Letteratura scientifica selezionata sul tema "Seedling resistance"
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Articoli di riviste sul tema "Seedling resistance"
1
Milus, Eugene A., Kevin D. Lee e Gina Brown-Guedira. "Characterization of Stripe Rust Resistance in Wheat Lines with Resistance Gene Yr17 and Implications for Evaluating Resistance and Virulence". Phytopathology® 105, n. 8 (agosto 2015): 1123–30. http://dx.doi.org/10.1094/phyto-11-14-0304-r.
Testo completoAbstract (sommario):
Stripe rust, caused by Puccinia striiformis f. sp. tritici, has been the most important foliar wheat disease in south central United States since 2000 when a new strain of the pathogen emerged. The resistance gene Yr17 was used by many breeding programs to develop resistant cultivars. Although Yr17 was classified as a seedling (all-stage) resistance gene conferring a low infection type, seedlings with Yr17 frequently had intermediate to high infection types when inoculated with isolates that caused little or no disease on adult plants of the same wheat lines. The objectives of this study were to determine how to best evaluate Yr17 resistance in wheat lines and to determine which factors made seedling tests involving Yr17 so variable. Stripe rust reactions on wheat seedlings with Yr17 were influenced by temperature, wheat genotype, pathogen isolate, and the leaf (first or second) used to assess the seedling reaction. The most critical factors for accurately evaluating Yr17 reactions at the seedling stage were to avoid night temperatures below 12°C, to use the first leaf to assess the seedling reaction, to use multiple differentials with Yr17 and known avirulent, partially virulent and virulent isolates as controls, and to recognize that intermediate infection types likely represent a level of partial virulence in the pathogen that is insufficient to cause disease on adult plants in the field.
2
Blaker, N. S., e J. D. Hewitt. "Comparison of Seedling and Mature Plant Resistance to Phytophthora parasitica in Tomato". HortScience 22, n. 1 (febbraio 1987): 103–5. http://dx.doi.org/10.21273/hortsci.22.1.103.
Testo completoAbstract (sommario):
Abstract Seedlings of 11 genotypes of tomato (Lycopersicon esculentum, Mill.) were inoculated at the first true leaf stage with zoospores of Phytophthora parasitica under controlled conditions and evaluated for resistance based on seedling death. The same lines also were transplanted into two fields naturally infested with P. parasitica and grown to maturity. Disease severity in the field was evaluated based on plant death and canopy collapse prior to harvest. Resistance to P. parasitica was present in both commercial lines and accessions of L. esculentum var. cerasiforme (Dun.) A. Gray. Seedling resistance was generally a good predictor of resistance in mature plants. The relative resistance and susceptibility expressed in seedlings was reflected in 10 of 11 genotypes in the field. One cultivar that was susceptible in the seedling test appeared resistant in the field. Expression of resistance in both the seedling test and field was influenced by environmental factors.
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Abdelmalik, Abdelmalik M. "Enhanced Growth and Drought Resistance in Seedlings of Acacia tortilis due to Inoculation of Arbuscular Mycorrhiza Fungi and Bacillus subtilis". International Journal of Agriculture and Biology 26, n. 06 (1 dicembre 2021): 750–60. http://dx.doi.org/10.17957/ijab/15.1891.
Testo completoAbstract (sommario):
A shade house experiment was conducted in Saudi Arabia to evaluate the impact of a mixture of three arbuscular mycorrhiza fungi (AMF) namely Funneliformis mosseae, Rhizophagus intraradices and Claroideoglomus etunicatum, a bacterium Bacillus subtilis, and their combinations on the growth and drought resistance potential of Acacia torilis seedlings under moderate and water deficit-stress. Thus, inoculants treatments (AMF, Bacillus subtilis, AMF+Bacillus, and control) and several watering intervals (1, 2, 3 and 4 weeks) were applied. Inoculation of AMF and Bacillus to A. tortilis seedlings found effective in terms of improved seedling growth. AMF and combined inoculation resulted in a larger shoot (shoot fresh and dry weights, seedling height, leaf number, leaf area) and root development (root fresh and dry weights, root length, root surface area, and root volume) as compared to the non-inoculated seedlings. Single inoculants of B. subtilis, showed better improvement in 1- and 2-week watering intervals compared to the control. Inoculated seedlings showed lower proline accumulation than non-inoculated seedlings, and thus improved seedling resistance to water deficit-stress. Mycorrhizal and mixed inoculation enhanced the amount of chlorophyll in the seedling’s leaves. Furthermore, seedlings with AMF and co-inoculants showed better drought tolerance even at 3- and 4-week watering intervals. © 2021 Friends Science Publishers
4
Zhao, Wen Ju, Li Rong Wang, Hong Ji, Jian Shu Song e Yan Wei Fan. "Impacts of Plant Additive on the Seedling Bricks’ Physical Properties". Advanced Materials Research 518-523 (maggio 2012): 5401–5. http://dx.doi.org/10.4028/www.scientific.net/amr.518-523.5401.
Testo completoAbstract (sommario):
Homemade seedling bricks, which mixed and suppressed with the plant additive, clay, compost, slow-release fertilizer, can create a good living environment for plant growth, guide the development and growth of plant roots, achieve integration of bricks and seedlings to plant, and the seedlings transplant without time limit. We tested the molding density, shatter resistance, seepage rate and other physical properties of seedling bricks without plant additive, adding 5% and 10% of wheat straw, wheat shells and corn leaves, and the results show that adding plant additive can improve the physical properties of the seedling bricks effectively. The minimum density of the seedling brick contains 10% corn leaves, the minimum shatter resistance of the seedling brick contains 10% wheat straw, and the maximum seepage rate of the seedling brick contains 10% wheat straw.
5
Duchesne, Luc C., R. L. Peterson e Brian E. Ellis. "Interaction between the ectomycorrhizal fungus Paxillus involutus and Pinus resinosa induces resistance to Fusarium oxysporum". Canadian Journal of Botany 66, n. 3 (1 marzo 1988): 558–62. http://dx.doi.org/10.1139/b88-080.
Testo completoAbstract (sommario):
Inoculation of Pinus resinosa Ait. seedlings with the ectomycorrhizal fungus Paxillus involutus Fr. resulted in a 47% increase in resistance to subsequent infection by the root pathogenic fungus Fusarium oxysporum f.sp. pini as compared with control seedlings. This increase in seedling survival was associated with a sixfold decrease in the sporulation of F. oxysporum in the rhizosphere of seedlings inoculated with Pax. involutus when compared with the rhizosphere of control seedlings. Extraction and bioassay of the seedling rhizosphere and seedling tissues indicated that inoculation with Pax. involutus led to a fivefold increase in antibiotic activity in the rhizosphere of the seedlings treated with Pax. involutus. Most or all of the fungitoxicity was localized in the rhizosphere. Disease suppression by Pax. involutus in P. resinosa is, therefore, associated with an increase of fungitoxic chemicals in the rhizosphere of seedlings.
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Lu, Pengxin, e Darren Derbowka. "Effects of seedling age on blister rust resistance assessments in eastern white pine and its hybrid backcrosses". Canadian Journal of Forest Research 42, n. 1 (gennaio 2012): 67–74. http://dx.doi.org/10.1139/x11-164.
Testo completoAbstract (sommario):
Seedling age at the time of artificial white pine blister rust ( Cronartium ribicola J.C. Fisch.) inoculation can affect the duration and accuracy of resistance assessments for eastern white pine ( Pinus strobus L.) and its hybrid backcrosses and thereby affect advances in breeding programs intended to enhance genetic resistance to the pathogen. Based on postinoculation seedling mortality rates, up to 5 years were required to rank resistance of eastern white pine genotypes when seedlings were inoculated with C. ribicola at 2 years of age compared with less than 2 years when they were inoculated after the first growing season. In this study, we evaluated and compared consistency of genotype rankings in seedling mortality rates between the two inoculation approaches. Assessment results from inoculating seedlings after the first growing season proved as reliable as those achieved by inoculating them after the second growing season. Inoculating seedlings at a younger age not only substantially reduced experimental time and costs but also allowed a larger number of seedlings to be screened for resistance, leading to higher experimental precision.
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Bodnaryk, R. P., e R. J. Lamb. "Influence of seed size in canola, Brassica napus L. and mustard, Sinapis alba L., on seedling resistance against flea beetles, Phyllotreta cruciferae (Goeze)". Canadian Journal of Plant Science 71, n. 2 (1 aprile 1991): 397–404. http://dx.doi.org/10.4141/cjps91-055.
Testo completoAbstract (sommario):
Seedlings of Brassica napus L. 'Westar' or Sinapis alba L. 'Ochre' grown from seeds of various size were offered to flea beetles, Phyllotreta cruciferae (Goeze) in feeding tests for damage assessment. The proportion of cotyledon area damaged in both species was highest for seedlings grown from small seeds in choice and no-choice feeding tests. The proportion of seedlings killed by flea beetle feeding was also highest in seedlings from small seeds, an effect that was especially pronounced at high beetle densities (10/seedling) where 100% of seedlings from small seeds of B. napus were killed compared to 28.3% of seedlings from big seeds. For S. alba, at 20 beetles/seedling, 45.4% of seedlings from small seeds were killed compared to only 9.1% of seedlings from big seeds. Seedlings grown from big seeds of S. alba tolerated low levels of damage caused by flea beetle feeding or by scissors. No evidence for tolerance was obtained for seedlings from small seeds of S. alba or for seedlings from big or small seeds of B. napus. "Big seeds" appears to be a desirable trait that enhances crucifer seedling resistance to flea beetle attack and results in increased seedling survival. Key words: Brassica napus 'Westar', Sinapis alba 'Ochre', Phyllotreta cruciferae, flea beetle, seed size, resistance
8
Cséplö, M., M. Csösz, M. Gál, O. Veisz e G. Vida. "Seedling resistance to Stagonospora nodorum blotch in wheat genotypes". Czech Journal of Genetics and Plant Breeding 49, No. 2 (16 maggio 2013): 77–85. http://dx.doi.org/10.17221/69/2011-cjgpb.
