower than that of non-rhizosphere soil, and the decrease of soil pH was suggested as the mechanism of the increase of Zn availability and mobility in the rhizosphere soil. Direct-sown plants were more efficient in utilizing Zn than those of transplanted plants especially compared to those of plants with pruned root system. Zinc deficient plants excreted higher concentration of organic acids particularly citric acid, suggesting this was a mechanism of Zn mobilization and Zn uptake by roots of oilseed rape. The main implications of the present study for the management of Zn nutrition of transplanted crops were: the need to increase the Zn application to crops in the nursery and at transplanting compared to direct-sown plants; the possibility that external requirements of other nutrients will be greater in transplanted crops also requires further consideration; and in cropping systems where transplanting is practised, greater attention should be given to the avoidance of root damage during the transplanting.

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4

Ye, Zhengqian. "Effect of low temperature on boron nutrition of oilseed rape and sunflower." Thesis, Ye, Zhengqian (2004) Effect of low temperature on boron nutrition of oilseed rape and sunflower. PhD thesis, Murdoch University, 2004. https://researchrepository.murdoch.edu.au/id/eprint/418/.

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Abstract:

Several reports appear in the literature linking low temperature damage in plants with boron (B) deficiency and alleviation of low temperature injury with B application has been reported in some crops and trees. These results imply that low temperature might increase plant B requirements, beside the reduction of B uptake by plant roots, or that low B tissues might be more sensitive to cold temperature damage than B adequate tissues. In controlled experiments, it has been shown that low root zone temperature (RZT) induces B deficiency in cassava, a tropical root crop. Apart from this, there are few definitive detailed investigations on low temperature effects on B nutrition of plants, including temperate species which are more tolerant of low temperature. Winter oilseed rape (Brassica napus L.), a crop sensitive to low B supply, is a major crop in the middle and lower Yangtse river basin, China, where low B soils are widespread. Appearance of B deficiency in oilseed rape often coincides with cold weather during its winter and spring growth. However, the incidence and severity of B deficiency of oilseed rape plants and the efficacy of B fertilization varies from year to year and location to location in ways that are not explained simply by differences in cultivar, agronomy or soil B levels. Low temperature is probably one of the important environmental factors influencing growth and yield of oilseed rape in relation to B nutrition. Therefore,the objective of the studies in this thesis was to investigate mechanisms of low temperature effects on B nutrition of plants with emphasis on oilseed rape. Field and glasshouse experiments were carried out and the physiological basis of plant response to B at different air and root temperatures is discussed. A field experiment with oilseed rape cv. Zheyouyou 2 was carried out on a red soil (Hapludult, US Soil Taxonomy) with low B availability in Zhejiang province, China. Canopy covers made from transparent plastic sheets, which increased night temperatures by up to 1.5 oC around shoots for 15 days in early February, strongly increased shoot dry weight at all levels of B supply. Furthermore, covering plants increased shoot dry weight of B deficient plants without increasing their leaf B concentration. This suggests that internal B requirements were decreased by canopy covering, possibly due to higher temperatures within the canopy. Experiments conducted to investigate the effect of RZT (10 and 20 oC) on oilseed rape cv. Hyola 42 response to B in solution culture, in summer and winter, showed that regardless of canopy conditions, low RZT (10 oC) promoted the distribution of shoot B towards the actively growing leaves, especially when B supply was low. At low B supply, B deficiency symptoms appeared later at 10 oC than 20 oC RZT and B concentrations in the youngest fully opened leaves (YOL) were higher in plants grown at RZT of 10 oC than that at 20 oC. Growth of plant dry weight (DW) was not affected by RZT in the summer but was greatly reduced at 10 oC than 20 oC in winter. In B adequate plants, shoot to root ratio (S/R ratio) was not affected by RZT regardless of canopy conditions. By contrast, S/R ratio was smaller in low B plants at 10 oC than 20 oC. In addition, low RZT delayed occurrence of plant B deficiency symptoms regardless of plants' pre-treatment RZT (either 10 or 20 oC). These results appeared to contradict the response to low RZT found in previous studies with cassava. In a subsequent experiment, low RZT of 5 oC not only greatly reduced plant DW production of oilseed rape, but also accentuated plant B deficiency. Partitioning of B into the young growing shoots was also depressed and a significant decrease of B concentration in the youngest shoot parts was caused by 5 oC RZT in comparison with that at the control RZT (10 oC). Similar results were also observed in sunflower (Helianthus annuus L. cv. Hysun 25). But B deficiency symptoms in sunflower were induced by RZT as high as 12 oC, when plants were supplied with 0.25 mcg B, whilst these plants were free from B deficiency at warmer RZT (17 - 27 oC). Higher external B concentrations were required at such RZT (Chilling temperature) for plant growth free from B deficiency. Therefore, there is a RZT threshold below which an increased response to B is expected in plants of oilseed rape and sunflower. And in the range of chilling RZT, the external B requirement for shoot growth increased with lower RZT. The threshold RZT was considerably higher in the chilling-sensitive plant species, sunflower, than in oilseed rape, a chilling-resistant plant species. At chilling RZT, leaf functioning was impaired by low B supply as measured by potassium (K) leakage from the youngest mature leaf blade (YML) of sunflower, whereas it was much less directly affected by RZT, and there was no effect of RZT on B- adequate plants. By contrast to leaves, root function was impaired more by chilling RZT than low B. Despite their different threshold RZT, in both oilseed rape and sunflower, the rates of B uptake (BUR) and B translocation from root to shoot (BTR) were dramatically depressed by chilling RZT especially at low B supply (0.2 mcg B): being only 30% of those at the control (5 oC vs 10 oC RZT) in oilseed rape and 33% (10 oC vs 20 oC RZT) in sunflower, respectively. By contrast, there was little or no difference over a range of warmer RZT (10 - 20 oC for oilseed rape, and 20 - 27 oC for sunflower). It is predicted that higher rates of B application will be required for plant growth when soil temperature is below a critical threshold, which is between 5 and 10 oC for oilseed rape, and about 17 oC for sunflower, respectively. Below the threshold RZT plant B deficiency was induced and accentuated due to impairment of B translocation into growing shoot parts besides the decrease of B uptake rate and B transport rate and greater shoot to root ratio. In comparison with RZT, little is known about causal mechanisms linking cold air temperature and B nutrition. Experiments in this thesis showed not only B transport to the shoot was strongly reduced by low night air temperature during a 6 day period (11.719.4 vs 15.5 - 23.5 oC), but also that an overnight chilling (at 0 oC) could cause more severe injury to low B than adequate B leaves of oilseed rape plants, expressed by higher solute leakage, in comparison with control (at 10 oC). Moreover, after chilling treatment, solute leakage from low B leaves was increased by exposure to light, which suggests that low temperature injury to leaves in low B plants after a freezing night in the field is at least partly a consequence of light induced damage of leaves. In summary, at chilling temperature, B uptake, transport and partitioning into growing shoots are strongly impaired, and B use efficiency in the growing tissues might be reduced as well. Low temperature contributes to plant B deficiency also by increasing S/R ratio, so that shoot B demand is not satisfied by available B. Furthermore, low air temperature might increase the internal B requirement for shoot growth. To further understand mechanisms of low temperature, especially the air temperature, effects on plant responses to B, more research is needed, such as the relationship between low temperature and B incorporation into cell walls which may play an important role in leaf tolerance to chilling temperature.

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5

Ye, Zhengqian. "Effect of low temperature on boron nutrition of oilseed rape and sunflower." Murdoch University, 2004. http://wwwlib.murdoch.edu.au/adt/browse/view/adt-MU20060510.154332.

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Abstract:

Several reports appear in the literature linking low temperature damage in plants with boron (B) deficiency and alleviation of low temperature injury with B application has been reported in some crops and trees. These results imply that low temperature might increase plant B requirements, beside the reduction of B uptake by plant roots, or that low B tissues might be more sensitive to cold temperature damage than B adequate tissues. In controlled experiments, it has been shown that low root zone temperature (RZT) induces B deficiency in cassava, a tropical root crop. Apart from this, there are few definitive detailed investigations on low temperature effects on B nutrition of plants, including temperate species which are more tolerant of low temperature. Winter oilseed rape (Brassica napus L.), a crop sensitive to low B supply, is a major crop in the middle and lower Yangtse river basin, China, where low B soils are widespread. Appearance of B deficiency in oilseed rape often coincides with cold weather during its winter and spring growth. However, the incidence and severity of B deficiency of oilseed rape plants and the efficacy of B fertilization varies from year to year and location to location in ways that are not explained simply by differences in cultivar, agronomy or soil B levels. Low temperature is probably one of the important environmental factors influencing growth and yield of oilseed rape in relation to B nutrition. Therefore,the objective of the studies in this thesis was to investigate mechanisms of low temperature effects on B nutrition of plants with emphasis on oilseed rape. Field and glasshouse experiments were carried out and the physiological basis of plant response to B at different air and root temperatures is discussed. A field experiment with oilseed rape cv. Zheyouyou 2 was carried out on a red soil (Hapludult, US Soil Taxonomy) with low B availability in Zhejiang province, China. Canopy covers made from transparent plastic sheets, which increased night temperatures by up to 1.5 oC around shoots for 15 days in early February, strongly increased shoot dry weight at all levels of B supply. Furthermore, covering plants increased shoot dry weight of B deficient plants without increasing their leaf B concentration. This suggests that internal B requirements were decreased by canopy covering, possibly due to higher temperatures within the canopy. Experiments conducted to investigate the effect of RZT (10 and 20n oC) on oilseed rape cv. Hyola 42 response to B in solution culture, in summer and winter, showed that regardless of canopy conditions, low RZT (10 oC) promoted the distribution of shoot B towards the actively growing leaves, especially when B supply was low. At low B supply, B deficiency symptoms appeared later at 10 oC than 20 oC RZT and B concentrations in the youngest fully opened leaves (YOL) were higher in plants grown at RZT of 10 oC than that at 20 oC. Growth of plant dry weight (DW) was not affected by RZT in the summer but was greatly reduced at 10 oC than 20 oC in winter. In B adequate plants, shoot to root ratio (S/R ratio) was not affected by RZT regardless of canopy conditions. By contrast, S/R ratio was smaller in low B plants at 10 oC than 20 oC. In addition, low RZT delayed occurrence of plant B deficiency symptoms regardless of plants¡¦ pre-treatment RZT (either 10 or 20 oC). These results appeared to contradict the response to low RZT found in previous studies with cassava. In a subsequent experiment, low RZT of 5 oC not only greatly reduced plant DW production of oilseed rape, but also accentuated plant B deficiency. Partitioning of B into the young growing shoots was also depressed and a significant decrease of B concentration in the youngest shoot parts was caused by 5 oC RZT in comparison with that at the control RZT (10 oC). Similar results were also observed in sunflower (Helianthus annuus L. cv. Hysun 25). But B deficiency symptoms in sunflower were induced by RZT as high as 12 oC, when plants were supplied with 0.25 £gM B, whilst these plants were free from B deficiency at warmer RZT (17 - 27 oC). Higher external B concentrations were required at such RZT (Chilling temperature) for plant growth free from B deficiency. Therefore, there is a RZT threshold below which an increased response to B is expected in plants of oilseed rape and sunflower. And in the range of chilling RZT, the external B requirement for shoot growth increased with lower RZT. The threshold RZT was considerably higher in the chilling-sensitive plant species, sunflower, than in oilseed rape, a chilling-resistant plant species. At chilling RZT, leaf functioning was impaired by low B supply as measured by potassium (K) leakage from the youngest mature leaf blade (YML) of sunflower, whereas it was much less directly affected by RZT, and there was no effect of RZT on B- adequate plants. By contrast to leaves, root function was impaired more by chilling RZT than low B. Despite their different threshold RZT, in both oilseed rape and sunflower, the rates of B uptake (BUR) and B translocation from root to shoot (BTR) were dramatically depressed by chilling RZT especially at low B supply (0.2 £gM B): being only 30% of those at the control (5 oC vs 10 oC RZT) in oilseed rape and 33% (10 oC vs 20 oC RZT) in sunflower, respectively. By contrast, there was little or no difference over a range of warmer RZT (10 - 20 oC for oilseed rape, and 20 ¡V 27 oC for sunflower). It is predicted that higher rates of B application will be required for plant growth when soil temperature is below a critical threshold, which is between 5 and 10 oC for oilseed rape, and about 17 oC for sunflower, respectively. Below the threshold RZT plant B deficiency was induced and accentuated due to impairment of B translocation into growing shoot parts besides the decrease of B uptake rate and B transport rate and greater shoot to root ratio. In comparison with RZT, little is known about causal mechanisms linking cold air temperature and B nutrition. Experiments in this thesis showed not only B transport to the shoot was strongly reduced by low night air temperature during a 6 day period (11.719.4 vs 15.5 ¡V 23.5 oC), but also that an overnight chilling (at 0 oC) could cause more severe injury to low B than adequate B leaves of oilseed rape plants, expressed by higher solute leakage, in comparison with control (at 10 oC). Moreover, after chilling treatment, solute leakage from low B leaves was increased by exposure to light, which suggests that low temperature injury to leaves in low B plants after a freezing night in the field is at least partly a consequence of light induced damage of leaves. In summary, at chilling temperature, B uptake, transport and partitioning into growing shoots are strongly impaired, and B use efficiency in the growing tissues might be reduced as well. Low temperature contributes to plant B deficiency also by increasing S/R ratio, so that shoot B demand is not satisfied by available B. Furthermore, low air temperature might increase the internal B requirement for shoot growth. To further understand mechanisms of low temperature, especially the air temperature, effects on plant responses to B, more research is needed, such as the relationship between low temperature and B incorporation into cell walls which may play an important role in leaf tolerance to chilling temperature.

