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1
Fryer, Shirley Anne. "Genetic transformation of oilseed rape". Thesis, University of Wolverhampton, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.317928.
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2
Wright, Alan. "Analysis of glucosinolates in oilseed rape". Thesis, University of Wolverhampton, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.297014.
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Four methods of analysis for the determination of total and individual glucosinolates in Brassica napus cultivars (ie Gas Chromatography (GC), High Pressure Liquid Chromatography (HPLQ, Glucose Release, and X-ray Fluorescence Spectrometry (XRF)) were developed, refined, validated and applied. These were used to investigate both high and low glucosinolate cultivars of rapeseed (oilseed rape, Brassica napus), and reproducibility (between replicates) and repeatability (between analysis days) of these methods was assessed. From these studies, an indirect method of glucosinolate determination, involving X-Ray Fluorescence analysis, proved to give the least variable results. Furthermore, this was markedly more rapid than the other methods of analysis. Of the methods assessed for the determination of individual glucosinolates, High Pressure Liquid Chromatography (HPLC) gave less variable results than Gas Chromatography (the European Community (EC) recommended method for glucosinolate determination in oilseed rape at the time of study). Thus, BPLC and XRF analysis were selected as methods for subsequent glucosinolate analysis in the remainder of the study. Effects of geographicallo cation in relation to atmospherics ulphur depositiona nd plant sulphur uptake in Brassica napus cv Ariana grown throughout the UK were determinedin two consecutivey ears. An initial study comparedg lucosinolatele vels in rapeseed samples from 211 sites. A second more detailed study involved determinationo f foliar sulphurl evels (by XRF analysis)a t three stagesd uring plant developmenftr om selecteds itest hroughoutt he UK, and comparisono f thesew ith glucosinolate levels in the harvested seed from these sites. The results of these investigations proved comparable between years, with final glucosinolate levels generally corresponding to atmospheric sulphur deposition levels. Furthermore, high glucosinolatele vels in harvesteds eedg enerallyc orrespondewd ith high sulphur levelsi n foliage ast he plantse ntereds eed-podd evelopment.A series of controlled environment and glasshouse experiments were developed to investigate the effects of sulphur nutrition on glucosinolate development in rape plants during growth. These highlighted that glucosinolate levels in plant material could be manipulated with variation in supplied nutrients. Furthermore, plants initially propagated with sulphur-complete nutrient in hydroponic media, then transferred to sulphur-free nutrient mid-development, were found to give good seed yields with substantially lower glucosinolate levels. In conclusion, attention must be given to choosing the appropriate method for analysis of glucosinolates. Secondly, sulphur availability and sulphur status are critical factors in the determination of glucosinolatelevels, and the relationship between these factors merits further study
3
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.
4
Mulyati. "Zinc requirements of transplanted oilseed rape". Murdoch University, 2004. http://wwwlib.murdoch.edu.au/adt/browse/view/adt-MU20060109.135933.
Pełny tekst źródłaStreszczenie:
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.
5
Batra, Neelu. "Optimisation of trierucin content in oilseed rape". [S.l.] : [s.n.], 2005. http://deposit.ddb.de/cgi-bin/dokserv?idn=980116198.
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6
Goatham, Teresa Ann. "Epidemiology of Sclerotinia infection of oilseed rape". Thesis, University of Nottingham, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.290406.
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7
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.
8
Sharpe, Andrew Glenn. "Marker-assisted breeding in oilseed rape (Brassica napus)". Thesis, University of East Anglia, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.361724.
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9
Da, Silva Paulo Maria Ferreira Rodrigues. "Starch metabolism during embryo development of oilseed rape". Thesis, University of East Anglia, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.359277.
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10
Poole, V. A. "Resistance of oilseed rape to light leaf spot". Thesis, University of Nottingham, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.332739.
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11
Hawkins, Edward. "Aphid movement and microclimate in winter". Thesis, University of Nottingham, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.339655.