Testo completoAbstract (sommario):
In two independent experiments set up in the greenhouse the seedling resistance to Stagonospora nodorum blotch was investigated in 92 varieties, breeding lines and genotypes with a known genetic background. The greatest area under the disease progress curve calculated from lesion type was 37.06, while in the case of the most resistant genotype this value was 0.38. Many of the lines and varieties bred in Martonvásár proved to have excellent resistance in terms of both percentage of infected leaf area and lesion type. Observations indicate that, depending on the aim of the experiment, the efficient selection of breeding lines is possible in the seedling stage either on the basis of the area under the disease progress curve calculated for lesion types, or on the basis of lesion types scored 7, 11 or 14 days after inoculation.
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Putnik-Delic, Marina. "Resistance of some wheat genotypes to Puccinia triticina". Zbornik Matice srpske za prirodne nauke, n. 115 (2008): 51–57. http://dx.doi.org/10.2298/zmspn0815051p.
Testo completoAbstract (sommario):
Thirty-four wheat genotypes were tested for resistance characteristics to Puccinia triticina at different growth stages. At seedling stage in a greenhouse, latency period, infection frequency and reaction type were determined. In the field, time of spike appearance, and infection intensity were followed. Weak (r = 0.322) to strong (r = 0.660) correlation was found between resistance characteristics at seedling stage (LPxIFxRT, in the greenhouse) and in adult plants (infection intensity and AUDPC, in the field). The values of AUDPC (area under the disease progress curve) were also strongly related to resistance characteristics of seedlings (r = 0.598). As pseudoresistant in the field (especially equal to adult plant resistance) according to other stresses reactions were considered genotypes which were the most sensitive at seedling stage (20?C) and at adult stage they did not express maximal infection intensity, particullar Evropa 90 and Suvaca. Adult plant resistance as the sum of specific and pseudoresistance was observed on genotypes Tiha, Zlatka and Eva.
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Admassu-Yimer, Belayneh, Tyler Gordon, Stephen Harrison, Shahryar Kianian, Harold Bockelman, J. Michael Bonman e Kathy Esvelt Klos. "New Sources of Adult Plant and Seedling Resistance to Puccinia coronata f. sp. avenae Identified among Avena sativa Accessions From the National Small Grains Collection". Plant Disease 102, n. 11 (novembre 2018): 2180–86. http://dx.doi.org/10.1094/pdis-04-18-0566-re.
Testo completoAbstract (sommario):
Accessions of cultivated oat (Avena sativa L.) from the United States Department of Agriculture–Agricultural Research Service Small Grains Collection in Aberdeen, ID were characterized for adult plant resistance (APR) and seedling resistance to crown rust, caused by Puccinia coronata f. sp. avenae. Initially, 607 oat accessions with diverse geographic origins were evaluated in field tests in Baton Rouge, LA. Of those, 97 accessions were not fully susceptible and were tested in the field in St. Paul, MN against a diverse P. coronata f. sp. avenae population. Thirty-six accessions that had some level of resistance in both field tests and mean coefficients of infection of ≤20 were further evaluated for APR and seedling resistance. Among these, four accessions (PI 193040, PI 194201, PI 237090, and PI 247930) were resistant to eight P. coronata f. sp. avenae races as seedlings. Twenty-nine accessions had resistance to at least one of the P. coronata f. sp. avenae races. Three accessions (CIav 2272, CIav 3390, and PI 285583) were fully susceptible to all eight P. coronata f. sp. avenae races as seedlings. Further evaluation of the three seedling-susceptible accessions at the flag leaf stage in a growth chamber resulted in moderately susceptible to moderately resistant responses. The resistance sources presented here may contain genes not deployed in elite oat varieties, and may be useful for future crown rust resistance breeding. The adult and seedling resistance found in accessions of the cultivated oat species is especially valuable because it avoids problems associated with the transfer of genes from wild species to cultivated oat.
Tesi sul tema "Seedling resistance"
1
Morse, Stephen. "The role of hydroxamic acids in conferring resistance to aphid pests of seedling maize (Zea mays)". Thesis, University of Southampton, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.293605.
Testo completo
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Lorentz, Andrew. "Design, construction and testing of an ascending micropenetrometer to measure soil crust resistance". Thesis, Cranfield University, 2014. http://dspace.lib.cranfield.ac.uk/handle/1826/8511.
Testo completoAbstract (sommario):
The increasing world population is putting pressure on global food production.
Agriculture must meet these growing demands by increasing crop yields. One phenomenon
which prevents seedling emergence and damages crop yield is soil crusting. Understanding
of soil crusting and the factors which influence it is fundamental to ensuring good crop
production. An instrument which will test soil crust strength in a novel way, mimicking
seedling growth, may lead to pre-emptive agricultural soil management which could
increase crop production. This work details the process of design, construction and testing
of an ascending penetrometer to measure soil crust strength. The full design process is
discussed from concept generation and evaluation, using experimental methods and a
multi-criteria decision making tool, through to final design configuration, specification,
manufacture and testing.
Traditionally, soil penetrometers measure soil strength by forcing a probe from the surface
of the soil into the bulk soil below. To more accurately measure the direct impedance a
seedling would experience a device should measure impedance from the bulk soil upwards
and into the soil crust, mimicking what a growing seedling would experience. Results
prove that the manufactured ascending penetrometer with a force resolution of 0.01N and
displacement resolution of 0.0004mm is capable of detecting differences in soil crusts. At
these resolutions and accuracy to 0.1N and 0.1mm excellent repeatability was achieved.
The machine is therefore a useful and realistic tool for quantitatively comparing soil crusts
in soil. It is hoped that being able to compare soil crust strength will lead to improved soil
management techniques.
3
Malligan, Cassandra D. "Crown rot (fusarium pseudograminearum) symptom development and pathogen spread in wheat genotypes with varying disease resistance". University of Southern Queensland, Faculty of Sciences, 2009. http://eprints.usq.edu.au/archive/00006225/.
Testo completoAbstract (sommario):
[Abstract]Crown rot, caused by Fusarium pseudograminearum (Fpg), is an important soilborne disease of wheat and barley. The degree of crop damage depends on seasonal conditions. Typically, high moisture conditions early in the season encourage seedling infection from stubble residues. Moisture stress later in the season leads to the production of unfilled “whiteheads”. Current control relies on cultural practices and sowing of partially resistant varieties. In order to understand the nature of partial resistance, I have examined the patterns of disease symptom development and pathogen spread in susceptible and partially resistant tissues of both pot-grown wheat, barley and oat seedlings and field-grown inoculated wheat trials. Further research was conducted to determine whether differences in pathogenicity occur amongst a small subset of Australian Fpg isolates. Seedling experiments confirmed that differences in disease ratings between susceptible and partially resistant genotypes are detected in younger leaf sheaths of older seedlings. At later harvest times differences between these genotypes are not significant in older leaf sheaths. Re-isolation of Fpg from inoculated seedlings has shown that each tissue was infected later in partially resistant genotypes compared to susceptible ones with a significantly lower number of isolations recorded at each harvest time in 42 day old seedlings. Barley cultivars were rapidly infected by the pathogen and exhibited high levels of disease symptoms. By comparison levels of infection in oats were low compared to all other genotypes. No significant differences between genotypes were observed in coleoptile tissues, either in fungal colonisation or development of disease symptoms. Disease development in the subcrown internode varied between lines/cultivars but was not representative of the relative susceptibility of each genotype. The pathogen did not appear to invade plant tissue via the vascular system but rather spread directly across the stem from leaf sheath to leaf sheath. Field trials were designed to study disease symptom development and localisation of Fpg hyphae in all expanded tissues (excluding head and roots) in wheat genotypes of known susceptibility to crown rot. Plants were harvested at approximately fortnightly intervals throughout the growing season. The main effects and interactions of harvest, genotype and tiller on each plant part were examined with a detailed statistical analysis of differences seen in these factors between susceptible and partially resistant wheat genotypes, in two inoculated field trials. While differences between genotypes were mostly not significant at each harvest when disease rating or isolations from leaf sheath tissues were examined, important differences between susceptible and resistant genotypes were seen in disease developments and Fpg infections of stem tissue in field trials. Restriction of pathogen growth and symptom development was more pronounced in the tissues of 2-49 (possesses seedling resistance) than in the field resistant Sunco. At present, the mechanisms that lead to these resistance responses are unknown. The pathogenicity study aimed to determine whether 7 Fpg isolates and a mixed inoculum differed in ability to cause crown rot in 9 wheat genotypes ranging in susceptibility to this disease. Although a genotype*inoculum interaction was significant, there is no evidence of stable pathogenic races in the isolates examined in these experiments. The growth of all isolates was partially inhibited in a consistent manner on resistant genotypes when compared to very susceptible genotypes. These results confirm significant differences in the aggressiveness of Fpg isolates on wheat, evidenced by variation in mean disease severity between isolates growing on a range of host genotypes.