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6

Stangoulis, James Constantine Roy. "Genotypic variation in oilseed rape to low boron nutrition and the mechanism of boron efficiency." Title page, contents and summary only, 1998. http://web4.library.adelaide.edu.au/theses/09PH/09phs7856.pdf.

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Bibliography: leaves 132-159. Boron efficiency in oilseed rape (Brassica napua L. and B. juncea L.) was investigated in a wide range of genotypes. Using a solution culture screening of 10 day old seedlings, root length best described shoot growth response, and was used to characterise a total of 65 genotypes. Varieties and breeders lines tolerant of B-deficient growing conditions were identified, and the screening process validated through field trials. B responses in plants sampled at the 'green bud' stage indicated that vegetative growth is important in B efficiency. Studies were conducted to investigate the mechanism of B efficiency in oilseed rape. Results suggest no association between B efficiency and the capacity to acidify the root rhizosphere, or an increased translocation of B from root to shoot. Boron retranslocation was also studied as a mechanism of B efficiency.

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Babwah, Andy Videsh. "Development and application of biotechnological tools in the major crop plant, Brassica napus." Thesis, McGill University, 2001. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=37867.

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A two-component transposable element system consisting of a stabilized Activator (Acst) and a chimeric Dissociation (Ds) element has been introduced into the genome of Brassica napus. This Acst/ Ds system incorporates the use of several highly effective screenable and selectable markers. One of these markers is the maize Lc gene, a transcriptional regulator of flavonoid biosynthetic genes. This substrate-independent screenable marker was tested for the first time in B. napus and I show that when overexpressed, there is augmented trichome production and a light-dependent, enhanced accumulation of anthocyanins in B. napus plants. The phenotypes are expressed under a wide range of conditions, are visually distinct, and are observed throughout plant development. When used as a visual marker for the Acst element, Lc B. napus plants were rapidly identified among F2 segregating populations. As part of my goal to develop a very efficient Acst/Ds system for use in B. napus, a conditional negative selectable marker, the E. coli codA gene, was also tested for the first time in B. napus. This was done because use of a substrate-dependent negative selectable marker can facilitate the rapid and reliable identification of stable Ds transposition events when used as a marker for the Acst T-DNA. The enzyme cytosine deaminase, encoded by the codA gene, catalyzes the deamination of the non-toxic compound 5-fluorocytosine (5-FC) to the highly toxic compound 5-fluorouracil. In codA transformed B. napus seedlings, expression of cytosine deaminase results in a severe suppression of growth and this phenotype is dependent on the presence of the 5-FC substrate. Wild-type seedlings, however, lack endogenous cytosine deaminase activity and appear unaffected by the presence of 5-FC in the growth media. These results indicate that codA has the potential to be used effectively in B. napus as a substrate-dependent negative selectable marker for the Acst T-DNA. To determine if Ac transposase cou

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Basu, Krishna Rachel. "Improving seed quality in winter oilseed rape." Thesis, University of Nottingham, 2003. http://eprints.nottingham.ac.uk/31239/.

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The majority of UK oilseed rape (Brassica napus L.) is September-sown on heavy clay soils where straw has been incorporated following the cereal harvest in August. A series of germination, emergence and field experiments was conducted to assess the effects of variation in seed quality on establishment and to evaluate the improvements possible by mother crop nitrogen management and pre-sowing seed treatments on commercial and farm-saved seedlots. In germination experiments designed to examme the performance of commercial seed lots at temperatures ranging between 5 and 25°C significant differences were recorded in the speed and unifonnity of germination, particularly at 10 and 15°C, which are comparable to UK field temperatures in late-August to September. The analysis of Apex variety seeds grown from nitrogen-managed mother crops in 1996 and 1998 showed a negative correlation between their nitrogen and oil percentage, which was significantly affected by both the amount (kg ha -1) and timing (vegetative growth period or flowering period) of nitrogen application. The highest nitrogen seeds were produced from mother crops that had received medium (160 kg ha -1) amounts of nitrogen fertiliser during the flowering period. Seeds that were harvested from pods taken from the lower < 1.5 m) section of the crop canopy also had a significantly higher nitrogen and significantly lower oil percentage than those taken from the upper (> 1.5 m) section of the canopy. In germination and emergence experiments the highest nitrogen (3.46 to 3.61 %) seeds germinated significantly faster than the seeds of lowest nitrogen (2.30 to 2.95%) content but they did not emerge as well as low nitrogen seeds from depth. Selecting small (< 2 mm diameter) seeds over large (> 2 mm diameter) seeds significantly improved the rate of geTI11ination and emergence and the final percentage emergence at 10 mm sowing depth although the final percentage emergence at 20 mm sowing depth was significantly greater from the large seeds. Hydrating seeds in water for 18 hours at 15 grad. C before drying them back in the laboratory at 20 grad. C significantly improved the speed of germination and the speed and final percentage emergence at 10 mm sowing depth compared with control treatments provided that the radicle had not emerged before drying back; small seeds derived the most benefit from hydration. Seed heat treatment at temperatures of 80 grad. C significantly delayed the onset of germination and emergence but significantly hastened field establishment. The effects of seed nitrogen percentage, seed size and heat treatment on seedling emergence and subsequent plant growth and development were examined in the field between October 1999 and July 2000. Growth analyses, which were performed in February (growth phase), May (flowering) and July (pre-harvest), showed that the high nitrogen, large seeded and heat-treated populations had a significantly lower rate of plant loss than the low nitrogen, small seeded and control populations. Under field conditions, the higher growth rates and growth parameters of the seedlings produced from the high nitrogen and! or large seeds were not always significant nor were they consistently maintained until harvest. Large seed size and heat treatment significantly increased the number of established plants per m2 and significantly increased the initial plant size. The final yield was not significantly affected by seed nitrogen percentage, seed size or seed heat treatment.

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9

Jean, Martine. "Genetic mapping of restorer genes for cytoplasmic male sterility in Brassica napus using DNA markers." Thesis, McGill University, 1995. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=40147.

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DNA markers tightly-linked to nuclear fertility restorer genes for cytoplasmic male sterility (CMS) are valuable tools for breeders and researchers working with these genes. Two different targeting approaches were used to identify markers linked to the Rfp1 restorer gene for the pol CMS of canola (Brassica napus L.): nearly isogenic line (NIL) comparison and bulked segregant analysis. These methods were equally efficient in identifying markers linked to Rfp1; combining them allowed a targeting efficiency of 100% to be achieved. The efficiency of bulked segregant analysis was found to be limited by the inadvertent occurrence of shared homozygosity at specific chromosomal regions in the bulks, in contrast with the efficiency of NIL comparison which was limited by the occurrence of residual DNA from the donor cultivar at scattered sites around the genome of the NILs. Eleven DNA markers linked to the Rfp1 gene were identified, one of which perfectly co-segregates with Rfp1. The linkage group on which Rfp1 is localized contains 17 DNA markers. Two restorer genes of the pol CMS, Rfp1 and Rfp2, and a Rfn restorer gene of the nap CMS were found to be at least tightly linked to one another and may all reside at the same locus. A fourth restorer gene, the Rfo restorer for the ogu CMS, was, however, found to be unlinked to the other restorer genes. Different restorer genes for the nap CMS were found in the lines 'Westar-Rf and 'Karat'. A linkage map of the B. napus genome containing 146 markers organized into 23 linkage groups covering a total length of 850.2 cM was constructed from a BC$ sb1$ population. This map contains 63 loci previously localized on the B. napus genome through analysis of an F$ sb2$ population. Comparative analysis indicates that the total length of the BC$ sb1$-derived map is smaller than that of the F$ sb2$-derived map, which suggests that a reduction in recombination frequency is occurring in male gametes. The preferential use of two or three probe-

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10

McWilliam, Simon Charles. "Plant establishment, canopy structure and yield formation in oilseed rape." Thesis, University of Nottingham, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.243684.

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11

Simms, Louise Catherine. "Seed treatments to control slug damage in oilseed rape and wheat." Thesis, Available from the University of Aberdeen Library and Historic Collections Digital Resources, 2009. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?application=DIGITOOL-3&owner=resourcediscovery&custom_att_2=simple_viewer&pid=58969.

