Browsing by Author "Ram Narayan Ahirwar"

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Biplot analysis for spot blotch and yield trait using wami panel of spring wheat
(Editorial board of Journal of Experimental Biology and Agricultural Sciences, 2020) Ram Narayan Ahirwar; Vinod Kumar Mishra; Dwijesh Chandra Mishra; Neeraj Budhlakoti; Shweta Singh; Ramesh Chand
Wheat (Triticum aestivum L.) is a staple food worldwide. Spot Blotch (SB) has been a major disease for cultivation of wheat in Eastern Gangatic Plain (EGP). The goal of this study was to evaluate genetically diverse, advanced elite lines of wheat association mapping initiative (WAMI) population to identify useful genetic diversity and other related traits for spot blotch resistance present in WAMI panel for wheat improvement. A panel of 289 elite lines of WAMI population were assessed for spot blotch resistance, days to heading and plot yield for three consecutive years (2012-13, 2013-14 & 2014-15). The significant differences among genotype, year and genotype × year for area under disease progress curve (AUDPC), days to heading and plot yield were exhibited. The negative correlation between days to heading and spot blotch AUDPC was observed whereas, AUDPC and days to heading was significantly and negatively correlated with plot yield. Based on GGE biplot, the first two principal components explained 100%, 100% and 84.5% of the total variation for AUDPC, days to heading and plot yield respectively. Germplasms 9122, 9049 and 9239 were showed most resistant under study. The highest mean value for plot yield was observed for the panel 9061, 9070, 9203, 9216, 9118 and 9227 which were found relatively more stable for grain yield. These genotypes could be used in wheat improvement programmes for developing superior genotypes for yield and spot blotch resistance contributing to food security in south Asia. © 2020, Editorial board of Journal of Experimental Biology and Agricultural Sciences. All rights reserved.
Genetic characterization for lesion mimic and other traits in relation to spot blotch resistance in spring wheat
(Public Library of Science, 2020) Shweta Singh; Vinod Kumar Mishra; Ravindra Nath Kharwar; Neeraj Budhlakoti; Ram Narayan Ahirwar; Dwijesh Chandra Mishra; Sundeep Kumar; Ramesh Chand; Uttam Kumar; Suneel Kumar; Arun Kumar Joshi
Lesion mimic (Lm) mutants display hypersensitive responses (HR) without any pathogen attack; their symptoms are similar to those produced by a pathogen and result in cell death. In wheat, such mutants have been reported to be resistant against leaf rust due to their biotrophic nature. However, Lm mutants tend to encourage spot blotch (SB) disease caused by Bipolarissorokiniana since dead cells facilitate pathogen multiplication. In this study, 289 diverse wheat germplasm lines were phenotyped in three consecutive growing seasons (2012–2015). Genotype data was generated using the Illumina iSelect beadchip assay platform for wheat germplasm lines. A total of 13,589 single-nucleotide polymorphisms (SNPs) were selected andused for further association mapping. Lm was positively associated with Area Under Disease Progress Curve (AUDPC) for SB but negatively with glaucous index (GI), leaf tip necrosis (Ltn) and latent period (LP). Ltn had a negative association with AUDPC and Lm but a positive one with LP. In a genome-wide association study (GWAS), 29 markers were significantly associated with these traits and 27 were an notated. Seven SNP markers associated with Lm were on chromosome 6A; another on 1B was found to be linked with Ltn. Like wise, seven SNP markers were associated with GI; one on chromosome 6A with the others on 6B. Five SNP markers on chromosomes 3B and 3Dwere significantly correlated with LP, while nine SNP markers on chromosomes 5A and 5B were significantly associated with AUDPC for SB. This study is the first to explore the interaction in wheat between Lm mutants and the hemibiotrophic SB pathogen B.sorokiniana. Copyright: © 2020 Singh et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Genome-wide association mapping of spot blotch resistance in wheat association mapping initiative (WAMI) panel of spring wheat (Triticum aestivum L.)
(Public Library of Science, 2018) Ram Narayan Ahirwar; Vinod Kumar Mishra; Ramesh Chand; Neeraj Budhlakoti; Dwijesh Chandra Mishra; Sundeep Kumar; Shweta Singh; Arun Kumar Joshi
Spot blotch (SB) caused by Bipolaris sorokiniana, is one of the most important diseases of wheat in the eastern part of south Asia causing considerable yield loss to the wheat crop. There is an urgent need to identify genetic loci closely associated with resistance to this pathogen for developing resistant cultivars. Hence, genomic regions responsible for SB resistance were searched using a wheat association mapping initiative (WAMI) panel involving 287 spring wheat genotypes of different origin. Genome-wide association mapping (GWAM) was performed using single nucleotide polymorphism (SNP) markers from a custom 90 K wheat SNP array. A mixed linear model (MLM) was used for assessing the association of SNP markers with spot blotch resistance in three consecutive years. Three traits were measured: incubation period, lesion number and area under the disease progress curve (AUDPC). Significant SNP markers were found linked to five, six and four quantitative trait loci (QTLs) for incubation period, lesion number and AUDPC respectively. They were detected on 11 different chromosomes: 1A, 1B, 1D, 4A, 5A, 5B, 6A, 6B, 6D, 7A, 7B with marker R 2 range of 0.083 to 0.11. The greatest number of significant SNP-markers was found for lesion number and AUDPC on chromosome 6B and 5B, respectively, representing a better coverage of B-genome by SNPs. On the other hand, the most significant and largest SNP markers for incubation period were detected on 6A and 4A chromosomes indicating that this trait is associated with the A-genome of wheat. Although, QTLs for spot blotch resistance have been reported in wheat on these same chromosomes, the association of incubation period and lesion number with SB resistance has not been reported in previous studies. The panel exhibits considerable variation for SB resistance and also provides a good scope of marker-assisted selection using the identified SNP markers linked to resistant QTLs. Copyright: © 2018 Ahirwar et al.
Spot blotch disease of wheat as influenced by foliar trichome and stomata density
(Elsevier B.V., 2021) Shiwarttan Kumar Gupt; Ramesh Chand; Vinod Kumar Mishra; Ram Narayan Ahirwar; Madhav Bhatta; Arun Kumar Joshi
Spot blotch, caused by Bipolaris sorokiniana, is a potent biotic constraint to wheat crop leading to substantial yield abatement in warm humid South Asia (e.g. India, Nepal and Bangladesh) and other major wheat-growing countries such as Canada, the United States, Brazil and Australia. A set of 98 bread wheat genotypes were evaluated over two growing seasons to investigate the relationship among foliar trichome, stomata density, and susceptibility to the spot blotch pathogen. The higher density of trichomes (90-140 mm−2) on the adaxial surface of flag leaves entrapped 32-74 mm−2 pathogen spores. It restricted the dew droplets size (0.15–0.3 mm2) on the flag leaves and thus prevented direct contact between the spores and the leaf epidermis. Trichome density was negatively associated with the disease development and spore germination but positively associated with grain size and the number of spores entrapped on trichomes per mm2. Conversely, stomata density was positively associated with the development of the disease. Cluster and principal component analyses divided trichome density, the number of spores trapped on trichome per mm2, and thousand grain weight into one group and stomata density, the area under disease progress curve, percent spore germination, and dew scale into another group. The results from this study provided a novel insight to breeders where the selection of bread wheat genotypes with high trichome (90-140 mm−2) and low stomata density (72-90 mm−2) on foliage could enhance spot blotch resistance in wheat. © 2021