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12
Murphy, Lee Anne. "Vernalization response in spring oilseed rape, Brassica napus L". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/nq23642.pdf.
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13
Howell, Philip Martin. "Marker-assisted selection and quantitative genetics in oilseed rape". Thesis, University of East Anglia, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.267464.
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14
Jay, Chantelle N. "Studies of beet western yellow virus in oilseed rape". Thesis, University of Nottingham, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.319500.
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15
Hayter, Katrina Elizabeth. "The pollination dynamics of oilseed rape (Brassica napus L.)". Thesis, University of Exeter, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.439826.
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16
Byers, Susan D., i University of Lethbridge Faculty of Arts and Science. "Stimulation of microsomal diacylglycerol acyltransferase activity from microspore-derived cell suspension cultures of oilseed rape". Thesis, Lethbridge, Alta. : University of Lethbridge, Faculty of Arts and Science, 1999, 1999. http://hdl.handle.net/10133/101.
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Several factors including an unidentified endogenous substance were found to stimulate microsomal diacylglycerol acyltransferase (DGAT, EC 2.3.1.20) from a microspore-derived cell suspension culture of oilseed rape (Brassica napus L. cv Jet Neuf). Mg2+ salts were found to stimulate microsomal DGAT 14 to 23-fold. ATP and CoA were also found to stimulate the enzyme 2.4 and 12 fold respectively, although the effects were decreased in the presence of high Mg2+ concentrations. While microsomal DGAT activity was only slightly increased by the concentration of exogenous diacylglycerol in the reaction mixture it was increased substantially by the addition of exogenous phosphatidate. Other phospholipids tested were not found to have this stimulatory effect. During attempts to investigate possible covalent modification of the enzyme, the soluble fraction obtained from cell suspension homogenate was found to contain a small metastable organic molecule(s) which stimulated DGAT activity. Stimulation of microsomal DGAT by this factor was concentration dependent but not dependent on preincubation time.xiii, 95 leaves : ill. ; 28 cm.
17
Cuthbert, Janice Louise. "Transgenic bromoxynil resistant oilseed rape, biological cost and outcrossing studies". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape10/PQDD_0005/MQ45035.pdf.
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18
Bouttier, Claire. "Pod and seed development in oilseed rape (Brassica napus L)". Thesis, University of Cambridge, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.277706.
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19
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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20
Coupe, Simon Allan. "Changes in gene expression during pod development in oilseed rape". Thesis, University of Nottingham, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.385973.
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21
Bilsborrow, P. E. "Physiology of yield production in oilseed rape (Brassica napus L.)". Thesis, University of Nottingham, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.370355.
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22
Scott, Susan Elizabeth. "Predicting transgene movement from GM oilseed rape (Brassica napus L.)". Thesis, University of Reading, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.314253.
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23
Giannitsopoulos, Michail. "Optimising conservation tillage systems for wheat and oilseed rape production". Thesis, Cranfield University, 2017. http://dspace.lib.cranfield.ac.uk/handle/1826/13661.