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Sandhu, Karanjeet Singh. "Genetic and molecular analyses of barley for seedling and adult plant resistance against rust diseases". Thesis, The University of Sydney, 2011. http://hdl.handle.net/2123/8860.
Testo completoAbstract (sommario):
Genetic studies were carried out to determine the inheritance of unknown seedling resistance (USR) to leaf rust (caused by Puccinia hordei Otth.) in the barley cultivar Ricardo. In the greenhouse Ricardo/Gus F3 (187 lines) and BC1F2 (130 lines) populations based studies using an array of P. hordei pathotypes (pts), revealed that the USR in Ricardo was conferred by a single dominant gene, which was tentatively named RphRic. Bulk segregant analysis (BSA) of the F3 population using a multiplex-ready PCR technique mapped RphRic on chromosome 4H flanked by markers GBM1220 and GBM1003 at distances of 17.4 cM and 20.4 cM, respectively. Being the first gene for leaf rust resistance mapped on chromosome 4H, RphRic was catalogued as Rph21. Phenotyping of Ricardo/Peruvian (Rph2) F3 populations and genotyping of both parents using the Rph2-linked marker ITS1 confirmed the presence of Rph2 in Ricardo. The Ricardo/Gus F3 and BC1F2 populations segregated for the presence of an additional gene when tested under field conditions using the same pathotype (pt), 5457P+ (used in greenhouse). This uncharacterised adult plant resistance (APR) against P. hordei, found in Ricardo, appeared to be distinct from Rph20 when genotyped using a closely linked marker bPb-0837. Responses of 113 advanced breeding lines and cultivars of barley (Hordeum vulgare L. subsp. vulgare), along with the susceptible control genotype Gus, were assessed against P. hordei pts in the greenhouse at seedling and field at adult plant growth stages. The tests revealed the presence of APR in 68 lines, USR in 23 lines and the seedling resistance gene Rph3 in three lines. Marker bPb-0837 was present in 35 of the 68 lines carrying APR, which suggested that these 35 lines carry APR gene Rph20. The remaining 33 lines, which lacked the Rph20 linked marker, likely carry new sources of APR. Pedigree analysis of the 68 lines found to carry APR revealed that 32 were related to cultivar (cv.) Gull and to H. laevigatum, two were related to cv. Bavaria and one related to cvv. Manchuria and Taganrog. Ancestral pedigree analysis also revealed the common presence of cv. Diamant (X-ray mutant) in the parentage of lines likely carrying Rph20. The remaining 19 lines lacked detectable seedling resistance and were susceptible in the field at adult plant growth stages. Four international barley nurseries comprising 820 lines with 579 unique pedigrees were sourced from the International Centre for Agricultural Research in the Dry Areas (ICARDA) and analysed for resistance against isolates of P. hordei, P. graminis f. sp. tritici (Pgt) and barley grass stripe rust (BGYR). Overall analyses of the responses of 783 lines (excluding 37 missing lines) to P. hordei showed that 728 (93%) carried the major seedling resistance gene Rph3, five (0.65%) carried USR, six (0.75%) carried uncharacterised APR and 44 (5.6%) lines were susceptible at all growth stages. Of the six lines identified with uncharacterised APR, three likely carried Rph20 based on the presence of the Rph20-linked marker bPb-0837. Based on tests with several control genotypes, marker bPb-0837 was found to be more reliable than Ebmag0833 in detecting the presence of Rph20. All lines were resistant to Pgt pt 98-1,2,3,5,6 when tested as seedlings in the greenhouse. Out of the 783 lines tested, 164 produced immune responses, 284 produced resistant (1= to 3) responses and 335 produced mesothetic (X type) responses against pt 98-1,2,3,5,6. All but two 783 lines were highly resistant to BGYR in greenhouse tests, showing immune responses. The usefulness of 148 simple sequence repeats (SSRs) in revealing variability among Australian isolates of P. hordei were assessed. The markers comprised 71 developed for Pgt, 40 developed for P. triticina (Pt) and 37 developed for P. coronata f. sp. avenae (Pca). SSRs were tested across 22 pts of P. hordei from Australasia including one isolate of each of the control pathogens [Pt, Pgt, P. striformis f. sp. tritici (Pst), BGYR and P. graminis f. sp. avenae (Pga)]. Genotyping of P. hordei was also conducted with the PCR-fingerprinting primers M13 and (GACA)4. The SSRs developed from Pgt and Pt showed 100% cross amplification in P. hordei, while only nine Pca SSRs showed amplification in P. hordei. Of the 148 markers tested, only two Pgt SSRs (F4-15 and F7-22) were polymorphic. Both PCR-fingerprinting primers revealed polymorphisms among the isolates, with (GACA)4 generating the most informative fragments. Both SSRs and PCR fingerprinting markers out grouped the control pathogens Pt, Pgt, Pst, BGYR and Pga from the P. hordei pts. Polymorphic information content (PIC) values of SSR markers F4-15 and F7-22 were calculated as 0.50 and 0.55 respectively. Molecular analyses revealed evidence of clonal lineages among the P. hordei pts, supporting the hypothesis that some of the pts arose from mutational changes in the virulence of a founder pt. Sexual recombination within P. hordei in Australia on the alternate host Ornithogalum umbellatum may have resulted in some new pts with different virulence against Rph genes. This is the first study of Australasian pts of P. hordei using PCR-fingerprinting technique and SSR genotyping.
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Dugo, Tesfaye Letta <1976>. "Association mapping of stem rust resistance in durum wheat at the seedling and adult plant stages". Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2013. http://amsdottorato.unibo.it/5935/1/Dugo_Tesfaye_tesi.pdf.
Testo completoAbstract (sommario):
In wheat, stem rust is known to rapidly evolve new virulence to resistance genes. While more than 50 stem rust resistance (Sr) loci have been identified in wheat, only a few remain effective, particularly against the highly virulent race Ug99 (TTKSK race) and a mixture of durum-specific races. An association mapping (AM) study based on 183 durum wheat accessions was utilized to identify resistance loci for stem rust response in Ethiopia over four seasons and artificial inoculation with Ug99 (TTKSK race) and a mixture of durum-specific races under field conditions as well as in greenhouse test at seedling stage under controlled conditions for resistance to four highly virulent stem rust races: TRTTF, TTTTF, (TTKSK (Ug99) and JRCQC. The panel was profiled with 1,253 SSR and DArT markers. Twelve QTL-tagging markers were significant (P < 0.05) across three to four seasons. The role of Sr13, Sr9, Sr14, Sr17, and Sr28 was confirmed. Thirteen significant markers were in regions with no Sr genes/QTLs.
The results under controlled conditions showed that 15, 20, 19 and 19 chromosome regions harbored markers that showed significant effects for races TRTTF, TTTTF, TTKSK and JRCQC, respectively. These genomic regions showed marker R2 values ranging from 1.13 to 8.34, 1.92 to 17.64, 1.75 to 23.12 and 1.51 to 15.33% for races TRTTF, TTTTF, TTKSK and JRCQC, respectively. The study demonstrates that stem rust resistance in durum wheat is governed in part by shared loci and in part by race-specific ones. The QTLs identified in this study through AM will be useful in the marker-assisted development of durum wheat cultivars with durable stem rust resistance.
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Dugo, Tesfaye Letta <1976>. "Association mapping of stem rust resistance in durum wheat at the seedling and adult plant stages". Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2013. http://amsdottorato.unibo.it/5935/.
Testo completoAbstract (sommario):
In wheat, stem rust is known to rapidly evolve new virulence to resistance genes. While more than 50 stem rust resistance (Sr) loci have been identified in wheat, only a few remain effective, particularly against the highly virulent race Ug99 (TTKSK race) and a mixture of durum-specific races. An association mapping (AM) study based on 183 durum wheat accessions was utilized to identify resistance loci for stem rust response in Ethiopia over four seasons and artificial inoculation with Ug99 (TTKSK race) and a mixture of durum-specific races under field conditions as well as in greenhouse test at seedling stage under controlled conditions for resistance to four highly virulent stem rust races: TRTTF, TTTTF, (TTKSK (Ug99) and JRCQC. The panel was profiled with 1,253 SSR and DArT markers. Twelve QTL-tagging markers were significant (P < 0.05) across three to four seasons. The role of Sr13, Sr9, Sr14, Sr17, and Sr28 was confirmed. Thirteen significant markers were in regions with no Sr genes/QTLs.
The results under controlled conditions showed that 15, 20, 19 and 19 chromosome regions harbored markers that showed significant effects for races TRTTF, TTTTF, TTKSK and JRCQC, respectively. These genomic regions showed marker R2 values ranging from 1.13 to 8.34, 1.92 to 17.64, 1.75 to 23.12 and 1.51 to 15.33% for races TRTTF, TTTTF, TTKSK and JRCQC, respectively. The study demonstrates that stem rust resistance in durum wheat is governed in part by shared loci and in part by race-specific ones. The QTLs identified in this study through AM will be useful in the marker-assisted development of durum wheat cultivars with durable stem rust resistance.
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Pogoda, Maria [Verfasser], Jochen C. [Gutachter] Reif e Ralph [Gutachter] Panstruga. "Identification and validation of seedling powdery mildew resistance genes / Maria Pogoda ; Gutachter: Jochen C. Reif, Ralph Panstruga". Halle (Saale) : Universitäts- und Landesbibliothek Sachsen-Anhalt, 2019. http://d-nb.info/1210730200/34.