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12

Pollock, Stephanie. "A study of genetic diversity and genome organization of Brassica napus using EST (expressed sequence tags) of Arabidopsis and SSR (simple sequence repeat) markers of B. napus /." Thesis, McGill University, 2001. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=33023.

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Arabidopsis expressed sequence tags (ESTs) and microsatellites of Brassica napus have been developed and used as PCR-based markers for both mapping and genetic diversity studies in B. napus . Out of 300 random Arabidopsis ESTs screened, 43 markers were mapped onto a genetic map of B. napus and then used in a diversity study involving 48 B. napus cultivars. A second set of EST markers were developed from chromosome 1 of Arabidopsis and used in genetic mapping studies of B. napus. From 192 primer pairs developed, 50 markers were added onto the B. napus reference map. Microsatellite markers were developed using a "GA" enriched genomic library from B. napus. From 152 designed primer pairs, 23 markers were added onto the B. napus reference map. Microsatellite markers were also used in genetic diversity studies of B. napus, where, from the 152 primer pairs, 40 revealed polymorphism between the 48 B. napus cultivars.

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13

Hamel, Nancy. "Nuclear regulation of mitochondrial gene expression in Brassica napus." Thesis, McGill University, 1996. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=27331.

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Previous studies have shown that transcriptional differences in the orf224-atp6 mitochondrial gene region are correlated with fertility restoration of the pol CMS trait by the dominant nuclear Rfp gene in Brassica napus. Recently, the recessive rfp allele, or a tightly linked gene, was found to act as a dominant gene, designated Mmt, in controlling the production of additional, smaller transcripts of two other mitochondrial loci. The results presented in this thesis reveal that Mmt-specific transcripts lack sequences found at the $5 sp prime$ end of the full-length transcripts of these loci and contain a common sequence, UUGUGG, which maps immediately downstream of their $5 sp prime$ termini. A similar sequence, UUGUUG, is found within orf224 downstream of the major Rfp-specific $5 sp prime$ transcript terminus; these hexanucleotide sequences may serve as recognition motifs in the generation of Mmt- and Rfp-specific transcripts. These results suggest that Rfp/Mmt is a novel nuclear locus affecting the expression of multiple mitochondrial gene regions, with different alleles or haplotypes affecting different mitochondrial genes.

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14

Burlakoti, Pragyan. "Inoculation Techniques, Development of Brassica Napus Breeding Lines and Identification of Markers Associated with Resistance to Sclerotinia Sclerotiorum (Lib.) De Bary." Diss., North Dakota State University, 2012. https://hdl.handle.net/10365/26561.

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Sclerotinia stem rot caused by Sclerotinia sclerotiorum (Lib.) de Bary is an economic disease affecting canola (Brassica napus L). Since expression of sclerotinia stem rot symptoms shows much variability and the trait is quantitative in nature, reliable phenotypic evaluation methods for characterization are needed. The three major objectives of this dissertation were to: i) evaluate eight different inoculation methods to discriminate between S. sclerotiorum-resistant and susceptible B. napus germplasm; ii) develop breeding lines with resistance to multiple diseases, and; iii) to identify QTL associated with resistance to sclerotinia stem rot using association mapping (AM). The eight methods evaluated were the detached leaves, detached stems, petiole inoculation (PIT), straw-inoculation, stem-piercing with toothpick, mycelial spray (MSI), petal inoculation and oxalic acid assay. MSI and PIT can better discriminate between the isolates and germplasm. Breeding lines resistance to S. sclerotiorum, Leptosphaeria maculans, and Rhizoctonia solani were developed from a cross between two moderately sclerotinia stem rot resistant plant introductions (PI). F2 seedlings were screened for sclerotinia stem rot using PIT. Surviving plants were self pollinated and their progeny screened again. This process was repeated until the F6 generation. In addition, F5 seedlings were evaluated for their reaction to R. solani and F5 and F6 seedlings for their reaction to L. maculans. Eight lines were identified as moderately resistance to these three pathogens. The genomes of a group of 278 B. napus plant introductions were screened using Diversity Array Technology to detect QTL associated with resistance to sclerotinia stem rot. The population was classified into nine sub-populations and 32 significant markers each explaining between 1.5 and 4.6% of the variation were identified. Blastn search indicates that similar nucleotide sequences are distributed throughout the genomes of B. oleracea, B. rapa, and A. thaliana. Results of these studies suggest the PIT and MSI are reliable screening tools to evaluate materials for resistance to sclerotinia stem rot; materials identified as resistant to S. sclerotiorum were also moderately resistant against R. solani and L. maculans and could be valuable sources for canola improvement programs; and AM allowed us to identify QTL associated with resistance to sclerotinia stem rot.

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15

Mahe, Laetitia. "Import of chimeric proteins into plant mitochondria." Thesis, McGill University, 2001. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=33804.

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Cytoplasmic male sterility (CMS) in plants is associated with mitochondrial dysfunction. We have proposed in this study that the mitochondrial-encoded chimeric peptide thought to be responsible for cytoplasmic male sterility in Polima system could function as a dominant male sterility inducer when expressed in the nucleus and targeted to the mitochondria. Transgenic plants expressing such mitochondrial targeting constructs exhibited reduction of pollen production that was characterized in fertile Westar (nap ) and restored fertile Westar (pol) plants by homeotic transformation of floral organs and in male-sterile Westar (pol) plants by a reduction in pollen production with shortening of the stamens. Genetic and molecular analysis has shown that the phenotypic changes were correlated with the effective genetic transmission of the inserted transgene through female gametes. Most significantly, we have found that differences in floral morphology induced by transgene expression between pol CMS and fertile Westar plants might be related to differences in transcriptional activity of the APETALA3 MADS box gene. We suggest that the alterations in floral morphology that accompany CMS in several plant species might be due to effects of mitochondria on transcriptional activity of floral organ identity genes.

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16

Castillo-Ruiz, Priscila. "Plant activation of different chemicals by tobacco and brassica cell cultures, using the plant cellmicrobe coincubation assay." Thesis, McGill University, 1990. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=39239.

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In this study, the ability of various chemicals to be biotransformed into mutagens by plant cells was investigated. Two thiocarbamate herbicides, diallate and triallate, the sulfonylurea herbicide chlorsulfuron, and the aniline derivative m-phenylenediamine were tested for their ability to revert Salmonella typhimurium (strains TA100 and TA98) in the presence and absence of Nicotiana tabacum (TX1) cell cultures in liquid suspension. Chlorsulfuron and m-phenylenediamine were also tested in the presence and absence of Brassica napus cv. 'Topas' cells. Diallate was found to be activated by TX1 cells into a mutagen that induces base-pair substitution mutations. In the presence of the TX1 plant cell line, chlorsulfuron significantly increased the number of mutations on the strain TA98 of Salmonella. Tobacco TX1 cells did not activate triallate into a mutagen. m-Phenylenediamine was activated into a mutagen by TX1 and Brassica cells as detected by Salmonella TA98. This aniline derivative, in the absence of plant cells and at concentrations higher than 20 $ mu$ Moles/plate, was also able to significantly increase the number of TA98 revertants as compared to the control plants. Finally, Brassica napus cells activated chlorsulfuron into a mutagen that induces frameshift mutations.

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17

Schelfhout, Christopher James. "DNA marker assisted breeding in interspecific crosses to improve canola (Brassica napus L.)." University of Western Australia. School of Plant Biology, 2008. http://theses.library.uwa.edu.au/adt-WU2008.0167.

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[Truncated abstract] In order to expand the gene pool of canola-quality rapeseed (Brassica napus) reciprocal interspecific crosses were made between B. napus cv. Mystic and near canola-quality B. juncea breeding line JN29. F1 progeny from these crosses were used to make backcrosses to both parents in all possible combinations and directions, and were selfed to form F2-derived lines. The highest frequencies of viable F2 and BC1 progeny were obtained when B. napus was the maternal parent of the interspecific hybrid. BC1 and F2 progeny (and subsequent generations) were grown under field conditions to identify agronomic improvements over the parents. Transgressive segregation was observed in F2 and BC1 and in subsequent generations for agronomic traits (seed yield under high or low rainfall conditions, plant biomass, harvest index, height, branching and days to anthesis) and seed quality traits (oil, protein, glucosinolates, oleic acid). The majority of progeny conformed to B. napus morphology, and a minority segregated to B. juncea morphology in subsequent generations. Some of the B. juncea morphotypes had lower glucosinolates and higher oleic acid than the parent JN29, with no detectable erucic acid, and thereby conformed to canola quality. Methods were developed for tracing B-genome in interspecific progeny. A repetitive DNA sequence pBNBH35 from B. nigra (genome BB, 2n = 16) was used to identify B-genome chromosomes and introgressions in interspecific progeny. Specific primers were designed for pBNBH35 in order to amplify the repetitive sequence by PCR. A cloned sub-fragment of 329 bp was confirmed by sequencing as part of pBNBH35. PCR and hybridisation techniques were used on an array of Brassica species to confirm that the pBNBH35 subfragment was Brassica B-genome specific. Fluorescence in situ hybridisation (FISH) in B nigra, B. juncea (AABB, 2n=36) and B. napus (AACC, 2n=38) showed that the pBNBH35 sub-fragment was present on all eight Brassica Bgenome chromosomes and absent from A- and C-genome chromosomes. The pBNBH35 repeat was localised to the centromeric region of each B-genome chromosome. FISH clearly distinguished the B-genome chromosomes from the A-genome chromosomes in the amphidiploid species B. juncea. This is the first known report of a B-genome repetitive marker that is present on all Brassica Bgenome chromosomes. ... The results suggest that novel B. napus genotypes have been generated containing introgressions of B-genome chromatin from B. juncea chromosomes. B. juncea morphology occurred in interspecific progeny with a chromosome complement similar to B. napus (2n = 38) and without the entire Bgenome present. It also is highly likely that recombination has occurred between the A-genome of the two Brassica species. This research has demonstrated that the secondary gene pool of B. napus may be accessed by selfing interspecific hybrids, and without sacrificing canola quality, if the B. juncea parent is near canola-quality. Interspecific progeny may be screened to enhance the proportion with B-genome positive signals. Some progeny with B. junceatype morphology had improved seed quality over the JN29 parent.

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18

Stafford, Judith Anne. "The effects of prochloraz on the growth and yield of oilseed rape." Thesis, University of Nottingham, 1996. http://eprints.nottingham.ac.uk/12535/.

