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Shahryar F Kianian - One of the best experts on this subject based on the ideXlab platform.
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identification introgression and molecular marker genetic analysis and selection of a highly effective novel oat crown rust resistance from diploid oat Avena Strigosa
Theoretical and Applied Genetics, 2018Co-Authors: H W Rines, Marisa E Miller, M L Carson, Shiaoman Chao, Tyler Tiede, Jochum J Wiersma, Shahryar F KianianAbstract:Oat crown rust is one of the most damaging diseases of oat. We identified a new source of resistance and developed KASP and TaqMan markers for selection in breeding programs. A new highly effective resistance to oat crown rust (Puccinia coronata f. sp. Avenae) was identified in the diploid oat Avena Strigosa PI 258731 and introgressed into hexaploid cultivated oat. Young plants with this resistance show moderate susceptibility, whereas older plant tissues and adult plants are resistant with no virulent isolates encountered in over 8 years of testing. Resistance was incorporated into hexaploid oat by embryo rescue, colchicine chromosome doubling followed by backcrosses with a hexaploid parent, and selection for stable transmission of resistance. To mitigate flag leaf and panicle chlorosis/necrosis associated with the resistance, crosses were made with derived resistant lines to breeding lines of divergent parentage followed by selection. Subsequently, two F2 sister lines, termed MNBT1020-1 and MNBT1021-1, were identified in which the chlorosis/necrosis was reduced. These two lines performed well in replicated multi-location state trials in 2015 and 2016 out-yielding all cultivar entries. Segregating F2:3 plants resulting from crosses of MNBT lines to susceptible parents were genotyped with the oat 6K SNP array, and SNP loci with close linkage to the resistance were identified. KASP assays generated from linked SNPs showed accurate discrimination of the resistance in derivatives of the resistant MNBT lines crossed to susceptible breeding lines. A TaqMan marker was developed and correctly identified homozygous resistance in over 95% of 379 F4 plants when rust was scored in F4:5 plants in the field. Thus, a novel highly effective resistance and associated molecular markers are available for use in breeding, genetic analysis, and functional studies.
H W Rines - One of the best experts on this subject based on the ideXlab platform.
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identification introgression and molecular marker genetic analysis and selection of a highly effective novel oat crown rust resistance from diploid oat Avena Strigosa
Theoretical and Applied Genetics, 2018Co-Authors: H W Rines, Marisa E Miller, M L Carson, Shiaoman Chao, Tyler Tiede, Jochum J Wiersma, Shahryar F KianianAbstract:Oat crown rust is one of the most damaging diseases of oat. We identified a new source of resistance and developed KASP and TaqMan markers for selection in breeding programs. A new highly effective resistance to oat crown rust (Puccinia coronata f. sp. Avenae) was identified in the diploid oat Avena Strigosa PI 258731 and introgressed into hexaploid cultivated oat. Young plants with this resistance show moderate susceptibility, whereas older plant tissues and adult plants are resistant with no virulent isolates encountered in over 8 years of testing. Resistance was incorporated into hexaploid oat by embryo rescue, colchicine chromosome doubling followed by backcrosses with a hexaploid parent, and selection for stable transmission of resistance. To mitigate flag leaf and panicle chlorosis/necrosis associated with the resistance, crosses were made with derived resistant lines to breeding lines of divergent parentage followed by selection. Subsequently, two F2 sister lines, termed MNBT1020-1 and MNBT1021-1, were identified in which the chlorosis/necrosis was reduced. These two lines performed well in replicated multi-location state trials in 2015 and 2016 out-yielding all cultivar entries. Segregating F2:3 plants resulting from crosses of MNBT lines to susceptible parents were genotyped with the oat 6K SNP array, and SNP loci with close linkage to the resistance were identified. KASP assays generated from linked SNPs showed accurate discrimination of the resistance in derivatives of the resistant MNBT lines crossed to susceptible breeding lines. A TaqMan marker was developed and correctly identified homozygous resistance in over 95% of 379 F4 plants when rust was scored in F4:5 plants in the field. Thus, a novel highly effective resistance and associated molecular markers are available for use in breeding, genetic analysis, and functional studies.