Testo completo
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Ellis, Margaret Lee. "The Soybean Seedling Disease Complex: Pythium spp. and Fusarium graminearum and their Management through Host Resistance". The Ohio State University, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=osu1322495401.
Testo completo
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Weerasooriya, Dilooshi Kumari. "Genetic analysis of interveinal chlorosis and reduced seedling vigor as related to agronomic performance in sorghum resistant to ALS inhibitor herbicides". Diss., Kansas State University, 2016. http://hdl.handle.net/2097/32896.
Testo completoAbstract (sommario):
Doctor of PhilosophyDepartment of Agronomy
Tesfaye T. Tesso
The lack of effective post-emergence weed control options is often highlighted as one of the major factors behind dwindling acreage under sorghum (Sorghum bicolor (L.) Moench) in the United States. The discovery of herbicide resistance sources in wild sorghum population and subsequent efforts to incorporate them into cultivated sorghum was received with much optimism to change weed management practices in sorghum. As the development of the technology advances, especially of the Acetolactate synthase (ALS) resistance, concerns over the temporary interveinal chlorosis and reduced seedling vigor in some of the resistant families became heightened. This thesis research is designed to shed light on the genetic basis of seedling chlorosis and assess its impacts on yield potential. The study has three parts; the first part is focused on identifying the genetic causes and plant mechanisms associated with the chlorotic phenotype. ALS herbicide resistant sister-lines expressing normal and chlorotic phenotypes were analyzed via RNA sequencing at four time points during seedling growth. The study identified several variants of genes coding chloroplast precursors and those that cause epigenetic modifications. Once confirmed, genetic markers can be developed to track these gene variants in the breeding population and eliminate segregates genetically prone to chlorosis/yellowing. The second part of the study focuses on assessing the effect of ALS resistance associated chlorosis on agronomic and nutritional parameters of sorghum inbred lines. A set of ALS resistant lines expressing different levels of the chlorotic phenotype were evaluated in replicated field trials and laboratory methods. Results showed that interveinal chlorosis delays flowering but does not have negative effect on yield and nutritional parameters with and without herbicide treatment. The last part addresses whether there is any yield drag that may be associated with herbicide resistance traits and foliar interveinal chlorosis. For this, we synthesized a large set (182) of hybrids from ALS resistant, ACCase resistant and regular (susceptible) seed and pollinator parents. The hybrids were then evaluated in three sets at multiple locations during the 2014 and 2015 crop seasons along with commercial checks. The results revealed that resistance to both herbicides do not cause any drag to grain yield. The traits also do not have any negative impact on grain and nutritional quality of resistant hybrids.
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Kalia, Bhanu. "Mining the Aegilops tauschii gene pool: evaluation, introgression and molecular characterization of adult plant resistance to leaf rust and seedling resistance to tan spot in synthetic hexaploid wheat". Diss., Kansas State University, 2015. http://hdl.handle.net/2097/18934.
Testo completoAbstract (sommario):
Doctor of PhilosophyGenetics Interdepartmental Program
Bikram S. Gill
Leaf rust, caused by fungus Puccinia triticina, is an important foliar disease of wheat worldwide. Breeding for race-nonspecific resistant cultivars is the best strategy to combat this disease. Aegilops tauschii, D genome donor of hexaploid wheat, has provided resistance to several pests and pathogens of wheat. To identify potentially new adult plant resistance (APR) genes, 371 geographically diverse Ae. tauschii accessions were evaluated in field with leaf rust (LR) composite culture of predominant races. Accessions from Afghanistan only displayed APR whereas both seedling resistance and APR were common in the Caspian Sea region. Seventeen accessions with high APR were selected for production of synthetic hexaploid wheat (SHW), using ‘TetraPrelude’ and/or ‘TetraThatcher’ as tetraploid parents. Six SHWs were produced and evaluated for APR to LR and resistance to tan spot at seedling stage. Genetic analysis and mapping of APR introgressed from accession TA2474 was investigated in recombinant inbred lines (RIL) population derived from cross between SHW, TA4161-L3 and spring wheat cultivar, ‘WL711’. Genotyping-by-sequencing approach was used to genotype the RILs. Maximum disease severity (MDS) for LR was significantly correlated among all experiments and APR to LR was highly heritable trait in this population. Nine genomic regions significantly associated with APR to LR were QLr.ksu-1AL, QLr.ksu-1BS, QLr.ksu-1BL.1, QLr.ksu-1BL.2, QLr.ksu-2DS, QLr.ksu-2DL, QLr.ksu-5AL, QLr.ksu-5DL and QLr.ksu-6BL. Association of QLr.ksu-1BL.1 with marker Xwmc44 indicated this locus could be slow-rusting APR gene, Lr46/Yr29. QTLs detected on 2DS, 2DL and 5DL were contributed by TA4161-L3 and are novel, along with QLr.ksu-5AL. Tan spot, caused by necrotrophic fungus, Pyrenophora tritici-repentis, has recently emerged as a damaging disease of wheat worldwide. To identify QTLs associated with resistance to Race 1 of P. tritici-repentis, F[subscript]2:3 population derived from cross between SHW, TA4161-L1 and winter wheat cultivar, ‘TAM105’ was used. Two major effect QTLs, QTs.ksu-1AS.1 and QTs.ksu-7AS were significantly associated with tan spot resistance and contributed by TA4161-L1. QTs.ksu-7AS is a novel QTL and explained 17% of the phenotypic variation. Novel QTLs for APR to LR and tan spot identified in SHWs add new variation for broadening the gene pool of wheat and providing resources for breeding of durable resistant cultivars.
Libri sul tema "Seedling resistance"
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Lantz, Clark W. Benomyl improves storability and brown spot resistance of longleaf pine seedlings. Atlanta, GA: Southern Region, USDA Forest Service, 1988.
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James, Robert L. Resistance of Botrytis cinerea to vinclozolin, iprodione and dicloran. Missoula, Mont: USDA Forest Service, Northern Region, Cooperative Forestry and Pest Management, 1985.
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Krasowski, Marek J. Winter freezing injury and frost acclimation in planted coniferous seedlings: A literature review and case study from northeastern British Columbia. Victoria, B.C: Forestry Canada, 1993.
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Thomas, Barbara Ruth. Guidelines for seed transfer of western white pine in B.C. based on frost hardiness. [Victoria, B.C.]: Forestry Canada, 1993.
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Hawkins, Christopher David Borden. SIVE, a new stock quality test: The first approximation. Victoria, B.C: Forestry Canada, 1992.
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Cowger, Christina. Cephalosporium stripe of wheat: Seedling-based resistance screening and pathogenic variability. 1997.
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Conditions Inducing Heat Resistance in Seedling Plants of Corn, Wheat, and Sorghum. Hassell Street Press, 2021.
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Melton, Lisa L. Soil surface effects on soil water, soil temperature, and Douglas-fir seedling injury following radiation frost damage events. 1989.
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Schuch, Ursula K. Frost hardiness of Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) seedlings raised in three nurseries. 1987.
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Zwiazek, Janusz J. Chilling and humidity effects on the development, frost and drought resistance of containerized white spruce seedlings: Final report 1998. Alberta Environmental Protection, 1998.
Cerca il testo completoCapitoli di libri sul tema "Seedling resistance"
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Wright, L. Neal. "Drought Influence on Germination and Seedling Emergence". In Drought Injury and Resistance in Crops, 19–44. Madison, WI, USA: Crop Science Society of America, 2015. http://dx.doi.org/10.2135/cssaspecpub2.c2.
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Nazari, K., M. Torabi, A. Saidi e R. Johnson. "Seedling and Adult-Plant Resistance to Yellow Rust". In Wheat in a Global Environment, 397–403. Dordrecht: Springer Netherlands, 2001. http://dx.doi.org/10.1007/978-94-017-3674-9_51.
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Saif, Abdulwahid, Aref Al-Shamiri e Abdulnour Shaher. "Development of new bread wheat resistant mutants for Ug99 rust disease (Puccinia graminis f. sp. tritici)." In Mutation breeding, genetic diversity and crop adaptation to climate change, 312–19. Wallingford: CABI, 2021. http://dx.doi.org/10.1079/9781789249095.0032.
Testo completoAbstract (sommario):
Abstract M3 derived mutants from two bread wheat varieties, namely, 'Giza 186' and 'Saha 93', were screened for resistance to the rust Ug99 at two locations in Njoro (Kenya) and in Tihama (Yemen). At Tihama, two mutants of 'Giza 186' (G-M2-2010-1-28 and G-M2-2010-41-52) and four mutants of 'Saha 93' (S-M2-2010-16-12, S-M2-2010-21-13, S-M2-2010-22-14 and S-M2-2010-27-15) were seen to be resistant at both seedling and adult stages while their parents were resistant at seedling stage and susceptible at adult stage. In Kenya, the resistance score of the mutants was slightly different from those obtained at Tihama. The mutants G-M2-2010-1-28 and G-M2-2010-41-52 were stable in their level of resistance recorded at Tihama, but only two mutants of 'Saha 93' (S-M2-2010-16-12 and S-M2-2010-27-15) were resistant at both growth stages. S-M2-2010-22-14 and S-M2-2010-21-13 were resistant at the seedling stage while susceptible at adult stage. Further selection on these mutants for yield potential, agronomic performance and yellow rust disease resistance, as well as on selected mutants of both 'Giza 186' and 'Saha 93', at M5-M6 stages identified superior mutant lines compared with the two parents 'Saha 93' and 'Giza 186'. These included the line Erra-010-GM2w-41-52-40, which ranked first in yield (3768 kg/ha), followed by the lines Erra-010-SwM2-16-12-19, Erra-010-GM2w-1-28-18 and Erra-010-SwM2-22-14-6. Moreover, it can be concluded that Erra-010-GM2w-41-52-40 and Erra-010-SwM2-16-12-19 are highly recommended for their resistance to stem and yellow rust diseases as well as for yield potential and preference by farmers. Therefore, efforts are in progress to increase their seeds for dissemination over a wide range of farmers and wheat areas where rust diseases are an epidemic, and for registration of the lines as improved mutant varieties.