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Yield production was investigated in the winter oilseed rape variety Capricorn by comparing crops grown under standard husbandry conditions in three seasons (1991, 1992 and 1993 harvest years). Also investigated were the effects of the phytotonic imidazole fungicide prochloraz on the physiology of yield production. Prochloraz was applied in autumn, spring and summer in all possible combinations (eight treatments), except in the second season (1992), when the autumn application was omitted. Crop growth and development were studied in detail using stratified sampling in 20 cm layers. Detailed growth analysis between flowering and final harvest was restricted to untreated controls and plots receiving all three prochloraz applications. Solar radiation interception was measured using tube solarimeters arranged to correspond with layers of the profile obtained in sampling. The qualitative pattern of growth and development was the same in all three seasons regardless of variations in environmental conditions, and could be divided into the four distinct but overlapping stages described in previous studies. Potential yield (pod number) was determined at flowering and was almost constant between seasons. It did not limit final yield and can never be fully realised. Final seed yield was dependent upon the amount of solar radiation intercepted in Stage IV (seed development), and was manifested in the extent of pod and seed losses and seed growth during this period. The efficiency of radiation use varied between seasons. The main role of leaves was the development of the reproductive framework, and rapid leaf senescence occurred at flowering, particularly in Stage III (pod development). Losses of potential pods and seeds were continuous from flowering onwards but were severe in Stage III. Pod retention was determined by the availability of assimilates which depended on radiation interception and intra-plant competition for assimilates. Regulation of this was probably under hormonal control. Dry matter production was unaffected by the flower canopy except when radiation levels were unusually low during Stage III. Final yield was not affected by such effects. Seed number per pod is determined genetically, but modified during development by assimilate availability according to position in the canopy and the number of competing pods. Seed growth occurred mainly in Stage IV and depended upon the extent of photosynthesis, largely in pods and branches. Seed yield was independent of growth up to flowering, and no remobilisation of dry matter occurred to support seed-filling. When open canopies were produced, leaf retention (largely at the base of the pod canopy), radiation interception by leaf, and therefore, assimilation by leaf, were all increased. Under such circumstances, assimilate production by leaf at the base of the pod canopy may have contributed up to 20% of the dry matter (seed) produced in Stage IV. Pod and seed retention were improved throughout, but particularly higher in the canopy, because seeds that were growing well were more likely to be retained. Disease development in all treatments was monitored using detailed assessments throughout each season. The main fungicidal effects of prochloraz were on light leaf and pod spot and stem canker. Disease incidence was reduced in all seasons, but severity was reduced only in 1993. However, disease severities were generally very low, and these fungicidal effects probably had little or no effect on yield. Large losses of potential yield were caused by severe sclerotinia infection combined with high temperatures, a high soil moisture deficit, and possibly lodging (1992). Sclerotinia was controlled by iprodione in 1993. Disease data were used to form a model to estimate the expected yield losses caused by sclerotinia infection. Heavy infections of stem canker in 1993 did not seriously affect yield. Prochloraz increased seed yield by up to 16% in 1991 through increased pod numbers largely in the upper and middle regions of the pod canopy. Seed number per pod was increased slightly, largely due to higher retention in lower pods, while 1000-seed weight was not affected. Effects were negative in 1992 and inconclusive in 1993. Prochloraz increased crop growth from March onwards in 1991, and the differences in green area and dry matter components were maintained to final harvest. There was no effect on harvest index. Leaf senescence was delayed by prochloraz so that during Stage IV (seed development), leaf area index in the pod canopy and just below was greater in treated plots, and the proportion of radiation intercepted by leaf was slightly increased. Total radiation interception was increased due to the increased green area index mainly due to increased pod and stem areas in the top and middle of the canopy. Prochloraz delayed crop senescence and therefore reduced the decline in efficiency in late Stage IV. Total assimilate production in Stage IV was increased partly because of continued assimilate production for longer in all organs including retained leaf. This enabled more pods to be supported throughout the canopy. By prolonging assimilatory activity in the organs at the base of the canopy, prochloraz probably modified the pattern of assimilate movement between layers of the canopy. Seed numbers per pod in lower pods and pods higher in the canopy would, therefore, have been maintained. Reasons for the failure of prochloraz to elicit a similar response in 1992 and 1993, and the nature of the phytotonic effect are discussed. The findings are discussed in relation to the development of an oilseed rape ideotype for maximising yield production.

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19

Dharmaratne, Sumedha. "Studies on self-incompatibility in Brassica napus." Thesis, University of St Andrews, 1990. http://hdl.handle.net/10023/14131.

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A detailed investigation was conducted on the self-incompatibility system operating in the amphidiploid species, Brassica napus. Seven synthetic B. napus lines were produced by intercrossing plants of the parental species B. campestris and B. oleracea and doubling the chromosome numbers of the F1 hybrids, so formed. Each of the parental lines used in the synthesis were homozygous for different S-alleles. B. oleracea parental lines were homozygous for S29, S14 and S2 while the B. campestris line was homozygous for Sa and Sb. Consequently, the synthetic lines of B. napus were homozygous for different alleles at each of two S-loci. Following synthesis, S-allele activity and expression was examined in the synthetics and their F1's and F2's, using genetical and biochemical methods. In addition, a study of interspecific incompatibility between B. napus and B. oleracea was conducted. It was established that the production of synthetic B. napus by ovary culture in B. campestris was more successful than production using embryo culture in B. oleracea. Amphidiploid B. napus plants produced from F1 hybrids by chromosome doubling were easily identified, exhibiting a typical B. napus morphology, producing fertile buds and reflecting B. campestris and B. oleracea isozyme banding patterns. Synthetic B. napus plants were generally self-incompatible and the self-incompatibility alleles of both B. oleracea and B. campestris were expressed and showed interlocus epistasis similar to that found in a single locus sporophytic system. Several F1 lines produced from crosses between B. napus synthetics expressed only 3 alleles in any S-allele combination, and this expression occurred only in the pistils. The B. campestris alleles were functional in F1 stigmas but not in the pollen, showing that allele activity in F1 pollen would appear to be equivalent to that of a single locus system. In the F2 generation, all 4 S-alleles were active in a given genotype and it was established, therefore, that hidden S-loci could persist in a species with a sporophytic self-incompatibility system if alleles were partially or completely recessive. Test crosses between B. campestris, B. oleracea and B. napus showed that pollen from B. oleracea usually failed to penetrate the stigmatic surface of B. napus, despite all other combinations of interspecific crosses being compatible. It was found that this interspecific incompatibility could be overcome by bud pollinations or by treatment with cycloheximide. Biochemical studies showed that stigma-specific proteins, resolved by isoelectric focusing, correlated with some S-allele expression and could be detected in synthetic B. napus. However, stigma-specific proteins, which correlated with the presence of the Sa and S14 alleles, were detected in stigmas of F2 plants even when they were not active, indicating that S-protein expression is not correlated with the full function of self-incompatibility alleles.

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20

Evans, Kenneth Andrew. "The role of secondary plant metabolites in host-plant location by insect pests of oilseed rape (Brassica napus L.)." Thesis, University of Hertfordshire, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.293059.

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21

Menassa, Rima. "Nuclear-mitochondrial gene interactions and mitochondrial gene expression in Brassica napus." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape10/PQDD_0018/NQ44513.pdf.

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22

Andreasson, Erik. "Structural and functional studies of the myrosinase-glucosinolate system in Arabidopsis thaliana and Brassica napus /." Uppsala : Swedish University of Agricultural Sciences, 2000. http://bvbr.bib-bvb.de:8991/F?func=service&doc_library=BVB01&doc_number=009004668&line_number=0001&func_code=DB_RECORDS&service_type=MEDIA.

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23

Davoren, Jonathan M., and University of Lethbridge Faculty of Arts and Science. "Gene expression in a microspore-derived cell suspension culture of Brassica Napus exhibiting enhanced oil production." Thesis, Lethbridge, Alta. : University of Lethbridge, Faculty of Arts and Science, 1997, 1997. http://hdl.handle.net/10133/345.

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Triacylglycerol (TAG) production in the microspore derived (MD) cell suspension culture ofBrassica napus L. cv Jet Neuf was enhanced when the sucrose concentration in the growth medium was increased from 2 to 14 % (w/v). mRNA differential display by polymerase chain reaction was used to examine gene expression in cells grown at different sucrose concentrations in order to identify mRNAs which could be associated with oil formation. The anchored primer, T12AA, was used to screen one subset, representing approximately one twelfth of the transcript population, isolated from cultures grown in media supplemented to 2, 6 and 14 % (w/v) sucrose. Analysis of this mRNA subset revealed thirteen cDNAs which appeared to be upregulated as the sucrose concentration was increased. Cloning and sequencing revealed multiple cDNA fragments for each signal detected by differential display. RT-PCR analysis of sixteen different cDNAs revealed that eight encoded mRNAs which were upregulated in parallel to the increase in media sucrose. Comparison of the eight upregulated cDNAs to other sequences in GenBank revealed the following: (1) BSS8A had a 100% identity with the last 25 amino acids of an acyl carrier protein from Arabidopsis thaliana, (2) BSS1A displayed homology to a number of sequences of unknown function, (3) BSS1 IB displayed weak but significant homology to a number of sequences of unknown function, (4) BSS13A displayed homology to four members of the thioredoxin family from ,4. thaliana and (5) four Had no significant homology to previously reported sequences which makes them potential candidates to encode lipogenic enzymes. These results indicate that differential display of mRNA may be a simple and rapid method for the identification of sucrose-modulated gene expression changes in this system and for the characterization of novel sequences potentially encoding lipogenic proteins.
xxi, 256 leaves : ill. ; 28 cm.

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24

Stollar, Rachel. "Fine mapping of the nuclear restorer locus for cytoplasmic male sterility in Brassica napus." Thesis, McGill University, 2001. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=34014.

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This thesis will discuss the 'Polima' cytoplasmic male sterility (CMS) system (pol) in Brassica napus (Canola) and detailed genetic mapping of the region surrounding restorer gene ( Rfp) for that system This fine mapping of the Rfp region will facilitate efforts to clone the gene that will eventually lead to its characterization. Knowledge of the structure of Rfp will provide insight in the molecular mechanisms governing mitochondrial gene statement as well as pollen production and may lead to the development of alternative methods of pollination control. In addition, it is possible that nuclear restorer genes for other CMS systems in other crops may be similar to that of the 'Polima' system.
Map based cloning requires the identification of DNA markers tightly linked to Rfp. Two PCR based markers which are located on either side of Rfp were developed. These markers allowed facile screening of a large population.
RFLP markers used in this study are based on the synteny between B. napus and the well known crucifer A. thaliana. (Abstract shortened by UMI.)

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25

Singh, Mahipal. "Molecular analysis of polima cytoplasmic male sterility in Brassica napus." Thesis, McGill University, 1992. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=39754.