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The aims of the thesis are to determine the effect of different conservation tillage systems on the agronomic, environmental and economic performance of a wheat and oilseed rape rotation, and to understand the processes involved so that the systems can be improved. The field research examined five systems over three seasons (September 2013 to August 2016) in two fields (one clay and one clay loam) in Northamptonshire. The most disruptive tillage treatment was the Farm system comprising the use of a Sumo Trio when establishing oilseed rape, and the Sumo Trio and a Kuhn seed drill when establishing wheat. The least disruptive system was a Väderstad Seed Hawk or Rapid. The other three treatments were all one pass conservation tillage systems comprising a Claydon Hybrid Drill, a Mzuri Pro til 3, and a Sumo Deep Tillage Seeder (DTS). To understand the effect on draught and soil disturbance, specific components of the systems were tested under controlled conditions at Cranfield University’s soil bin facility. The shallow working Väderstad required the lowest draught and disturbed less soil than deep working treatments. A low aspect ratio (working depth/implement width) and rake angle reduced the draught. In the field immediately after tillage, the Farm system showed the greatest reduction in bulk density and penetration resistance at 0-50 mm and 150-200 mm, but this effect was not maintained during the season. The level of surface residue was lowest (15%) with the Farm system and greatest (75%) with the Väderstad. The shallow Väderstad led to the highest earthworm abundance in all years and both fields, proportions of water stable aggregates and microbial biomass carbon in third and first year respectively. In the clay field, blackgrass infestation doubled from 8.2% in 2013-14 to 16.0% in 2015-16; it was not a major problem in the clay loam field. Due to high variability, there was no significant effect (p>0.05) of tillage treatments on the yield of wheat and oilseed rape over the 3-year trial period in either field, except when delayed drilling of oilseed rape with the Sumo DTS in September 2015 which led to reduced yields. At a reduced significance level of p=0.15, higher yields observed for Väderstad and Mzuri in the clay soil were associated with higher levels of organic matter. The relative profitability of the five systems was primarily determined by the assumed yields and secondly by the cost of the systems. The predicted annual net margin for the five systems varied from £545 to £659 ha ̄1. The calculated cost of the five tillage systems (assuming working areas ranging from 370 to 1,100 ha) ranged from £11 to £31 ha ̄1 a ̄1, with the lowest cost achieved by the 6 m Claydon system. Assuming blackgrass weeds are not an issue, shallow low disturbance systems can result in low costs, improved soil biology and carbon storage, and sustainable high yields.
24
Mylchreest, S. J. "Development of Sclerotinia stem rot on cultivars of oilseed rape". Thesis, Imperial College London, 1985. http://hdl.handle.net/10044/1/37798.
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25
Norris, Carol Eileen. "Components of gene flow in oilseed rape (Brassica napus L.)". Thesis, University of Cambridge, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.620546.
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26
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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27
Nyikako, John Awan. "Genetic variation for nitrogen efficiency in oilseed rape (Brassica napus L.)". [S.l.] : [s.n.], 2003. http://deposit.ddb.de/cgi-bin/dokserv?idn=969936753.
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28
Foster, S. J. "Development of diagnostic techniques for Pyrenopeziza brassicae on winter oilseed rape". Thesis, University of Cambridge, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.599134.
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Using sequence information from the mating type idiomorphs (MAT-1 and MAT-2) of P. brassicae, the causal agent of light leaf spot of winter oilseed rape (Brassica napus ssp. oleifera), two PCR-based diagnostic assays were developed. The first assay was designed as a general diagnostic tool for P. brassicae and was shown to be specific, amplifying a 750 base pair (bp) product from genomic DNA from over 50 isolates of P. brassicae and not from DNA from a number of other fungal species pathogenic on oilseed rape or from the closely related discomycete Tapesia yallundae. The second assay was designed to differentiate between the two mating types (MAT-1 and MAT-2) of P. brassicae, and was also specific to P. brassicae. Both assays were ale to detect the presence of P. brassicae from DNA extracted from oilseed rape leaves with light leaf spot symptoms. The sensitivities of both of the assays were increased by using templates consisting of mixtures of NDA from P. brassicae and B. napus compared with DNA from P. brassicae alone. Using a nested PCR approach, the sensitivity of the general diagnostic assay was increased by two orders of magnitude and it was able to detect the presence of P. brassicae prior to the development of visible symptoms on oilseed rape leaves. As a first step towards the development of an immuno-diagnostic tool for light leaf spot, the feasibility of adopting a targeted approach, combining molecular and immunological techniques, was investigated.
29
Pirie, Elizabeth Jane. "Factors affecting phoma stem canker severity in winter oilseed rape cultivars". Thesis, Imperial College London, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.498182.
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30
Eastmond, Peter J. "Carbon partitioning in developing embryos of oilseed rape (Brassica napus L.)". Thesis, University of East Anglia, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.266757.