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Abu Hassan, Affrida, Norazlina Noordin, Zaiton Ahmad, Mustapha Akil, Faiz Ahmad e Rusli Ibrahim. "Protocol for Mass Propagation of Plants Using a Low-Cost Bioreactor". In Efficient Screening Techniques to Identify Mutants with TR4 Resistance in Banana, 177–87. Berlin, Heidelberg: Springer Berlin Heidelberg, 2022. http://dx.doi.org/10.1007/978-3-662-64915-2_11.
Testo completoAbstract (sommario):
AbstractConventional in vitro mass propagation methods are labour-intensive, costly and have a low degree of automation. Bioreactor or automated growth vessel systems using liquid media were developed to overcome these problems. The use of liquid instead of solid culture medium for plant micropropagation offers better access to medium components and scalability through automation. However, the cost of setting up a bioreactor system is one of its disadvantages as such systems are expensive with limited number of manufacturers. A low-cost bioreactor system was set up using recycled, low biodegradable plastic bottles. This low-cost bioreactor, based on temporary immersion principle, has proven to be effective as a vessel for rapid plant propagation. It is designed to reduce the production cost of plant micropropagation. This chapter explains the step-by-step methods for setting up a low-cost bioreactor for banana seedling production. This low-cost bioreactor system has the potential to be adapted for large scale in vitro cultivation of the plant seedlings.
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Bakshi, Suman, Johar Singh e Sanjay J. Jambhulkar. "Isolation and characterization of yellow rust resistant mutants in wheat." In Mutation breeding, genetic diversity and crop adaptation to climate change, 103–10. Wallingford: CABI, 2021. http://dx.doi.org/10.1079/9781789249095.0010.
Testo completoAbstract (sommario):
Abstract Stripe rust, also known as yellow rust, caused by Puccinia striiformis f. sp. tritici (Pst), is a major threat to wheat production leading to yield losses up to 84%. Due to climate change, new races of the yellow rust pathogen are appearing for which no durable source of resistance has been observed in the present high-yielding varieties. A mutation breeding programme was initiated in two popular varieties, namely PBW343 and HD2967, using gamma-ray and electron beam irradiation. Gamma-ray doses of 250, 300 and 350 Gy and electron beam doses of 150, 200 and 250 Gy were used for seed irradiation. The M2 population was screened in the field from seedling to adult plant stage by spraying a mixture of urediniospores of Pst pathotypes. Disease severity was recorded as the percentage of leaf area covered by the rust pathogen following a modified Cobb's scale. A total of 52 putative yellow rust resistant mutants in HD2967 and 63 in PBW343 were isolated. The number of mutants was higher in the electron beam irradiated population compared with gamma-rays. The absence of sporulation and spore production of the rust pathogen on the mutants indicated resistance. Mutant plants showing seedling resistance also showed resistance at adult plant stage. Seed yield and its contributing characters were better in the mutants compared with the parents. These rust resistant mutants could be novel sources of stripe rust or yellow rust resistance. The plant-to-row progenies of these mutants were confirmed and characterized in the M3 generation.
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Torabi, M., e K. Nazari. "Seedling and adult plant resistance to yellow rust in Iranian bread wheats". In Developments in Plant Breeding, 109–12. Dordrecht: Springer Netherlands, 1997. http://dx.doi.org/10.1007/978-94-011-4896-2_15.
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Shimizu, Hiroshi, e Royal D. Heins. "Estimating Cuticle Resistance of Seedling Shoot Tips Based on the Penman-Monteith Model". In Transplant Production in the 21st Century, 59–62. Dordrecht: Springer Netherlands, 2000. http://dx.doi.org/10.1007/978-94-015-9371-7_8.
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Xiang, Chunyang, Jin Du, Peipei Zhang, Gaoyi Cao e Dan Wang. "Preliminary Study on Salt Resistance Seedling Trait in Maize by SRAP Molecular Markers". In Lecture Notes in Electrical Engineering, 11–18. Berlin, Heidelberg: Springer Berlin Heidelberg, 2015. http://dx.doi.org/10.1007/978-3-662-45657-6_2.
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Lantican, Gaudencia A. "Field Screening of Gamma-Irradiated Cavendish Bananas". In Efficient Screening Techniques to Identify Mutants with TR4 Resistance in Banana, 97–109. Berlin, Heidelberg: Springer Berlin Heidelberg, 2022. http://dx.doi.org/10.1007/978-3-662-64915-2_7.
Testo completoAbstract (sommario):
AbstractIn our search for Cavendish bananas to withstand Fusarium oxysporum f. sp. cubense (Foc TR4) and other diseases, field screening of tissue-cultured Grand Nain banana seedlings derived from gamma-irradiated shoot tips was explored. Six months after irradiation and multiplication in the laboratory, the plantlets (M1V6) were individually grown in seedling bags under screen house conditions for 8 weeks, side-by-side with non-irradiated plantlets of the same clone. Once acclimatized, the banana plants were grown in an area confirmed positive of Foc TR4 (based on previous farm records stating that more than 50% of the plant population succumbed to the disease). Seedlings from each treatment (dose of radiation) were divided into four replicates, regardless of the number of plants. Each plant was given a unique identification code for traceability during disease monitoring, bunch and fruit quality evaluation.Incidences of Foc TR4, Moko disease (Ralstonia solanacearum) and virus diseases were monitored weekly. Plants found positive of any disease were eradicated immediately. The plant population for the succeeding generation was managed by removing the unwanted suckers, 12 weeks from planting using a spade gouge and keeping only one sucker per plant for the next generation. Agronomic characters of each plant were taken at the flowering stage. These included age to flower, height, pseudostem circumference, number of leaves and height of the sucker. The bunch was harvested 12 weeks from flowering. The number of hands in a bunch, the number of fingers and weight of a hand were recorded. The same agronomic characters of the plant were taken for the succeeding generations.Plants left standing in the field without any disease symptoms 3 years after planting were considered as putative mutants and were selected as candidate lines for multiplication and second-generation field screening. Only healthy suckers (free from viruses) were further multiplied via tissue culture technique to reach M1V6. Clean suckers from each line free of soil debris or dirt were sent to the laboratory for multiplication. At least 1000 plantlets were produced from each line for the second-generation field screening. These were grown in two locations – with and without records of Foc TR4. Field monitoring activities including plant population management, disease incidence assessment and fruit quality evaluation were carried out following the same protocols used in the establishment of the first-generation plants. Lines with population showing ≤10% Foc TR4 after the first harvest, with good vigor, fruit quality and productivity were considered as candidates for further multiplication, farmers distribution and field planting under semi-commercial scale.
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Gomez-Pando, Luz, Jesus Bernardo-Rojas, Denisse Deza-Montoya, Martha Ibañez-Tremolada e Enrique Aguilar-Castellanos. "Mutation induction to improve quinoa (Chenopodium quinoa) resistance to downy mildew (Peronospora variabilis)." In Mutation breeding, genetic diversity and crop adaptation to climate change, 194–202. Wallingford: CABI, 2021. http://dx.doi.org/10.1079/9781789249095.0019.
Testo completoAbstract (sommario):
Abstract Quinoa is an important crop due to its nutritional characteristics (better than cereals) and its tolerance to abiotic stresses. However, various factors such as high susceptibility to diseases, especially downy mildew caused by Peronospora variabilis, limit its agricultural performance. Genetic improvement of quinoa could reduce the need to use fungicides for this crop and maintain the organic quality of Peruvian production in small-scale farms. Seeds of var. 'Amarilla Marangani', irradiated with 150 and 250 Gy of gamma-rays (60Co), were evaluated in two experimental locations in Peru: coastland at La Molina and highland at Huancayo. Resistance to downy mildew and other agricultural traits in the M3 and M4 generations was studied. In both locations, downy mildew was observed in susceptible plants under natural infection, from the seedling stage to plant maturity. At the coastland site, six mutants with 30% leaf infection were obtained in the progeny of plants exposed to 150 Gy. Five additional mutants with 40% leaf infection were found in the progeny of plants exposed to 250 Gy. In the highland trial, only seven lines were identified with 30% severity (foliar area with symptoms) among the plants from the 150 Gy experiment. The parent materials showed 70-80% disease severity. Mutant lines with quantitative resistance and tolerance to downy mildew, high yield potential, reduced duration, shorter plant height, altered inflorescence shape and grain colour mutations were selected from both doses. This study showed that quantitative resistance and tolerance to downy mildew could be obtained in quinoa and this resulted in increased grain yields.
Atti di convegni sul tema "Seedling resistance"
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Huang, Lin-kai, Xin-quan Zhang, Wen-gang Xie, Wan-ping Zhou e Liang Chen. "Evaluation of drought resistance for Hemarthria compressa at seedling stage". In International Conference on Photonics and Image in Agricultural Engineering (PIAGENG 2010), a cura di Honghua Tan. SPIE, 2011. http://dx.doi.org/10.1117/12.886382.