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To identify region(s) of the mitochondrial genome that might be involved in specifying the "Polima" (pol) cytoplasmic male sterility (CMS) of Brassica napus, transcripts corresponding to 14 mitochondrial genes and DNA clones representing $>$90% of the mitochondrial genome of Brassica campestris were analyzed in nap (male fertile), pol (male sterile) and nuclear fertility-restored pol cytoplasm plants. CMS-correlated transcriptional differences among these plants were detected only with the ATPase subunit 6 (atp6) gene. Sequence analysis of the atp6 gene regions of pol and nap mitochondrial DNAs show that rearrangements in the pol mitochondrial genome upstream of atp6 have generated a chimeric 224-codon open reading frame, designated orfJ224, that is cotranscribed with atp6. In male sterile plants, most transcripts of this region are dicistronic, comprising both orf224 and atp6 sequences. In fertility restored-plants, genes at either of two distinct nuclear restorer loci specifically alter this transcript pattern, resulting in predominantly monocistronic atp6 transcripts. The effect of the restorer locus on orf224/atp6 transcripts does not seem to be tissue or developmental stage specific. orf224 comprises a portion of the mitochondrial gene, orfB, fused to sequence of unknown origin. The pol mitochondrial genome contains an apparently functional copy of orfB. The expression of the atp6 region is developmentally regulated in pol plants such that levels of monocistronic atp6 transcripts are increased in seedlings as compared to the floral tissue. Preliminary data indicate that the chimeric gene, orf224, is expressed at the protein level in pol plants.

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26

Elina, Helen. "Expression of a Brassica napus mitochondrial gene region associated with cytoplasmic male sterility : transcript initiation, editing, splicing and nuclease processing." Thesis, McGill University, 2007. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=115915.

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Cytoplasmic male sterility (CMS) is a maternally inherited trait of higher plants that can be suppressed by nuclear restorers of fertility ( Rf) genes that normally down-regulate the expression of a CMS-associated mitochondrial gene. In Brassica napus, nap CMS is associated with the expression of the orf222/nad5c/orf2101 mitochondrial gene region and is suppressed by the restorer gene Rfn. I present here an extensive analysis of the expression of the orf222/nad5c/orf2101 region in nap CMS and fertility-restored plants. Using RT-PCR methodology, I mapped transcript initiation sites, processing sites, and 3' termini. I identified two processing events, one within and one immediately downstream of orf222, that are specific to fertility restored plants and I suggest possible mechanisms by which the Rfn protein may recognize cognate RNA substrates. Unexpectedly, I also found that levels of atp8 transcripts are much lower in CMS than in restored plants.
nad5c, one of the components of the nap CMS-associated region, is the small central exon of the nad5 gene. In higher plants, nad5c transcripts must be joined to exons b and d through two group II intron trans-splicing events. I found that in the dicot Brassica and the monocot wheat, proper splicing requires exon c and d joining occur prior to the splicing of c with b. Joining of c to a/b transcripts prior to c/d splicing results exclusively in mis-spliced products in which the 5' end of c is joined to cryptic sites within exon b. It is suggested that intron sequences downstream of c base-pair with exon a, leading to mis-folding of the b/c intron and mis-splicing. In Oenothera, where the c/d intron is further fragmented into a tri-partite intron, mis-splicing does not occur. I suggest that avoidance of mis-splicing may be a factor that drives fragmentation of trans -splicing group II introns and may have contributed to the eventual evolution of spliceosomal RNAs from a group II intron precursor.

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27

Inyang, Enenwan N. "Effect of the host plant on the susceptibility of crucifer pests to the insect pathogenic fungus, Metarhizium anisopliae." Thesis, Imperial College London, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.245611.

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28

L'Homme, Yvan. "Molecular characterization of cytoplasmic male sterility in Brassica napus." Thesis, McGill University, 1994. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=28810.

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In order to identify organizational differences between sterile Polima (pol) and fertile Campestris (cam) mitochondrial genomes that could be linked to cytoplasmic male sterility (CMS), the physical map of the pol mitochondrial genome was constructed and compared to the physical map of the cam mitochondrial genome. The only structural differences between the two genomes are confined to a region encompassed by a 4.5 kb segment, present in pol mtDNA but absent in cam mtDNA. This 4.5 kb CMS-associated pol segment contains a chimeric gene called orf224 that is cotranscribed with atpG and comprises the single mtDNA region expressed differently in fertile, sterile and fertility restored plants which makes it a good candidate for specifying the sterility trait. Sequence analysis of the pol 4.5 kb segment has shown that orf224 was the only significant open reading frame (ORF) within the segment that gives rise to abundant transcripts, strengthening the view that the orf224/atp6 gene region is conferring pol male sterility. The pol 4.5 kb segment is also present and similarly organized in the common Brassica napus nap mtDNA but the sequences flanking the two segments are unrelated. Thus, the 4.5 kb segment appears to have transposed during the evolution of the pol and nap mitochondrial genomes and appears to have been lost in the cam mitochondrial genome. Sequence analysis of the nap segment revealed the presence of an ORF related to but divergent from orf224. This open reading frame (orf222) potentially encodes a protein of 222 amino-acids with 79% homology to the predicted product of orf224. orf222 is co-transcribed with the third exon of the trans-spliced gene, nad5, and another ORF of unknown function. Expression of the orf222 gene region is tightly associated with nap CMS since the levels of orf222 transcripts are significantly reduced upon restoration while the expression of 22 other mitochondrial genes do not consistently correlate with nap CMS. Antibodies were rai

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Foroud, Nora Afsaneh, and University of Lethbridge Faculty of Arts and Science. "Probing the membrane topology of a diacylglycerol acytransferase type I from Brassica Napus." Thesis, Lethbridge, Alta. : University of Lethbridge, Faculty of Arts and Science, 2005, 2005. http://hdl.handle.net/10133/256.

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Diacylglycerol acyltransferase (DGAT), an integral membrane protein of the endoplasmic reticulum, catalyses the final step in the sn-glycerol-3-phosphate pathway leading to triacylglycerol. Although DGAT has been cloned from a variety of species, including the major oilseed crop of Canada, canola (Brassica napus), little is known about the structure/function of the enzyme. BnDGAT1 is the major isoform of type I DGAT (DGAT-I) in microspore-derived cell suspension cultures of B. napus L. cv Jet Neuf, with the possible existence of a truncated form of BnDGAT1 known as BnDGAT2. In order to gain some insight into the topology of the enzyme, type I DGAT from B. napus was investigated using two approaches: (1) in vitro translation in the presence of microsomes and (2) immunochemical analyses of microsomes isolated from cell suspension cultures, both in combination with proteolytic mapping. Difficulties were encountered with the in vitro translation approach, possibly due to proper incorporation of the polypeptide into microsomal vesicles. Two cytocolic regions were identified in BnDGAT1, and one cytosolic region in putative BnDGAT2, using the immunochemical approach, thus providing some insight into the topology of B. napus DGAT-I. The results here support and nine and eight membrane-spanning topology for BnDGAT1 and BnGAT2, respectively.
xvii, 194 leaves ; 29 cm.

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Hutchins, John David. "Antagonism of the stem rot pathogen (Sclerotina sclerotiorum) by microorganisms from oilseed rape flowers : prospects for biological control." Thesis, Imperial College London, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.281747.

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Butterworth, Lisa A. "Interactions of the pathogen leptosphaeria maculans (Desm.) Ces and de Not. and Brassica napus." Thesis, University of East Anglia, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.267462.

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Collison, J. "Influence of plant population and spatial arrangement on yield of winter oilseed rape (Brassica napus L.)." Thesis, University of Newcastle Upon Tyne, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.370876.

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33

Mosiane, M. S. "Diamondback Moth, Plutella xylostella (L.), (Lepidoptera: Plutellidae ), and Other Insects of Canola, Brassica napus L., in Gauteng Province, South Africa." Thesis, Rhodes University, 2002. http://hdl.handle.net/10962/d1018250.

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Canola, Brassics napus L. is a relatively new crop in South Africa. Insect pests have not yet been a major problem, but the notorious brassica specialist, diamondback moth (DBM), Plutella xylostella (L.) (Plutellidae) is establishing itself as a serious pest of this crop. DBM is the most important insect pest of plants from the family Brassicaceae throughout the world. It has developed resistance to all chemical pesticides used against it in the field and to toxins of the bacterium Bacillus thuringiensis. The pest status of DBM in South Africa is lower than in other countries with similar climates. However, due to indiscriminate use of pesticides, local populations of DBM are showing signs of resistance. An initial survey has indicated that in addition to DBM, canola is also attacked by aphids, Myzus persicae (Sulzer), Brevicoryne brassicae (L.), Lipaphis e1ysimi (Kaltenbach), (Aphiade), thrips, Thrips tabaci (Lindeman) and other pests mostly brassica specialists. The study was initiated to determine the composition of the community of insects found on canola, the seasonal phenology of DBM populations in canola, and the composition, relative abundance and seasonality of its parasitoids. Monitoring of the insects was carried out at weekly intervals for three years at Rietondale and Bapsfontein in Gauteng province of South Africa. Berlese funnels have been found to be useful in extracting insects from plants, and were used to indicate the presence ofDBM larvae and other insects found on canola. Adults of DBM were monitored with synthetic pheromone traps; larval and pupal populations were monitored by scouting canola plants. Samples of larvae, pupae and parasitoid cocoons were brought into the laboratory. Parasitoids that emerged were identified and their incidence recorded. Monolepta cf bifasciata (Chrysomelidae) and Listroderes costrirostris (Schoener) (Curculionidae) were the most abundant of the coleopteran pests. (DBM) and Heliothis armigera (H.) (Noctuidae) were most abundant lepidopteran pests of Canola. There was a high proportion of first and second instar larvae as indicated by the results of the Berlese funnels as compared to visual scouting in Bapsfontein. From May to August the infestation level of DBM was high, reaching the maximum of 0.25 larvae per plant in June 1996, then declined and remained low for the rest of the season in Rietondale. From September to December for all three years of the study, the population levels Of DBM were high, reaching a maximum of 9.6larvae per plant in September 1997, and remained low from January to August in Bapsfontein. The number of adult moths per trap per week ranged from 0 to 91 in Rietondale, peaking in January 1996 and September 1997. There was no correlation between infestation levels and the pheromone trap catches. In contrast to Rietondale, there was a high correlation between pheromone trap catches and subsequent larval infestations at Bapsfontein. Although DBM infestation levels were generally low, parasitism levels often reached 100% caused by a complex of parasitoids. During the period of study, the following hymenopteran parasitoids were recorded: Cotesia plutellae (Kurdjumov) and Apanteles eriophyes (Nixon), Braconidae), both larval parasitoids, Diadegma mollipla (Holmgren) (Ichneumonidae), and Oomyzus sokolowskii (Kurdjumov) (Eulophidae), larval-pupal parasitoids, Diadromus collaris (Gravenhorst) (Ichneumonidae) pupal parasitoid, and the hyperparasitoids Mesochorus sp. (Ichneumonidae) and Pteromalus sp. (Pteromalidae). Cotesia plutellae was the most abundant parasitoid occurring throughout the year..

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Lehrman, Anna. "Oilseed rape transformed with a pea lectin gene : target and non-target insects, plant competition, and farmer attitudes /." Uppsala : Dept. of Ecology, Swedish University of Agricultural Sciences, 2007. http://epsilon.slu.se/200795.pdf.