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31
Simpson, Euan C. "The impact of herbicide tolerant oilseed rape in selected agro-ecosystems". Thesis, University of Glasgow, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.274117.
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32
Whytock, Gillian P. "The impact and control of broad-leaved weeds in oilseed rape". Thesis, University of Aberdeen, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.312653.
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Broad-leaved weeds have generally been dismissed as less competitive than grass weeds in oilseed rape and therefore their competitive effect on the crop has been ignored. This has limited the development of cost-effective strategies for their control. A survey identified the main weeds of winter oilseed rape in north-east Scotland as chickweed, annual meadowgrass, volunteer barley, mayweed spp., field pansy and shepherd's purse. Of these, only the effect of volunteer barley has been previously researched. Field trials over five years showed that the effects of broad-leaved weeds on the growth and yield of oilseed rape varied between seasons, but clearly demonstrated that these weeds can be very competitive and can cause substantial yield losses. The start of crop stem extension in spring was identified as the critical time for broad-leaved weed competition in oilseed rape. Unless the crop is free of weed competition at this time or is sufficiently vigorous to outgrow weeds, yield losses will result. However, autumn proved to be the optimum time to control broad-leaved weeds and early treatments were found to be most efficacious. The variation in crop response between seasons was largely attributable to seasonal weather and its effects on crop vigour and weed growth. Seasonal weather also influenced the efficacy of reduced doses of herbicides. Metazachlor gave good weed control at reduced doses in vigorous crops, but not in less vigorous crops in poor growing seasons. This variability makes it difficult to predict crops responses to weed competition and the justification for herbicides. Thus a semi-prophylactic approach is proposed, based on a reduced dose of metazachlor applied early with the option of a reduced dose follow-up post-emergence treatment in autumn, if necessary. This is a practical approach which could be adopted on many farms and would benefit the farmer in terms of improved cost-effectiveness and go some way towards satisfying the demand for reduced pesticide inputs.
33
Bruser, Marie. "A case for developmental genetics to increase yield of oilseed rape". Thesis, University of East Anglia, 2017. https://ueaeprints.uea.ac.uk/66971/.
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B. napus is a widely-grown crop and its uses are widespread. The seeds used mostly for oil production are contained within cylindrical fruits called pods. These strongly resemble the well-studied fruiting structures of the model plant Arabidopsis, in which patterning genes, hormones and cellular growth dynamics are well characterized. The ovary of the fruit is partitioned into two valves separated by the replum and the valve margin, which is required for fruit opening and seed dispersal. On the inside are the ovules, which post-fertilization develop into seeds. Of benefit for B. napus crop improvement would be the production of larger seeds as well as more seeds per pod. The aim of this work was to improve yield of oilseed rape by targeting fruit growth. To this end, the growth of the B. napus pod was described in detail. This formed the basis of the study as it is imperative to understand the entire fruiting structure before attempting any improvements. Fruit length correlated consistently with seed number, making it a valuable trait to study. A correlation between stomata density and fruit length was investigated using several members of the Brassicaceae. Next, to identify new genes contributing to pod growth, a genome-wide association study (GWAS) was carried out on a diverse B. napus population. This yielded DPb, a cell-cycle gene. Further analysis lead to the identification of TSN1, a gene with similar expression levels as the former. Functions of the DP/E2F family with TSN1 and TSN2 were then studied in detail in the Arabidopsis fruit. Results uncovered an overlapping function in seed development and fruit growth of these previously not associated genes. Overall, this work thus demonstrates how findings in a crop species can be translated to the model to increase the fundamental knowledge of biological processes.
34
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.
Pełny tekst źródła
35
Millam, Stephen. "Studies on the application of biotechnology to Brassica napus L". Thesis, University of Wolverhampton, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.328263.
Pełny tekst źródła
36
Batish, Suman. "Analysis of pathogenicity of Pyrenopeziza brassicae, cause of light leaf spot of brassicas". Thesis, University of Cambridge, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.240904.