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Jiang, Yu'Ting, Ya Luo, Fan Mo, Ya'Jie Ling, Qin Mo, Shu Luo e Hao'Ru Tang. "Effect of Astaxanthin on the Growth and Resistance of Strawberry Seedling under Cadmium Stress". In 2017 3rd International Forum on Energy, Environment Science and Materials (IFEESM 2017). Paris, France: Atlantis Press, 2018. http://dx.doi.org/10.2991/ifeesm-17.2018.381.
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Zhong, Yue, Ya Luo, Cong Ge, Qin Mo, Ya'Jie Lin, Shu Luo e Hao'Ru Tang. "Effect of Astaxanthin on the Growth and Resistance of Strawberry Seedling under Salt Stress". In 2017 3rd International Forum on Energy, Environment Science and Materials (IFEESM 2017). Paris, France: Atlantis Press, 2018. http://dx.doi.org/10.2991/ifeesm-17.2018.385.
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Zhigacheva, I. V. "THE SPATIAL HINDERED PHENOLS INCREASE THE STABILITY OF PEA SEEDLING TO STRESS IMPACTS". In The All-Russian Scientific Conference with International Participation and Schools of Young Scientists "Mechanisms of resistance of plants and microorganisms to unfavorable environmental". SIPPB SB RAS, 2018. http://dx.doi.org/10.31255/978-5-94797-319-8-1236-1240.
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McGrath, J. Mitchell, e Suba Nagendran. "Discovery of resistance to seedling disease caused by Rhizoctonia solani AG2-2, description of the host-pathogen interaction, and development of a seedling disease screening nursery". In American Society of Sugar Beet Technologist. ASSBT, 2007. http://dx.doi.org/10.5274/assbt.2007.55.
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Alen’kina, S. A., K. A. Roshchupkina e V. E. Nikitina. "EFFECT OF AZOSPIRILLUM LECTINS ON PROLINE CONTENT IN WHEAT SEEDLING ROOTS EXPOSED TO HEAVY METALS". In The All-Russian Scientific Conference with International Participation and Schools of Young Scientists "Mechanisms of resistance of plants and microorganisms to unfavorable environmental". SIPPB SB RAS, 2018. http://dx.doi.org/10.31255/978-5-94797-319-8-64-67.
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AL-Rukabi, M. N., e V. I. Leunov. "Evaluation of tomato hybrids with different level of ripe rate under hydroponic conditions (fitopyramide)". In Растениеводство и луговодство. Тимирязевская сельскохозяйственная академия, 2020. http://dx.doi.org/10.26897/978-5-9675-1762-4-2020-49.
Testo completoAbstract (sommario):
Greenhouse tomatoes are divided into early, medium and late-maturing. The days from seedling germination to the first harvest are taken into account. Tomato has a huge potential for heterosis in terms of precocity, overall yield, signs of resistance and uniformity. The preferred agricultural method is hydroponics, which allows you to grow plants without using soil, only using mineral nutrient solutions in water. The cultivation of tomato plants on the " Fitopyramida " will allow to sell their products in the periods with the highest realized prices. An experiment on variety testing of 11 tomato hybrids of different product groups that differ in precocity allowed us to select the most adapted to the conditions of the " Fitopyramida " technology, including the indeterminate beef Ruddy ball F1, cherry hybrids Elf F1 and orange-fruited cherry Magic harp F1. the determinant hybrid Captain F1 showed Good results.
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Butsanets, P. A., A. S. Baik, I. P. Generozova e A. G. Shugaev. "Salicylic acid increases resistance to thermal stress of lupine seedlings". In IX Congress of society physiologists of plants of Russia "Plant physiology is the basis for creating plants of the future". Kazan University Press, 2019. http://dx.doi.org/10.26907/978-5-00130-204-9-2019-90.
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Generozova, I. P., P. A. Butsanets e A. G. Shugaev. "OXIDATIVE STRESS AT PEAS SEEDLINGS DURING RESTORATION AFTER ADVERSE FACTORS". In The All-Russian Scientific Conference with International Participation and Schools of Young Scientists "Mechanisms of resistance of plants and microorganisms to unfavorable environmental". SIPPB SB RAS, 2018. http://dx.doi.org/10.31255/978-5-94797-319-8-221-225.
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Kuznetsova, V. A. "The joint use of strains of microorganisms and natural growth regulators to increase soy resistance to diseases". In 2nd International Scientific Conference "Plants and Microbes: the Future of Biotechnology". PLAMIC2020 Organizing committee, 2020. http://dx.doi.org/10.28983/plamic2020.148.
Testo completoAbstract (sommario):
Growth regulators EcoLarix and ExtraCor together with a biofungicide based on the strain of the fungus Trichoderma viride contributed to the improvement of growth indicators of soybean seedlings healed them from a complex of root rot of various etiologies.
Rapporti di organizzazioni sul tema "Seedling resistance"
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Sela, Hanan, Eduard Akhunov e Brian J. Steffenson. Population genomics, linkage disequilibrium and association mapping of stripe rust resistance genes in wild emmer wheat, Triticum turgidum ssp. dicoccoides. United States Department of Agriculture, gennaio 2014. http://dx.doi.org/10.32747/2014.7598170.bard.
Testo completoAbstract (sommario):
The primary goals of this project were: (1) development of a genetically characterized association panel of wild emmer for high resolution analysis of the genetic basis of complex traits; (2) characterization and mapping of genes and QTL for seedling and adult plant resistance to stripe rust in wild emmer populations; (3) characterization of LD patterns along wild emmer chromosomes; (4) elucidation of the multi-locus genetic structure of wild emmer populations and its correlation with geo-climatic variables at the collection sites. Introduction In recent years, Stripe (yellow) rust (Yr) caused by Pucciniastriiformis f. sp. tritici(PST) has become a major threat to wheat crops in many parts of the world. New races have overcome most of the known resistances. It is essential, therefore, that the search for new genes will continue, followed by their mapping by molecular markers and introgression into the elite varieties by marker-assisted selection (MAS). The reservoir of genes for disease and pest resistance in wild emmer wheat (Triticumdicoccoides) is an important resource that must be made available to wheat breeders. The majority of resistance genes that were introgressed so far in cultivated wheat are resistance (R) genes. These genes, though confering near-immunity from the seedling stage, are often overcome by the pathogen in a short period after being deployed over vast production areas. On the other hand, adult-plant resistance (APR) is usually more durable since it is, in many cases, polygenic and confers partial resistance that may put less selective pressure on the pathogen. In this project, we have screened a collection of 480 wild emmer accessions originating from Israel for APR and seedling resistance to PST. Seedling resistance was tested against one Israeli and 3 North American PST isolates. APR was tested on accessions that did not have seedling resistance. The APR screen was conducted in two fields in Israel and in one field in the USA over 3 years for a total of 11 replicates. We have found about 20 accessions that have moderate stripe rust APR with infection type (IT<5), and about 20 additional accessions that have novel seedling resistance (IT<3). We have genotyped the collection using genotyping by sequencing (GBS) and the 90K SNP chip array. GBS yielded a total 341K SNP that were filtered to 150K informative SNP. The 90K assay resulted in 11K informative SNP. We have conducted a genome-wide association scan (GWAS) and found one significant locus on 6BL ( -log p >5). Two novel loci were found for seedling resistance. Further investigation of the 6BL locus and the effect of Yr36 showed that the 6BL locus and the Yr36 have additive effect and that the presence of favorable alleles of both loci results in reduction of 2 grades in the IT score. To identify alleles conferring adaption to extreme climatic conditions, we have associated the patterns of genomic variation in wild emmer with historic climate data from the accessions’ collection sites. The analysis of population stratification revealed four genetically distinct groups of wild emmer accessions coinciding with their geographic distribution. Partitioning of genomic variance showed that geographic location and climate together explain 43% of SNPs among emmer accessions with 19% of SNPs affected by climatic factors. The top three bioclimatic factors driving SNP distribution were temperature seasonality, precipitation seasonality, and isothermality. Association mapping approaches revealed 57 SNPs associated with these bio-climatic variables. Out of 21 unique genomic regions controlling heading date variation, 10 (~50%) overlapped with SNPs showing significant association with at least one of the three bioclimatic variables. This result suggests that a substantial part of the genomic variation associated with local adaptation in wild emmer is driven by selection acting on loci regulating flowering. Conclusions: Wild emmer can serve as a good source for novel APR and seedling R genes for stripe rust resistance. APR for stripe rust is a complex trait conferred by several loci that may have an additive effect. GWAS is feasible in the wild emmer population, however, its detection power is limited. A panel of wild emmer tagged with more than 150K SNP is available for further GWAS of important traits. The insights gained by the bioclimatic-gentic associations should be taken into consideration when planning conservation strategies.
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Flaishman, Moshe, Herb Aldwinckle, Shulamit Manulis e Mickael Malnoy. Efficient screening of antibacterial genes by juvenile phase free technology for developing resistance to fire blight in pear and apple trees. United States Department of Agriculture, dicembre 2008. http://dx.doi.org/10.32747/2008.7613881.bard.