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Hervé, Maxime. "Écologie chimique de l'interaction colza - méligèthe : vers de nouvelles stratégies de contrôle des insectes ravageurs ?" Thesis, Rennes 1, 2014. http://www.theses.fr/2014REN1S070/document.

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Les plantes possèdent de multiples systèmes de défense contre les insectes phytophages. Dans un contexte agronomique, manipuler ces défenses au moyen de la sélection pourrait contribuer à réduire les dommages causés par les insectes ravageurs en augmentant la résistance naturelle des plantes. Cette stratégie se heurte cependant à des contraintes très fortes lorsqu'il s'agit de l'appliquer aux insectes. Après avoir détaillé ces contraintes, nous proposons une démarche alternative aux méthodes classiques. Celle-ci vise à identifier des traits-clés de la plante qui modulent son interaction avec le ravageur. Si de tels traits sont identifiés et validés expérimentalement, ils permettront ensuite de conduire la sélection sans nécessiter d'insecte. Nous avons testé cette démarche dans un système composé du colza (Brassica napus) et du méligèthe Meligethes aeneus, un ravageur majeur de cette culture. Le méligèthe est un coléoptère pollinivore dont les adultes sont généralistes mais ne pondent que sur certaines brassicacées. Les dégâts agronomiques sont causés par ces adultes qui, avant que la floraison ne démarre, détruisent les boutons floraux pour atteindre le pollen qu'ils contiennent. Quatre étapes cruciales de l'interaction ont été étudiées : l'attraction à distance, l'alimentation des adultes, la production et la ponte des œufs, et le développement larvaire. Six génotypes de colza ont été comparés dans une série d'expérimentations au laboratoire. La mise en relation des résultats de préférence/performance de l'insecte avec des profilages métaboliques larges de tissus floraux a permis d'identifier des traits-clés candidats. Les conclusions principales de ce travail sont (i) que la composition biochimique du périanthe est déterminante dans la stimulation de l'alimentation des adultes, et que cette stimulation pourrait être largement sous l'influence d'un petit nombre de composés dont le saccharose ; (ii) que cette stimulation détermine de façon majeure, par un effet domino, la production d'œufs en contraignant l'ovogenèse ; (iii) que la qualité nutritionnelle du pollen impacte à la fois les larves et les adultes, et que cette qualité pourrait être déterminée en bonne partie par la concentration en amidon et en certains glucosinolates (des métabolites secondaires typiques de quelques familles végétales dont les brassicacées). La combinaison des différents résultats obtenus permet également de proposer des hypothèses plus générales, parmi lesquelles le fait que le contexte agronomique dans lequel l'interaction a lieu ait largement influencé, voire perturbé, l'interaction qui liait le méligèthe et les brassicacées sauvages avant que les cultures de colza ne se généralisent. Cette thèse a montré qu'une nouvelle voie était peut-être envisageable pour contribuer à protéger les cultures de façon durable contre les insectes ravageurs, en particulier pour les systèmes agronomiques où les dégâts sont causés à un stade temporairement sensible de la culture
Plants display multiple defense systems against phytophagous insects. Manipulating these defenses by means of selection could contribute to decrease damages caused by insect pests, by increasing natural resistance of crops. This strategy faces great constraints when applied to insects. We first detail these constraints and then propose an alternative approach to classical methods. It consists in identifying key plant traits that determine the intensity of the interaction between the plant and the pest. If such traits are identified, selection could be conducted on the basis if these sole traits, without needing any insect. We tested this approach in a system composed of oilseed rape (Brassica napus) and the pollen beetle (Meligethes aeneus), a major pest of this culture. This coleopteran generalist pollen feeder lays eggs only on certain brassicaceous plants. Agronomical damage arise before plant flowering and are caused by adults, which destroy flower buds to get the pollen they contain. Four crucial steps of the interaction were studied: attraction, adult feeding, egg production and oviposition, and larval development. Six oilseed rape genotypes were compared in a series of experiments conducted in the laboratory. By linking insect preference/performance to large metabolic profiling of bud tissues, we identified candidate key traits. Main conclusions of this work are (i) that biochemical composition of the perianth, especially a few compounds among which sucrose, is determinant for feeding intensity; (ii) that feeding stimulation has an important impact on egg production by constraining oogenesis; (iii) that pollen nutritional quality, probably mostly determined by starch and some glucosinolates, interacts with both pollen beetle larvae and adults. Combination of several results also allows drawing more general hypotheses about the oilseed rape - pollen beetle interaction. One of these is that the agronomical context in which the interaction takes place may have largely influenced, or even disturbed, the interaction that linked this insect and wild brassicaceous plants before oilseed rape cultivation. This thesis showed that a new way might be possible to protect cultures against insect pests. It could be both efficient and sustainable, especially in systems where agronomical damage is caused at a temporary vulnerable plant stage

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Newbert, Max John. "The genetic diversity of Turnip yellows virus in oilseed rape (Brassica napus) in Europe : pathogenic determinants, new sources of resistance and host range." Thesis, University of Warwick, 2016. http://wrap.warwick.ac.uk/79104/.

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The aphid transmitted Polerovirus Turnip yellows virus (TuYV) was found to be widespread with high incidences in oilseed rape (OSR) across Europe. UK, France, Germany and Poland all having >90% TuYV incidence in some OSR crops. From the 179 whole TuYV genomes sequenced in this study the phylogenetic analyses indicated three distinct genetic groups in the UK, two of which were also detected in Europe. These three genotypes were also distinct from the original sequenced TuYV-FL. These groups are proposed to be distinct species due to their genetic distance based on the most variable gene ORF5 and phylogenetic analyses of ORF1, ORF3, ORF4 and ORF5. Mixed TuYV infection was uncommon and only two plant samples had genetically distinct isolates. Whole genome analysis also provided valuable information on two recombination hotspots located within TuYV genes ORF3 and ORF5. Investigation into the epidemiology of TuYV revealed many weed and crop species as hosts, including sugar beet, which it was previously thought not to infect. TuYV isolates detected infecting weed plants in the UK were successfully transmitted to OSR. Previously undescribed hosts, verbascum, geranium, teasel, spear thistle, dock and previously described hosts in the Brassicaceae, Compositae and Lepidium families were found in the UK. A full-length infectious clone of a UK isolate of TuYV has been produced, this will allow further assessment of TuYV in the future. The infectious clone was able to cause systemic infection of TuYV and was aphid transmissible. The Arabidopsis thaliana gene knock-out study did not reveal a single eIF gene or gene linked to virus movement or silencing that could provide extreme broad-spectrum resistance. The gene eIF(iso)4G.1 was able to give a broad-spectrum quantitative resistance, and the potential of eIF3D.2 as well as sucrose symporters SUC1 and SUC2 as candidates for extreme TuYV resistance were discovered. This understanding of the epidemiology and diversity of TuYV is being used to develop strategies for control.

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Seimandi, Corda Gaëtan. "Recherche de nouveaux leviers pour cribler la résistance du colza (Brassica napus) au méligèthe (Brassicogethes aeneus) : de la métabolomique au champ." Thesis, Rennes 1, 2018. http://www.theses.fr/2018REN1B012/document.

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Les insectes phytophages causent des dommages importants aux cultures. Ces insectes sont principalement contrôlés par l’utilisation d’insecticides mais les effets néfastes des composés utilisés sur la santé humaine et l’environnement ainsi que l’apparition de populations résistantes à ces composés imposent de trouver des stratégies de lutte alternatives. Sélectionner des plantes pour leur résistance aux insectes pourrait être une solution intéressante. Un frein majeur au développement de cette stratégie est le fait qu’un grand nombre de génotypes doit être criblé pour identifier des sources de résistance et que le phénotypage est souvent complexe et limite les possibilités de criblage à grande échelle. Pour lever ces verrous, il est important de comprendre les mécanismes à l’origine des résistances. Une fois ces mécanismes précisés dans le cadre de l’interaction entre une culture et un ravageur, l’identification de traits clés de cette interaction permet d’envisager l’utilisation de biomarqueurs de la résistance qui peuvent fortement simplifier le phénotypage. Ce type d’approche a été conduit au cours de cette thèse dans le cadre de l’interaction entre le colza (Brassica napus) et l’un de ses principaux ravageurs, le méligèthe (Brassicogethes aeneus). Des travaux antérieurs avaient mis en évidence l’existence de certains composés biochimiques présents dans le périanthe des boutons floraux et corrélés au niveau d’attaque de différents génotypes de colza. Ces résultats avaient été obtenus au laboratoire et il était nécessaire de les confirmer dans des conditions de culture réalistes. Le premier objectif de cette thèse était donc de développer une méthode permettant de cribler au champ différents génotypes de colza pour leur résistance au méligèthe afin de valider ou non le potentiel des composés biochimiques identifiés précédemment comme biomarqueurs mais aussi d’en identifier de nouveaux. Le second objectif de ce travail était de mieux comprendre l’écologie alimentaire du méligèthe afin d’identifier de nouvelles cibles potentielles pour la sélection de plantes résistantes. Nous avons mené plusieurs expérimentations sur le terrain qui nous ont permis de développer une méthode de crible au champ des génotypes de colza pour leur résistance au méligèthe. Cette méthode a mis en évidence l’existence de différences de résistance fortes et robustes entre génotypes parmi une gamme de 19 génotypes testés. Les biomarqueurs potentiels précédemment identifiés n’ont pas été validés au champ mais deux autres composés semblent influencer la résistance au méligèthe et pourraient être utilisés comme futurs biomarqueurs. Ces expériences au champ ont aussi permis de montrer que la biochimie des périanthes était très dépendante des conditions environnementales, ce qui pourra compliquer le travail de sélection. Par ailleurs, des expériences de développement réalisées en conditions contrôlées ont montré que le méligèthe utilisait le nectar présent dans les fleurs de colza mais que celui-ci ne semblait pas affecter son développement. Le pollen semble, jouer un rôle important sur son développement mais les larves parviennent à se développer sans son apport. Les expériences sur le comportement alimentaire du méligèthe adulte ont montré que cet insecte avait un patron d’attaque spécifique sur les inflorescences de colza en s’alimentant avant tout sur les boutons de petite taille (donc moins riches en pollen par rapport aux gros). Il semble que la disponibilité mais surtout l’accessibilité du pollen médiée par le périanthe joue un rôle essentiel dans le comportement de cet insecte. Ce travail a permis de mieux comprendre le comportement alimentaire du méligèthe et d’identifier des traits importants pour son développement. Ce travail montre que des résistances modérées existent au sein du colza et qu’elles pourraient être utilisées pour la sélection variétale. Il pointe aussi les limites des approches basées sur des biomarqueurs biochimiques
Herbivorous insects cause important yield losses to crops. These insects are mainly managed through insecticides but negative effects of used compounds on the human health and the environment as well as the development of resistant pest populations impose finding alternative strategies to manage them. Breeding plants for enhanced resistance to insects is an attractive strategy. This kind of strategy was already implemented to manage insects but examples of its utilisation remain rare. The main limitation of this strategy is that a large number of genotypes needs to be screened through generally complex phenotyping methods to identify resistances. To circumvent these issues, an approach based on the understanding of plant defence mechanisms and the utilisation of biochemical biomarkers linked to resistance could be interesting. During this PhD, this kind of approach was developed on the oilseed rape (Brassica napus) and one of its main pests, the pollen beetle (Brassicogethes aeneus). Previous studies identified chemical compounds present in the perianth of flower buds and correlated to oilseed rape resistance to pollen beetle. However these studies were carried out in the laboratory and need to be validated in field conditions. Moreover, information on pollen beetle feeding ecology are still lacking while they could help identifying new targets for breeding. The first objective of this PhD is to develop a method allowing to screen resistance to the pollen beetle in the field. This method will allow to confirm the potential biomarkers previously identified and to look for additional biomarkers. The second objective of the present work was to better understand key steps in the interaction between the pest and its host plant to identify potential new target traits for resistance. For this purpose, the importance of food sources present in flowers such as pollen and nectar on pollen beetle development and the factors impacting the feeding pattern of adults on the inflorescence were investigated. We conducted field experiments in two different sites and for two consecutive years and propose a method allowing to screen oilseed rape resistance to pollen beetle in the field. Using this method, we were able to identify genotypes with moderate levels of resistance among a set of 19 genotypes. Previously identified biochemical biomarkers were not correlated with plant resistance in the field but new markers were identified (i.e. quinic acid and arginine). Our field experiments also showed that plant composition is highly variable according to the environment and this variability could affect usefulness of these markers during plant breeding programs. Experiments under controlled conditions also showed that pollen beetle used nectar for feeding but that it did not seem to affect its development. Pollen, on the other hand, seemed to have a more important impact but was not indispensable to pollen beetle development. The study of the pollen beetle feeding behaviour showed that this insect has a surprising feeding pattern on oilseed rape inflorescences and that small buds are more used for feeding than large buds that contain more pollen. It seems that accessibility and to a lesser extend availability of feeding resource explain this pattern and that the perianth has a major role on this preference. These experiments allowed to better understand the pollen beetle feeding ecology and to identify plant traits important for its development. Our work showed that moderate levels of resistance are present in oilseed rape and could be used in breeding programs. Limitations of approaches based on biochemical biomarkers are discussed