A. L. Cabral - One of the best experts on this subject based on the ideXlab platform.
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Genetic analysis of seedling resistance to crown rust in five diploid oat (Avena Strigosa) accessions
Journal of Applied Genetics, 2016Co-Authors: A. L. Cabral, R F ParkAbstract:Crown rust, caused by Puccinia coronata Corda f. sp. Avenae Eriks., is a serious menace in oats, for which resistance is an effective means of control. Wild diploid oat accessions are a source of novel resistances that first need to be characterised prior to introgression into locally adapted oat cultivars. A genetic analysis of resistance to crown rust was carried out in three diverse diploid oat accessions (CIav6956, CIav9020, PI292226) and two cultivars (Saia and Glabrota) of A. Strigosa . A single major gene conditioning resistance to Australian crown rust pathotype (Pt) 0000–2 was identified in each of the three accessions. Allelism tests suggested that these genes are either the same, allelic, or tightly linked with less than 1 % recombination. Similarly, a single gene was identified in Glabrota, and possibly two genes in Saia; both cultivars previously reported to carry two and three crown rust resistance genes, respectively. The identified seedling resistance genes could be deployed in combination with other resistance gene(s) to enhance durability of resistance to crown rust in hexaploid oat. Current diploid and hexaploid linkage maps and molecular anchor markers (simple sequence repeat [SSR] and diversity array technology [DArT] markers) should facilitate their mapping and introgression into hexaploid oat.
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identification and genetic characterisation of adult plant resistance to crown rust in diploid and tetraploid accessions of Avena
Annals of Applied Biology, 2011Co-Authors: Davinder Singh, A. L. Cabral, R F ParkAbstract:The identification and genetic characterisation of adult plant resistance (APR) to crown rust, caused by Puccinia coronata f. sp. Avenae (Pca), was carried out in diploid Avena Strigosa and tetraploid Avena barbata accessions from diverse geographical regions. Seven accessions were found to carry APR to Pca, six of which (CIav6956, CIav7280, CIav8089, CIav9020, PI292226, PI436082) were diploid and one (PI337865) a tetraploid. All six diploid A. Strigosa accessions were postulated to carry the ‘Saia’ seedling resistance to Pca (Pc15, Pc16, Pc17) in addition to the APR. Three of these six accessions (CIav6956, CIav9020, PI292226) were used to study both seedling resistance and APR, using two Pca pathotypes, one avirulent on seedlings and the second virulent on seedlings but avirulent on adult plants. The seedling resistance in each was shown to be inherited independently of the APR. In each case, APR was conferred by a single major dominant gene, based on hypersensitivity, coupled with low infection types. Allelism tests are required to determine if these three APR genes are different. This is the first report of APR to crown rust in A. Strigosa and A. barbata.
R F Park - One of the best experts on this subject based on the ideXlab platform.
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Genetic analysis of seedling resistance to crown rust in five diploid oat (Avena Strigosa) accessions
Journal of Applied Genetics, 2016Co-Authors: A. L. Cabral, R F ParkAbstract:Crown rust, caused by Puccinia coronata Corda f. sp. Avenae Eriks., is a serious menace in oats, for which resistance is an effective means of control. Wild diploid oat accessions are a source of novel resistances that first need to be characterised prior to introgression into locally adapted oat cultivars. A genetic analysis of resistance to crown rust was carried out in three diverse diploid oat accessions (CIav6956, CIav9020, PI292226) and two cultivars (Saia and Glabrota) of A. Strigosa . A single major gene conditioning resistance to Australian crown rust pathotype (Pt) 0000–2 was identified in each of the three accessions. Allelism tests suggested that these genes are either the same, allelic, or tightly linked with less than 1 % recombination. Similarly, a single gene was identified in Glabrota, and possibly two genes in Saia; both cultivars previously reported to carry two and three crown rust resistance genes, respectively. The identified seedling resistance genes could be deployed in combination with other resistance gene(s) to enhance durability of resistance to crown rust in hexaploid oat. Current diploid and hexaploid linkage maps and molecular anchor markers (simple sequence repeat [SSR] and diversity array technology [DArT] markers) should facilitate their mapping and introgression into hexaploid oat.
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seedling resistance to puccinia coronata f sp Avenae in Avena Strigosa a barbata and a sativa
Euphytica, 2014Co-Authors: Adrian Lester Cabral, R F ParkAbstract:A study was carried out in which seedling resistance to the crown rust pathogen, Puccinia coronata f. sp. Avenae (Pca), was characterised among 385 oat accessions of Avena Strigosa, A. barbata and A. sativa from the USDA-ARS National Small Grains Collection. Accessions were tested with eight Australian pathotypes of Pca of diverse pathogenicity on a series of differential genotypes carrying known seedling resistance genes. Three diploid accessions, CIav2524, PI78821 and PI83721 of A. Strigosa, were highly resistant to all eight Pca pathotypes, and were postulated to carry Pc50 and Pc68, Pc91, or one or more new resistance genes. A total of 58 unidentified resistance specificities were detected among the tetraploid A. barbata accessions. All 58 resistances were ineffective against at least one of the Pca pathotypes and could therefore be novel. Additionally, evidence was obtained for the presence of genes Pc39 and Pc52 (in A. barbata and A. sativa accessions), Pc45 (in A. barbata accessions), Pc94 (in A. Strigosa and A. barbata accessions) and the “Saia” resistance (in A. Strigosa accessions).