Testo completoAbstract (sommario):
Objectives: The original objectives of this project were to: Produce juvenile-free pear and apple plants and examine their sensitivity to E. amylovora; Design novel vectors, for antibacterial proteins and promoters expression, combined with the antisense TFL1 gene, and transformation of Spadona pear in Israel and Galaxy apple in USA. The original objectives were revised from the development of novel vectors with antibacterial proteins combined with the TFL-1 due to the inefficiency of alternative markes initially evaluated in pear, phoshomannose-isomerase and 2-deoxyglucose-6-phosphate phosphatase and the lack of development of double selection system. The objectives of project were revised to focus primarily on the development additional juvenile free systems by the use of another pear variety and manipulation of the FT gene under the control of several promoters. Based on the results creation of fire blight resistance pear variety was developed by the use of the juvenile free transgenic plant. Background: Young tree seedlings are unable to initiate reproductive organs and require a long period of shoot maturation, known as juvenile phase. In pear, juvenile period can last 5-7 years and it causes a major delay in breeding programs. We isolated the TFL1 gene from Spadona pear (PcTFL1-1) and produced transgenic ‘Spadona’ trees silencing the PcTFL1 gene using a RNAi approach. Transgenic tissue culture ‘Spadona’ pear flowered in vitro. As expected, the expression of the endogenous PcTFL1 was suppressed in the transgenic line that showed precocious flowering. Transgenic plants were successfully rooted in the greenhouse and most of the plants flowered after only 4-8 months, whereas the non-transformed control plants have flowered only after 5-6 years of development. Major achievements: Prior to flower induction, transgenic TFL1-RNAi ‘Spadona’ plants developed a few branches and leaves. Flower production in the small trees suppressed the development of the vegetative branches, thus resulting in compact flowering trees. Flowering was initiated in terminal buds, as described for the Arabidopsis tfl1 mutant. Propagation of the transgenic TFL1-RNAi ‘Spadona’ was performed by bud grafting on 'Betulifolia' rootstock and resulted in compact flowering trees. The transgenic flowering grafted plants were grown in the greenhouse under a long photoperiod for one year, and flowered continuously. Pollination of the transgenic flowers with ‘Costia‘ pear pollen generated fruits of regular shape with fertile F1 seeds. The F1 transgenic seedling grown in the greenhouse formed shoots and produced terminal flowers only five months after germination. In addition, grafted F1 transgenic buds flower and fruit continuously, generating hybrid fruits with regular shape, color and taste. Several pear varieties were pollinated with the transgenic TFL1-RNAi ‘Spadona’ pollen including `Herald Harw` that was reported to have resistance to fire blight diseases. The F-1 hybrid seedlings currently grow in our greenhouse. We conclude that the juvenile-free transgenic ‘Spadona’ pear enables the development of a fast breeding method in pear that will enable us to generate a resistance pear to fire blight. Implications: The research supported by this grant has demonstrated the use of transgenic juvenile free technology in pear. The use of the juvenile free technology for enhancement of conventional breeding in fruit tree will serve to enhance fast breeding systems in pear and another fruit trees.
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Dubcovsky, Jorge, Tzion Fahima e Ann Blechl. Molecular characterization and deployment of the high-temperature adult plant stripe rust resistance gene Yr36 from wheat. United States Department of Agriculture, novembre 2013. http://dx.doi.org/10.32747/2013.7699860.bard.
Testo completoAbstract (sommario):
Stripe rust, caused by Puccinia striiformis f. sp. tritici is one of the most destructive fungal diseases of wheat. Virulent races that appeared within the last decade caused drastic cuts in yields. The incorporation of genetic resistance against this pathogen is the most cost-effective and environmentally friendly solution to this problem. However, race specific seedling resistance genes provide only a temporary solution because fungal populations rapidly evolve to overcome this type of resistance. In contrast, high temperature adult plant (HTAP) resistance genes provide a broad spectrum resistance that is partial and more durable. The cloning of the first wheat HTAP stripe rust resistance gene Yr36 (Science 2009, 323:1357), funded by our previous (2007-2010) BARD grant, provided us for the first time with an entry point for understanding the mechanism of broad spectrum resistance. Two paralogous copies of this gene are tightly linked at the Yr36 locus (WKS1 and WKS2). The main objectives of the current study were to characterize the Yr36 (WKS) resistance mechanism and to identify and characterize alternative WKSgenes in wheat and wild relatives. We report here that the protein coded by Yr36, designated WKS1, that has a novel architecture with a functional kinase and a lipid binding START domain, is localized to chloroplast. Our results suggest that the presence of the START domain may affect the kinase activity. We have found that the WKS1 was over-expressed on leaf necrosis in wheat transgenic plants. When the isolated WKS1.1 splice variant transcript was transformed into susceptible wheat it conferred resistance to stripe rust, but the truncated variant WKS1.2 did not confer resistance. WKS1.1 and WKS1.2 showed different lipid binding profiling. WKS1.1 enters the chloroplast membrane, while WKS1.2 is only attached outside of the chloroplast membrane. The ascorbate peroxidase (APX) activity of the recombinant protein of TmtAPXwas found to be reduced by WKS1.1 protein in vitro. The WKS1.1 mature protein in the chloroplast is able to phosphorylate TmtAPXprotein in vivo. WKS1.1 induced cell death by suppressing APX activity and reducing the ability of the cell to detoxify reactive oxygen. The decrease of APX activity reduces the ability of the plant to detoxify the reactive H2O2 and is the possible mechanism underlying the accelerated cell death observed in the transgenic plants overexpressing WKS1.1 and in the regions surrounding a stripe rust infection in the wheat plants carrying the natural WKS1.1 gene. WKS2 is a nonfunctional paralog of WKS1 in wild emmer wheat, probably due to a retrotransposon insertion close to the alternative splicing site. In some other wild relatives of wheat, such as Aegilops comosa, there is only one copy of this gene, highly similar to WKS2, which is lucking the retrotransposon insertion. WKS2 gene present in wheat and WKS2-Ae from A. showed a different pattern of alternative splice variants, regardless of the presence of the retrotransposon insertion. Susceptible Bobwhite transformed with WKS2-Ae (without retrotansposon insertion in intron10), which derived from Aegilops comosaconferred resistance to stripe rust in wheat. The expression of WKS2-Ae in transgenic plants is up-regulated by temperature and pathogen infection. Combination of WKS1 and WKS2-Ae shows improved stripe rust resistance in WKS1×WKS2-Ae F1 hybrid plants. The obtained results show that WKS1 protein is accelerating programmed cell death observed in the regions surrounding a stripe rust infection in the wheat plants carrying the natural or transgenic WKS1 gene. Furthermore, characterization of the epistatic interactions of Yr36 and Yr18 demonstrated that these two genes have additive effects and can therefore be combined to increase partial resistance to this devastating pathogen of wheat. These achievements may have a broad impact on wheat breeding efforts attempting to protect wheat yields against one of the most devastating wheat pathogen.
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Davis, Eric L., Yuji Oka, Amit Gal-On, Todd Wehner e Aaron Zelcer. Broad-spectrum Resistance to Root-Knot Nematodes in Transgenic Cucurbits. United States Department of Agriculture, giugno 2013. http://dx.doi.org/10.32747/2013.7593389.bard.
Testo completoAbstract (sommario):
Root-knot nematodes (RKN), Meloidogyne spp., are extremely destructive pathogens of cucurbit crops grown in the United States and Israel. The safety and environmental concerns of toxic nematicides, and limited sources of natural cucurbit resistance to the four major species of Meloidogyne that threaten these crops in Israel and the U.S., have emphasized the use of biotechnology to develop cucurbits with novel RKN resistance. The U.S. scientists have identified over 40 unique RKN parasitism genes that encode nematode secretions involved in successful plant root infection by RKN, and they have demonstrated that expression of a double-stranded RNA (dsRNA) complementary to a RKN parasitism gene (called 16DIO) in Arabidopsis thaliana induced RNA interference (RNAi)-mediated silencing of the RKN16DlO gene and produced transgenic plants with strong resistance to all four major RKN species. The expression 8D05 parasitism gene was found to coincide with the timing of upregulation of NtCel7 promoter (identified to be upregulated in giantcells by US scientists). NtCel7 promoter was used to express the genes at the right time (early stages of infection) and in the right place (giant-cells) in transgenic plants. US partners produced NtCel7 (nematode-induced promoter)-driven 16DlO-RNAi and 8DOS-RNAi constructs, pHANNIBAL 4D03-RNAi construct and modified 16DlO-RNAi construct (for increased RNAi expression and efficacy) for cucurbit transformation in Israel. In Arabidopsis, some 16DlO-RNAi plant lines show greater levels of resistance to M. incognita than others, and within these lines resistance of greater than 90% reduction in infection is observed among almost all replicates in US. The level of observed nematode resistance is likely to be directly correlated with the level of RNAi expression in individual plants. In Israel, all the RKN parasitism genes-RNAi constructs were successfully transformed into cucumber and melon. The transgenic lines were evaluated for expression of the transgene siRNA in leaves and roots. Those displaying transgene siRNA accumulation were passed on for nematode resistance analysis. Rl seedlings from different lines were subjected to evaluation for resistance to M. javanica. None of the lines was resistant to the nematode in contrast with US partner's results in Arabidopsis. This could be for the following reasons: a) The level of transgene siRNA was insufficient in cucumber and tomato to cause resislance. b) 111e nemalode species on cucwnber IIlay be different ur act in a different manner. c) The assay was performed in soil with a high level of nematode inoculation, and not in petri dish, which may not permit the observation of a low level of resistance.