Pełny tekst źródła
37
Bradburne, Robert Peter. "The formation and function of glucosinolates in Brassica napus". Thesis, University of East Anglia, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.327435.
Pełny tekst źródła
38
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/.
Pełny tekst źródłaStreszczenie:
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.
39
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.
Pełny tekst źródłaStreszczenie:
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.
40
Mitrousia, Georgia. "Effectiveness of resistance against Leptosphaeria species (phoma stem canker) in oilseed rape". Thesis, University of Hertfordshire, 2016. http://hdl.handle.net/2299/17228.
Pełny tekst źródłaStreszczenie:
To improve understanding of the effectiveness of host resistance against Leptosphaeria spp., three aspects of effectiveness of resistance were investigated. With focus on the major Rlm-mediated resistance against L. maculans, changes in effectiveness of Rlm7-mediated resistance to prevent initiation of disease epidemics at the leaf spot stage were investigated in winter oilseed rape field experiments at five sites in the UK over the period with the cropping seasons 2009/2010 - 2013/2014. L. maculans isolates virulent against Rlm7 were identified in the UK. This may be associated with observed changes in lesion phenotypes on the Rlm7 cultivars in field conditions. However, despite increased severity of phoma leaf spotting on Rlm7 cultivars, there was no associated increase in phoma stem canker severity at the end of the cropping seasons. The effectiveness of winter oilseed rape cultivars for control of phoma stem canker (caused by L. maculans or L. biglobosa) was affected by the coexistence of the two Leptosphaeria species in oilseed rape crops. Weather conditions influenced ascospore release of both species and favoured L. biglobosa ascospore release in 2011, resulting in subsequent increased L. biglobosa phoma leaf spotting and stem canker severity. However, coexistence of Leptosphaeria spp. on oilseed rape crops was affected by the cultivar resistance against L. maculans. CE experiments showed that there were interactions between the two Leptosphaeria spp. in planta. Their coexistence on B. napus was influenced by the different host responses that they trigger during host colonisation. Effects of increased temperature on effectiveness of resistance against L. maculans and on severity of symptoms by Leptosphaeria spp. on B. napus were investigated. Increased temperature affected both Rlm4- and Rlm7-mediated resistance, when assessed by phenotypic and molecular techniques. Increased temperature was associated with increased symptom severity, for both L. maculans and L. biglobosa lesions on plants. Cultivar quantitative resistance background increased effectiveness of resistance against phoma stem canker pathogens at increased temperature and should be deployed in in strategies for adaptation to climate change to avoid increased phoma stem canker epidemics in the future.
41
Furukawa-Stoffer, Tara Lee. "Characterization of triacylglycerol biosynthetic enzymes from microspore-derived cultures of oilseed rape". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape16/PQDD_0027/MQ38426.pdf.
Pełny tekst źródła
42
Jönsson, Martin. "Responses to oilseed rape and cotton volatiles in insect herbivores and parasitoids /". Alnarp : Dept. of Crop Science, Swedish Univ. of Agricultural Sciences, 2005. http://epsilon.slu.se/200514.pdf.
Pełny tekst źródła
43
Furukawa-Stoffer, Tara L., i University of Lethbridge Faculty of Arts and Science. "Characterization of triacylglycerol biosynthetic enzymes from microspore-derived cultures of oilseed rape". Thesis, Lethbridge, Alta. : University of Lethbridge, Faculty of Arts and Science, 1996, 1996. http://hdl.handle.net/10133/63.