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Wargachuk, Richard Burns. "Fine mapping and functional analysis of the radish Rfo nuclear restorer locus." Thesis, McGill University, 2004. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=81454.

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Cytoplasmic male sterility (CMS) is a widespread, maternally inherited trait that results in an inability of plants to produce functional pollen. The Ogura CMS system originated in radish, but has since been transferred to, and confers male sterility on, plants in the related genus Brassica . A gene which restores male fertility is needed for the Ogura CMS system to be exploited commercially for hybrid seed production in oilseed species such as Brassica napus. The restorer gene Rfo is a dominant radish nuclear gene that restores the male fertility to plants with Ogura cytoplasm. This gene has been transferred into Brassica napus through intergeneric crosses; however the introgressed segment of radish DNA contains an unknown number of genes, some of which confer undesirable traits, such as an elevated content of seed glucosinolates, antinutritive compounds that render the seed meal unusable as animal feed. A fine scale linkage map of the region in radish containing Rfo was constructed, and a map-based cloning approach relying on synteny between radish and Arabidopsis was used to clone Rfo. A radish gene encoding a 687 amino acid protein with a predicted mitochondrial targeting presequence was found to confer male fertility upon transformation into Ogura CMS B. napus . This gene, codes for a pentatricopeptide repeat (PPR)-containing protein with multiple, in this case 16, PPR domains. Two similar genes that do not appear to function as Rfo flank this gene. A transcript representing a non-functional allele (rfo) was detected in sterile radish plants. Comparison of the Rfo region with the syntenic Arabidopsis region indicates that a PPR gene is not present at the Rfo-equivalent site in Arabidopsis , although a smaller and related PPR gene is found about 40 kb from this site.

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Geddy, Rachel Gwyneth. "Location and expression of genes related to the cytoplasmic male sterility system of Brassica napus." Thesis, McGill University, 2006. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=100608.

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Cytoplasrnic male sterility (CMS) is a maternally inherited defect in the production of pollen, the male gamete of the flower. This sterility can be suppressed by nuclear Restorer of Fertility (Rf) genes that normally downregulate the expression of the CMS-associated novel mitochondrial gene. In Brassica napus, nap CMS and pol CMS are associated with related chimeric mitochondrial genes orf222 and orf224, respectively. CMS in both nap and pol is associated with a polar loss of locule development, loss of synchronous locule development and clumping of sporogenous tissue away from the tapetal cell layer, as well as secondary effects on petal and bud formation. In nap CMS, early accumulation of orf222 transcripts in the locule regions of developing anthers is associated with sterility, while the absence of orf222 transcripts from the locules is associated with fertility restoration. Accumulation of novel antisense transcripts of atp6 in a cell specific manner which matches that of sense transcripts of orf222 and atp6 in nap CMS anthers may be indicative of a post-transcriptional regulatory mechanism associated with CMS in flower buds.
Restoration of fertility in Brassica napus nap and pol CMS is associated with nuclearly encoded genes Rfn and Rfp, respectively. These restorers are very closely linked to one another, and may be allelic. Further efforts to isolate Rfp have narrowed the genomic region to approximately 105 kb of a syntenic region in Arabidopsis thaliana. Cosmid clones isolated from a library of Brassica rapa genomic DNA introgressed with Rfp have been successfully sorted into contigs through the application of the amplified fragment length polymorphism technique. The region to which Rfp is mapped is syntenic to a region of Arabidopsis DNA that is a duplication of a second location at the 23 megabase region of chromosome 1 of that genome. This region contains pentatricopeptide (PPR) motif-encoding genes that are highly related to other restorers of fertility of other species. By inference, Rfp from Brassica napus may encode PPR motifs. The PPR genes related to these previously characterized restorers of fertility are often found alongside the restorer genes existing as mini-clusters of several PPR-encoding genes. This is likely caused by selective pressure acting on PPR-encoding genes that resulted in diversification and multiplication of these genes. In addition, the PPR genes of this duplicated region are not syntenically located, whereas the non-PPR-encoding genes maintain their syntenic locations. The same is true for orthologous comparisons between Arabidopsis and other plant species. PPR genes are therefore malleable and capable of alteration in response to changing environmental pressures, such as the evolution of sterility inducing genes.

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Vazquez-Carrasquer, Victor. "Identification and genotypic variability of plant traits early determining nitrogen use efficiency (NUE) in winter oilseed rape under low-N inputs." Thesis, université Paris-Saclay, 2021. http://www.theses.fr/2021UPASB002.

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Améliorer le rendement du colza dans un contexte de bas intrants azotés (N) est un enjeu majeur de sélection. Ceci impose une connaissance approfondie de la variabilité génétique des processus sous-tendant l’efficacité d’utilisation de l’azote (NUE, rendement en graines par unité d’azote disponible). Cette thèse vise à mieux comprendre les processus écophysiologiques contribuant à la NUE et à ses composantes sous faible nutrition azotée, en identifiant et hiérarchisant les principaux traits sous-tendant leur variabilité génotypique. Six génotypes de colza d’hiver ont été étudiés en conditions semi-contrôlées sous des doses d’azote contrastées. Nous avons montré que la variable NUE_DM (biomasse totale produite par unité d’azote disponible) est un indicateur précoce de la NUE à la récolte valable dès la montaison, qui nous a permis de caractériser dynamiquement la NUE. L’efficience d'absorption d’azote (NUpE, N absorbé par unité d’azote disponible) s’est révélée être une composante majeure de la NUE sous contrainte azotée, expliquant 80 % des variations avant la floraison, et plus de 30 % après. De plus, sa variabilité génotypique dépend de la biomasse des racines fines et non de l’absorption spécifique d'azote. Grâce au développement d’un cadre conceptuel de modélisation du fonctionnement du colza décrivant les flux de carbone et d’azote dans la plante entière et valable jusqu’à floraison, nous avons fait ressortir l'assimilation spécifique de carbone, la part de carbone allouée aux tiges et la proportion de racines fines comme paramètres clés de la réponse génotypique à l’azote. Nos résultats suggèrent que la NUpE et la proportion de racines fines seraient des indicateurs de la NUE permettant de cribler précocement des variétés à haut débit
Improving rapeseed yields in a low-Nitrogen (N) agricultural context is a major issue for breeding. It requires a thorough knowledge of the genotypic variation of the processes related to Nitrogen Use Efficiency (NUE, seed yield per unit of N available). This PhD aims at better understanding the ecophysiological processes determining the NUE and its components under low-N availability by identifying and hierarchizing the main traits supporting observed genotypic variation. Six winter oilseed rape genotypes were investigated throughout the crop cycle under semi-controlled conditions and contrasting N-conditions. We proposed NUE_DM (plant dry matter per unit of N available), as a new proxy of NUE at harvest, valid as early as the beginning of stem elongation. This proxy allowed us to dynamically characterize NUE, highlighting NUpE (plant N-amount per unit of N available) as a main contributor of NUE under low-N conditions, which explained up to 80% of the NUE_DM variations before flowering, and more than 30% after. Moreover, NUpE genotypic variability resulted from fine root growth rather than specific N-uptake differences. We developed a whole-plant conceptual modeling framework of carbon and nitrogen absorption and partitioning for winter oilseed rape. This framework, validated up to flowering, highlighted specific carbon assimilation, carbon partitioning between leaves and stems, and fine root ratio as critical traits explaining contrasting genotypic behavior to N-conditions. Our results suggest NUpE and fine root ratio as promising traits for screening larger sets of varieties for NUE breeding purposes

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Piacentini, Patricia de Oliveira. "Extratos de brássicas no controle de Oídio em pepineiro." Universidade Tecnológica Federal do Paraná, 2017. http://repositorio.utfpr.edu.br/jspui/handle/1/2365.