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Freeman, Stanley, e Russell J. Rodriguez. The Interaction Between Nonpathogenic Mutants of Colletotrichum and Fusarium, and the Plant Host Defense System. United States Department of Agriculture, settembre 2000. http://dx.doi.org/10.32747/2000.7573069.bard.
Testo completoAbstract (sommario):
The intent of this proposal was to study the interaction between nonpathogenic mutants of Colletotrichum magna and Fusarium oxysporum, and the cucurbit host defense system. We had shown previously that a nonpathogenic endophytic mutant path- 1 of C. magna, caused no visible disease symptoms but protected watermelon seedlings from disease caused by the wildtype isolate and F. o. niveum. Objectives were: 1) Determine the microscopic, biochemical and molecular genetic interaction between "protected" (path- 1 colonized) cucurbit hosts and wildtype isolates of C. magna; 2) Isolate non-pathogenic mutants of F.o. melonis and test feasibility for protecting plants against fungal diseases. We found that path-1 caused no visible disease symptoms in cucurbit seedlings but conferred disease resistance against pathogenic isolates of C. magna, C. orbiculare, and F. oxysporum. Disease resistance conferred by path-1 correlated to a decrease in the time of activation of host defense systems after exposure of path-1 colonized plants to virulent pathogens. This was determined by monitoring the biochemical activity of PAL and peroxidase, and the deposition of lignin. It appears that path-1-conferred disease resistance is a multigenic phenomenon which should be more difficult for pathogen to overcome than single gene conferred resistance. Based on the benefits conferred by path-1, we have defined this mutant as expressing a mutualistic lifestyle. REMI (restriction enzyme-mediated integration) nonpathogenic mutants were also isolated using pHA1.3 plasmid linearized with Hind III and transformed into wildtype C. magna. The integrated vector and flanking genomic DNA sequences in REMI mutant R1 was re-isolated and cloned resulting in a product of approximately 11 kb designated pGMR1. Transformations of wildtype C. magna with pGMR1 resulted in the same non-pathogenic phenotype. A nonpathogenic mutant of F.o. melonis (pathogenic to melon) was isolated that colonized melon plants but elicited no disease symptoms in seedlings and conferred 25 - 50% disease protection against the virulent wildtype isolate. Subsequently, nonpathogenic mutant isolates of F.o. niveum (pathogenic to watermelon) were also isolated. Their protection capacity against the respective wildtype parent is currently under investigation. This research has provided information toward a better understanding of host-parasite interactions; specifically, endophytes, pathogens and their hosts. It will also allow us to assess the potential for utilizing nonpathogenic mutants as biological control agents against fungal pathogens and isolating molecular genetic factors of pathogenicity in Fusarium.
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Seginer, Ido, Daniel H. Willits, Michael Raviv e Mary M. Peet. Transpirational Cooling of Greenhouse Crops. United States Department of Agriculture, marzo 2000. http://dx.doi.org/10.32747/2000.7573072.bard.
Testo completoAbstract (sommario):
Background Transplanting vegetable seedlings to final spacing in the greenhouse is common practice. At the time of transplanting, the transpiring leaf area is a small fraction of the ground area and its cooling effect is rather limited. A preliminary modeling study suggested that if water supply from root to canopy is not limiting, a sparse crop could maintain about the same canopy temperature as a mature crop, at the expense of a considerably higher transpiration flux per leaf (and root) area. The objectives of this project were (1) to test the predictions of the model, (2) to select suitable cooling methods, and (3) to compare the drought resistance of differently prepared seedlings. Procedure Plants were grown in several configurations in high heat load environments, which were moderated by various environmental control methods. The difference between the three experimental locations was mainly in terms of scale, age of plants, and environmental control. Young potted plants were tested for a few days in small growth chambers at Technion and Newe Ya'ar. At NCSU, tomato plants of different ages and planting densities were compared over a whole growing season under conditions similar to commercial greenhouses. Results Effect of spacing: Densely spaced plants transpired less per plant and more per unit ground area than sparsely spaced plants. The canopy temperature of the densely spaced plants was lower. Air temperature was lower and humidity higher in the compartments with the densely spaced plants. The difference between species is mainly in the canopy-to-air Bowen ratio, which is positive for pepper and negative for tomato. Effect of cooling methods: Ventilation and evaporative pad cooling were found to be effective and synergitic. Air mixing turned out to be very ineffective, indicating that the canopy-to-air transfer coefficient is not the limiting factor in the ventilation process. Shading and misting, both affecting the leaf temperature directly, proved to be very effective canopy cooling methods. However, in view of their side effects, they should only be considered as emergency measures. On-line measures of stress: Chlorophyll fluorescence was shown to accurately predict photosynthesis. This is potentially useful as a rapid, non-contact way of assessing canopy heat stress. Normalized canopy temperature and transpiration rate were shown to correlate with water stress. Drought resistance of seedlings: Comparison between normal seedlings and partially defoliated ones, all subjected to prolonged drought, indicated that removing about half of the lowermost leaves prior to transplanting, may facilitate adjustment to the more stressful conditions in the greenhouse. Implications The results of this experimental study may lead to: (1) An improved model for a sparse canopy in a greenhouse. (2) A better ventilation design procedure utilizing improved estimates of the evaporation coefficient for different species and plant configurations. (3) A test for the stress resistance of transplants.
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Reisch, Bruce, Pinhas Spiegel-Roy, Norman Weeden, Gozal Ben-Hayyim e Jacques Beckmann. Genetic Analysis in vitis Using Molecular Markers. United States Department of Agriculture, aprile 1995. http://dx.doi.org/10.32747/1995.7613014.bard.
Testo completoAbstract (sommario):
Genetic analysis and mapping in grapes has been difficult because of the long generation period and paucity of genetic markers. In the present work, chromosome linkage maps were developed with RAPD, RFLP and isozyme loci in interspecific hybrid cultivars, and RAPD markers were produced in a V. vinifera population. In three cultivars, there were 19 linkage groups as expected for a species with 38 somatic chromosomes. These maps were used to locate chromosome regions with linkages to important genes, including those influencing powdery mildew and botrytis bunch rot resistance; flower sex; and berry shape. In V. vinifera, the occurrence of specific markers was correlated with seedlessness, muscat flavor and fruit color. Polymorphic RAPD bands included single copy as well as repetitive DNA. Mapping procedures were improved by optimizing PCR parameters with grape DNA; by the development of an efficient DNA extraction protocol; and with the use of long (17- to 24-mer) primers which amplify more polymorphic loci per primer. DNA fingerprint analysis with RAPD markers indicated that vinifera cultivars could be separated readily with RAPD profiles. Pinot gris, thought to be a sort of Pinot noir, differed by 12 bands from Pinot noir. This suggests that while Pinot gris may be related to Pinot noir, it is not likely to be a clone. The techniques developed in this project are now being further refined to use marker-assisted selection in breeding programs for the early selection of elite seedlings. Furthermore, the stage has been set for future attempts to clone genes from grapes based upon map locations.
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Yalovsky, Shaul, e Julian Schroeder. The function of protein farnesylation in early events of ABA signal transduction in stomatal guard cells of Arabidopsis. United States Department of Agriculture, gennaio 2002. http://dx.doi.org/10.32747/2002.7695873.bard.
Testo completoAbstract (sommario):
Loss of function mutations in the farnesyltransferase β subunit gene ERA1 (enhanced response to abscisic acid), cause abscisic acid hypersensitivity in seedlings and in guard cells. This results in slowed water loss of plants in response to drought. Farnesyltransferase (PFT) catalyses the attachment of the 15-carbon isoprenoid farnesyl to conserved cysteine residues located in a conserved C-terminal domain designated CaaX box. PFT is a heterodimeric protein comprised of an a and b sununits. The a subunit is shared between PFT and geranylgeranyltransferase-I (PGGTI) which catalyses the attachemt of the 20-carbon isoprenoid geranylgeranyl to CaaX box proteins in which the last amino acid is almost always leucine and in addition have a polybasic domain proximal to the CaaL box. Preliminary data presented in the proposal showed that increased cytoplasmic Ca2+ concentration in stomal guard cells in response to non-inductive ABA treatements. The goals set in the proposal were to characterize better how PFT (ERA1) affects ABA induced Ca2+ concentrations in guard cells and to identify putative CaaX box proteins which function as negative regulators of ABA signaling and which function is compromised in era1 mutant plants. To achieve these goals we proposed to use camelion Ca2+ sensor protein, high throughput genomic to identify the guard cell transcriptome and test prenylation of candidate proteins. We also proposed to focus our efforts of RAC small GTPases which are prenylated proteins which function in signaling. Our results show that farnesyltransferaseprenylates protein/s that act between the points of ABA perception and the activation of plasma membrane calcium influx channels. A RAC protein designated AtRAC8/AtRop10 also acts in negative regulation of ABA signaling. However, we discovered that this protein is palmitoylated and not prenylated although it contains a C-terminal CXXX motif. We further discovered a unique C-terminal sequence motif required for membrane targeting of palmitoylatedRACs and showed that their function is prenylation independent. A GC/MS based method for expression in plants, purification and analysis of prenyl group was developed. This method would allow highly reliable identification of prenylated protein. Mutants in the shared α subunit of PFT and PGGT-I was identified and characterized and was shown to be ABA hypersensitive but less than era1. This suggested that PFT and PGGT-I have opposing functions in ABA signaling. Our results enhanced the understanding of the role of protein prenylation in ABA signaling and drought resistance in plants with the implications of developing drought resistant plants. The results of our studies were published 4 papers which acknowledge support from BARD.