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identification and genetic characterisation of adult plant resistance to crown rust in diploid and tetraploid accessions of Avena
Annals of Applied Biology, 2011Co-Authors: Davinder Singh, A. L. Cabral, R F ParkAbstract:The identification and genetic characterisation of adult plant resistance (APR) to crown rust, caused by Puccinia coronata f. sp. Avenae (Pca), was carried out in diploid Avena Strigosa and tetraploid Avena barbata accessions from diverse geographical regions. Seven accessions were found to carry APR to Pca, six of which (CIav6956, CIav7280, CIav8089, CIav9020, PI292226, PI436082) were diploid and one (PI337865) a tetraploid. All six diploid A. Strigosa accessions were postulated to carry the ‘Saia’ seedling resistance to Pca (Pc15, Pc16, Pc17) in addition to the APR. Three of these six accessions (CIav6956, CIav9020, PI292226) were used to study both seedling resistance and APR, using two Pca pathotypes, one avirulent on seedlings and the second virulent on seedlings but avirulent on adult plants. The seedling resistance in each was shown to be inherited independently of the APR. In each case, APR was conferred by a single major dominant gene, based on hypersensitivity, coupled with low infection types. Allelism tests are required to determine if these three APR genes are different. This is the first report of APR to crown rust in A. Strigosa and A. barbata.
P J Rayapati - One of the best experts on this subject based on the ideXlab platform.
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recombination within a 5 centimorgan region in diploid Avena reveals multiple specificities conferring resistance to puccinia coronata
Phytopathology, 1996Co-Authors: Roger P. Wise, P J RayapatiAbstract:A set of 100 recombinant inbred lines (RILs) was produced from a cross of diploid (n = 7) Avena Strigosa (CI 3815) with A. wiestii (CI 1994), resistant and susceptible, respectively, to Puccinia coronata, the causal agent of crown rust. This set of RILs was inoculated with 11 isolates of P. coronata. Infection type reactions to eight isolates (PC54, 263, 290, PC62, 202, 325A, PC58, and PC59) fit a 1:1 resistant/susceptible ratio expected for traits controlled by single genes. Reaction to isolate 264B fit a 3:1 resistant/susceptible ratio, suggesting resistance conditioned by two dominant genes. Reaction to isolate 276 fit a 1:3 resistant/susceptible ratio, suggesting control by two dominant genes, whereby one gene inhibits the resistance conferred by the other. All isolates detected resistance specificities that mapped to the Pca region in A. Strigosa for resistance to P coronata. Pca is positioned between the oat restriction fragment length polymorphism marker Xisu2192 and a new randomly amplified polymorphic DNA marker, XisuCl8, near the end of linkage group A. Five unique specificities within the Pca region were differentiated by recombination. The observation of five specificities conferring disease resistance that are linked in coupling is unusual, because such genes generally are linked in repulsion and inherited from multiple donor parents.
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placement of loci for avenins and resistance to puccinia coronata to a common linkage group in Avena Strigosa
Genome, 1994Co-Authors: P J Rayapati, V A PortyankoAbstract:Alcohol-soluble seed storage proteins of oat (avenins) were extracted from two diploid accessions representing the A genome and separated by high-resolution acid polyacrylamide gel electrophoresis. Polymorphisms were detected for three clearly resolved protein bands. Linkage analysis of 88 F2:3 families mapped the three bands to a single locus. Integration of avenin segregation data with an RFLP linkage map constructed from the same population, mapped the avenin locus to a linkage group containing a locus conferring resistance to nine isolates of Puccinia coronata. Linkage between genes encoding alcohol-soluble seed proteins and genes for resistance to Puccinia species was also observed for the homoeologous group 1 chromosomes of barley (1H), rye (1R), wheat (1A, 1B, 1D), and chromosomes 4 and 10 of maize.Key words: genetics, seed protein, disease resistance.
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a linkage map of diploid Avena based on rflp loci and a locus conferring resistance to nine isolates of puccinia coronata var Avenae
Theoretical and Applied Genetics, 1994Co-Authors: P J Rayapati, J W Gregory, Roger P. WiseAbstract:An F2 oat population was produced by crossing the diploid (n=7) species Avena Strigosa (CI 3815) with A. wiestii (CI 1994), resistant and susceptible, respectively, to 40 isolates of Puccinia coronata, the causal agent of crown rust. Eighty-eight F2 individuals were used to construct an RFLP linkage map representing the A genome of cultivated hexaploid oat. Two hundred and eight RFLP loci have been placed into 10 linkage groups. This map covers 2416 cM, with an average of 12 cM between RFLP loci. Eighty-eight F3 lines, derived from F2 individuals used to construct the map, were screened for resistance to 9 isolates of P. coronata. One locus, Pca, was found to confer a dominant resistance phenotype to isolates 203, 258, 263, 264B, 290, 298, 325A, and 345. Pca also conferred resistance to isolate 276; however, an unlinked second gene may also be involved.