Pełny tekst źródłaStreszczenie:
Particulate and solubilized preparations of phosphatidate (PA) phosphatase (EC 3.1.3.4) and dia-cylglycerol acyltransferase (DGAT, EC 2.3.1.20) from microspore-derived (MD) cultures of Brassica napus L. cv Topas were characterized. The activity of solubilized PA phosphatase decreased by about 50% following storage for 24 h
at 4 degrees celsius, whereas the activity of DGAT decreased by 30%. Bovine serum albumin increased the stability of both enzymes. Both preparations were enriched in the target enzyme and thus, may be useful in studies of regulation with limited influence by the other Kennedy pathway enzymes. Solubilized PA phosphatase was shown to dephosphoryolate a number of phosphate-containing compounds and showed a preference for dioleoyl-PA and dipalmitoyl-PA over other forms of PA tested. Microsomal PA phosphatase from MD embryos was partially dependent on Mg2+ and partially inhibited by the thioreactive agent, N-ethylmaleimide (NEM). The partial sensitivity to NEM suggest that MD embryos of B. napus may contain forms of PA phosphatase involved in glycerolipid synthesis and signal transduction. NEM-sensitive and NEM-insensitive PA phosphatase activity was found in microsomes of a cell suspension culture of B. napus L. cv Jet Neuf. PA phosphatase, solubilized from MD embryos, was partially purified using ammonium sulfate fractionation followed by anion exchange chromatography. PA phosphatase was resolved into two distinct peaks following anion-exchange chromatography. The peaks contained both NEM-sensitive and NEM-insensitive PA phosphatase activity. Following gel filtration, solubilized PA phosphatase displayed a minimum apparent Mr of about 40 000. Antibodies raised against partially purified preparations of PA phosphatase and DGAT from MD embryos of B. napus L. cv Topas were used in the development of immunochemical probes for these enzymes. Inhibitory anti-PA phosphatase antibodies were developed. Attempts were also made to identify a sub-class of antibodies which could interact with both denatured and native DGAT.xviii, 137 leaves : ill. ; 28 cm.
44
Boys, Emily Frances. "Resistance to Pyrenopeziza brassicae (light leaf spot) in Brassica napus (oilseed rape)". Thesis, University of Nottingham, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.556103.
Pełny tekst źródłaStreszczenie:
This project aimed to provide a greater understanding about resistance to Pyrenopeziza brassicae in oilseed rape. A doubled haploid population of Brassica napus derived from a cross between the resistant oilseed rape cultivar Imola and a susceptible breeding line was used to map a single major locus associated with resistance to P. brassicae. The locus was positioned at the end of the linkage group corresponding to chromosome A1, a region homeologous to Arabidopsis thaliana chromosome 3. The resistance was associated with a phenotype that involved reduced P. brassicae subcuticular hyphal growth, the collapse of epidermal cells and an absence of asexual sporulation. P. brassicae was, however, able to sporulate sexually on senescent leaf tissue of the resistant plants. For the doubled haploid population, there were significant correlations between severity of light leaf spot assessed on field plots in Hertfordshire and Scotland and severity assessed on seedlings in controlled environment conditions. Analysis using quantitative peR showed that the lines of the doubled haploid population differed in their ability to support the growth of P. brassicae in controlled environment (on cotyledons and young leaves) and field conditions. The resistance present in oil seed rape cultivar Imola is different from that observed in other B. napus cultivars/lines, where asexual sporulation was observed on even the least susceptible cultivars/lines, and currently appears stable in different parts of the UK. An improved understanding of resistance to P. brassicae in B. napus will help to inform decisions about the deployment of new resistant cultivars to maximise the durability of the resistance.
45
Murchie, Archie Kelso. "Parasitoids of cabbage seed weevil and brassica pod midge in oilseed rape". Thesis, Keele University, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.318159.