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CAPES
Os objetivos deste estudo foram avaliar o efeito dos extratos de canola (Brassica napus L.) e mostarda-da-índia (Brassica juncea), in vitro, sobre a severidade de Oídio (Oidium sp.) em discos cotiledonares de pepineiro e a germinação de conídios do fungo e comparar esses extratos com controle químico (enxofre inorgânico e tiofanato metílico + clorotalonil), leite cru de vaca a 10 % e óleo de neem, também in vitro, e no controle do Oídio em pepineiro, em casa de vegetação. Para isso, foram realizados três experimentos, in vitro. No primeiro, testaram-se três métodos de preparo (aquoso, macerado e infusão) dos extratos de canola e mostarda-da-índia na dose de 12% sobre a severidade do Oídio em discos cotiledonares de pepineiro e a germinação de conídios do fungo. Nesse experimento, todos os modos de preparo dos extratos de canola e mostarda-da-índia reduziram mais de 35% a severidade da doença nos discos cotiledonares e a germinação dos conídios do fungo. No segundo experimento, testaram-se as doses de 3 a 12% dos extratos das brássicas, preparados por maceração, sobre as mesmas variáveis do ensaio anterior. A dose de 12% dos extratos das brássicas reduziu a severidade da doença nos discos cotiledonares de pepineiro em mais de 59% e a germinação dos conídios do fungo em mais de 52%. No terceiro experimento, testaram-se os extratos macerados a 12% dessas brássicas, o leite cru de vaca a 10%, o óleo de neem e os fungicidas, também sobre as mesmas variáveis. Nesse ensaio, os tratamentos contento os extratos de brássicas reduziram mais de 80% a severidade do Oídio nos discos cotiledonares de pepineiro, em relação ao tratamento testemunha. Porém, no teste de germinação de conídios do fungo, apenas os tratamentos contendo os fungicidas foram eficientes, reduzindo em 65% a germinação dos conídios do fungo. Posteriormente foram realizados experimentos, em casa de vegetação, para comparar a eficiência desses tratamentos no controle do Oídio em pepineiro, em dois anos de cultivo. Os extratos das brássicas reduziram a severidade e a taxa de progresso da doença nos dois anos de cultivo. O extrato de mostarda-da-índia, em relação aos tratamentos testemunha seca e com água, reduziu a área abaixo da curva de progresso da doença (AACPD) da severidade de Oídio, em média, 68,7 e 57% e o extrato de canola reduziu, em média, 67,1 e 59,4%, nos anos 1 e 2, respectivamente. Quando os extratos de canola e mostarda-da-índia foram comparados aos tratamentos testemunha seca e com água, constatou-se que a redução da severidade final da doença foi superior a 70 e 65%, nos anos 1 e 2, respectivamente. Os extratos de canola e mostarda-da-índia apresentaram maior controle da doença, comparado ao obtido no tratamento contendo leite cru de vaca a 10%, e próximo ao controle do tratamento com óleo de neem. Os fungicidas apresentaram os melhores controles da severidade e da taxa de progresso da doença, com redução superior a 99% da severidade final da doença e da AACPD da severidade de Oídio. Conclui-se, portanto, que os extratos das canola e mostardada-índia têm potencial de controle de Oídio em pepineiro, em casa de vegetação.
The objectives of this study were to evaluate the effect of canola (Brassica napus L.) and mustard (Brassica juncea) extracts, in vitro, on the severity of powdery mildew (Oidium sp.) in cucumber cotyledon discs and on the germination of fungal conidia, and to compare these extracts with chemical controls (inorganic sulphur and methyl thiophanate + chlorothalonil), 10% cows milk and neem oil, in vitro and also in the control of powdery midew in greenhouse cucumbers. To achieve this, three experiments were carried out in vitro. In the first, three methods of preparation (aqueous, macerated and infusion) of the extracts of canola and mustard were evaluated for the dose of 12% on the severity of powdery mildew in cotyledon discs and the germination of fungal conidia. In this experiment, all modes of preparation of extracts of canola and mustard reduced the severity of the disease in the cotyledon discs and the germination of the fungal conidia by more than 35%. In the second experiment, doses from 3 to 12% of the brassica extracts, prepared by maceration, were tested on the same variables of the previous experiment. The 12% dose of the brassica extracts reduced the severity of the disease in cucumber cotyledon discs by more than 59% and the germination of fungal conidia by more than 52%. In the third experiment, the 12% dose of the macerated extracts of the two brassicas were tested, alongside 10% raw cow's milk, neem oil and fungicides, using the same variables as previously. In this trial, the treatments containing the brassica extracts reduced powdery mildew severity by more than 80% in the cucumber cotyledon discs, in relation to the control treatment. However, in the fungal conidia germination test, only the treatments containing the fungicides were efficient, reducing the germination of the fungal conidia by 65%. After this, experiments were carried out in a greenhouse to compare the efficiency of these treatments in the control of powdery mildew in cucumber, over a two year period of cultivation. The extracts of the brassicas reduced the severity and rate of disease progress over the two year period. The mustard extract, in relation to the dry and water control treatments, reduced the area under the disease progress curve (AUDPC) for powdery mildew severity, it by a mean of 68.7 and 57%, and the canola extract reduced it by a mean of 67.1 and 59.4%, in years 1 and 2, respectively. When the extracts of canola and mustard were compared to the dry and water control treatments, it was found that the reduction of the final severity of the disease was superior to 70 and 65%, in years 1 and 2, respectively. The extracts of canola and mustard showed greater control of the disease, compared with that obtained in the treatment containing raw cow's milk at 10%, and was close to the control of the treatment with neem oil. The fungicides presented the best control of disease severity and disease progression rate, with a reduction of final disease severity and in the AUDPC of the mildew severity by more than 99%. It is concluded, therefore, that the extracts of canola and mustard have the potential to control powdery mildew under greenhouse conditions.

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42

Frearson, David. "The movement and host-selection of three inflorescence insect pests of oilseed rape and their parasitoids in relation to host-plant characteristics and environmental conditions." Thesis, University of Reading, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.433448.

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43

Schaefer-Koesterke, Heike Verfasser], Stefan [Akademischer Betreuer] Vidal, Heiko [Akademischer Betreuer] [Becker, and Bernd [Akademischer Betreuer] Ulber. "Effect of plant traits on host selection and performance of rape stem weevil (Ceutorhynchus napi Gyll.) (Col.: Curculionidae) on resynthesized lines and cultivars of oilseed rape (Brassica napus L.) / Heike Schaefer-Koesterke. Gutachter: Stefan Vidal ; Heiko C. Becker ; Bernd Ulber. Betreuer: Stefan Vidal." Göttingen : Niedersächsische Staats- und Universitätsbibliothek Göttingen, 2015. http://d-nb.info/1072820447/34.

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44

Scobie, Andrew Rutherford. "Understanding the causes of reproductive failure in two rare Scottish plants, Linnaea borealis L. and Spiranthes romanzoffiana Cham. and the implications for future conservation management." Thesis, Available from the University of Aberdeen Library and Historic Collections Digital Resources. Restricted: no access until Dec. 21, 2011, 2009. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?application=DIGITOOL-3&owner=resourcediscovery&custom_att_2=simple_viewer&pid=59437.

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45

Knüfer, Jessica Verfasser], Andreas von [Akademischer Betreuer] Tiedemann, Petr [Akademischer Betreuer] Karlovsky, and Heiko [Akademischer Betreuer] [Becker. "Improvement of Winter Oilseed Rape Resistance to Verticillium longisporum - Assessment of Field Resistance and Characterization of Ultrastructural Plant Responses / Jessica Knüfer. Gutachter: Petr Karlovsky ; Heiko C. Becker. Betreuer: Andreas von Tiedemann." Göttingen : Niedersächsische Staats- und Universitätsbibliothek Göttingen, 2013. http://d-nb.info/1044415002/34.

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46

Fismes-Bemer, Joëlle. "Effet de la fertilisation azotée et soufrée et d'un inhibiteur de nitrification (ATS) sur la nutrition azotée et soufrée du colza." Vandoeuvre-les-Nancy, INPL, 1998. http://www.theses.fr/1998INPL062N.

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Le colza est une plante exigeante en azote pour son développement et la production de graines. C’est en outre une plante particulièrement sensible aux carences en soufre car elle utilise le soufre dans de nombreuses réactions métaboliques mais aussi pour la synthèse d'acides aminés soufrés. Cependant, la fertilisation azotée et soufrée du colza doit être raisonnée afin d'augmenter productivité et qualité tout en limitant les pertes d'éléments fertilisants qui occasionnent surcoût et pollution. Le sol argilo-calcaire de lorraine étudié est riche en azote et en soufre totaux, principalement immobilisés dans les fractions fines. Ce sol est cependant peu favorable à la minéralisation de l'azote et du soufre organiques. Par contre, la nitrification de l'ammonium y est très rapide, d'où des pertes non négligeables d'azote par dénitrification et lessivage des nitrates, et l'intérêt porte aux inhibiteurs de nitrification et d'uréase. L’azote et le soufre apportés sont de plus rapidement immobilisés dans le sol par les micro-organismes. Cependant, cette faible disponibilité des engrais est compensée par un effet stimulant de la fertilisation sur la minéralisation de l'azote et du soufre natifs du sol. L’azote et le soufre étant indissociables dans les mécanismes de synthèse des acides aminés et des protéines, nous avons aussi mis en évidence l'influence réciproque de ces 2 éléments sur leur prélèvement respectif par le colza, leur distribution et leur assimilation dans la plante. Ainsi, un déséquilibre entre l'azote assimilable et le soufre assimilable a des répercussions sur la production des graines et leur qualité. En tant qu'inhibiteur de nitrification et d'uréase, l'ATS s'est révélé peu efficace en sol argilo-calcaire en raison des propriétés physiques, chimiques et biologiques de ce sol. Il agit en effet sur la dynamique de l'azote du sol seulement à des doses élevées et pendant une période courte (4 semaines). Quant à son impact sur le prélèvement d'azote par les plantes, il est dû essentiellement à sa composition soufrée.

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Köslin-Findeklee, Fabian [Verfasser]. "The role of leaf senescence in relation to nitrogen uptake and translocation to the reproductive plant organs for cultivar differences in nitrogen efficiency in winter oilseed-rape (Brassica napus L.) / Fabian Köslin-Findeklee." Hannover : Technische Informationsbibliothek und Universitätsbibliothek Hannover (TIB), 2015. http://d-nb.info/1068923954/34.

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Valdés, Valázquez Ariana Istar [Verfasser], Christian [Akademischer Betreuer] [Gutachter] Möllers, and Petr [Gutachter] Karlovsky. "Inheritance of microspore embryogenic potential and direct embryo to plant conversion in the oilseed rape DH population DH4079 x Express 617 / Ariana Istar Valdés Valázquez ; Gutachter: Christian Möllers, Petr Karlovsky ; Betreuer: Christian Möllers." Göttingen : Niedersächsische Staats- und Universitätsbibliothek Göttingen, 2017. http://d-nb.info/1132336791/34.

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Zheng, Xiaorong [Verfasser], Tiedemann Andreas [Akademischer Betreuer] Von, Tiedemann Andreas [Gutachter] Von, and Petr [Gutachter] Karlovsky. "Verticillium longisporum on oilseed rape (Brassica napus L.) : Differential roles of salicylic acid, seed transmission and plant colonization in greenhouse and field conditions / Xiaorong Zheng ; Gutachter: Andreas Von Tiedemann, Petr Karlovsky ; Betreuer: Andreas Von Tiedemann." Göttingen : Niedersächsische Staats- und Universitätsbibliothek Göttingen, 2020. http://d-nb.info/1203875487/34.

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Swarts, Nigel. "Integrated conservation of the rare and endangered terrestrial orchid Caladenia huegelii H.G. Reichb /." Connect to this title, 2007. http://theses.library.uwa.edu.au/adt-WU2008.0044.

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Dissertations / Theses on the topic 'Rape (Plant)'

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