Pełny tekst źródłaStreszczenie:
Oilseed rape (Brassica napus (L. )), the second most important arable crop in the UK after cereals, is attacked during the summer by cabbage seed weevil Ceutorhynchus assimilis (Paykull) and brassica pod midge Dasineura =brassicae (Winnertz). In mainland Europe, these two 'pests are known to be attacked by a range of hymenopteran parasitoids but virtually nothing is known about their parasitoids in the UK. This study found that the ectoparasitic Trichomalus perfectus (Walker) (Pteromalidae) was the most abundant species attacking C. assimilis, achieving, in unsprayed crops, levels of parasitism up to 73%. The egg-larval Platygaster subuliformis Kieffer (Platygastridae) was reared from D. brassicae for the first time and is probably a new species record for the UK; it was the most abundant species attacking the midge in winter rape. The endoparasitic Omphale clypealis (Thomson) (Eulophidae) was the most abundant species attacking D. brassicae in spring rape. The complexity of assessing parasitism in the multivoltine D. brassicae is discussed. In-field temporal and spatial distributions of hosts and parasitoids were studied using a novel randomization test and the results related to known biological characteristics of species. Using a new design of insect flight trap, P. subuliformis was shown to respond to 2-phenylethyl isothiocyanate and O. clypealis to 2-propenyl isothiocyanate, both volatile secondary plant compounds, produced by brassicaceous plants on damage. Field trials demonstrated that the post-flowering application of the organophosphate insecticide triazophos, has a detrimental effect on T. perfectus, killing adults and larvae, whereas the synthetic pyrethroid alphacypermethrin was less harmful because it was applied before the main migration of T. perfectus into the crop. The importance of the parasitoids ' of rape pests to integrated protection strategies for the crop are discussed.
46
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/.
Pełny tekst źródłaStreszczenie:
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.
47
Jenkins, Elizabeth. "Polygalacturonase gene expression during pod development in oilseed rape (Brassica napus L.)". Thesis, University of Nottingham, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.284426.
Pełny tekst źródła
48
Toroser, Dikran. "Aspects of glucosinolate biosynthesis in oilseed rape pods, pod-walls and seeds". Thesis, University of Newcastle Upon Tyne, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.384832.
Pełny tekst źródła
49
Dunlop, Gordon. "Linking germination traits of oilseed rape (Brassica napus L.) to DNA markers". Thesis, Abertay University, 2000. https://rke.abertay.ac.uk/en/studentTheses/22973d1e-546d-4238-9ed8-32a4403f3a52.
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Oilseed rape has become an important weed in arable rotations and a feral plant of field margins, soil dumps and roadsides. Seed persistence in the soil following induced secondary dormancy is thought to perpetuate these weed and feral populations. Potential variation between cultivars has been suggested in previous work in the extent of secondary dormancy and other germination traits, and in underlying genetic heterogeneity. The aim of this work was to quantify in more detail inter- and intra- cultivar variation in germination traits for six oilseed rape cultivars, to confirm that variation was consistent in laboratory and field, and to ascertain whether there is a genetic base to this variation. The cultivars are Askari, Bristol, Gazelle, Libravo, Martina and Rocket, selected on the basis of their suspected heterogeneity. Laboratory germination tests were conducted at 4°C, 10°C and 19°C on a thermal plate and confirmed substantial inter-cultivar variation in germination rate, induction of secondary dormancy and the temperature stimuli required for dormancy break. The phenotypic traits were quantified by mathematical parameters and cultivars ranked in order of decreasing heterogeneity. DNA analysis was made on leaf tissue of early, middle and late germinating phenotypes using two simple sequence repeat primers. There was heterogeneity and phenotypic variability generally, but a direct association between phenotype and genotype was found only in the cultivar Martina. Field emergence trials revealed non-linearity in emergence and a strong similarity between laboratory germination and field emergence curves. Cultivar heterogeneity was found to be similar for emergence rate and post-winter emergence. Again there was evidence of an association between heterogeneity in emergence and genetic heterogeneity in the DNA markers. The results suggest that standard seed testing should be carried out at low temperatures to detect any hidden variability in germination. Plant breeders should be cautious about introducing variability into new breeding lines as this might increase the potential persistence of feral populations and the risk of gene transfer to later.
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Loudon, Peter T. "Somatic hydridisation within the genus Brassica". Thesis, University of Cambridge, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.306453.
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