Browsing by Author "Vikas Kumar Ravat"

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Antagonistic Yeasts for Biocontrol of the Banana Postharvest Anthracnose Pathogen Colletotrichum musae
(Blackwell Publishing Ltd, 2017) V. Yeka Zhimo; Darsana Dilip; Jessica Sten; Vikas Kumar Ravat; Dawa Dolma Bhutia; Birendranath Panja; Jayanta Saha
The biocontrol potentials of Candida tropicalis YZ1, C. tropicalis YZ27 and Saccharomyces cerevisiae YZ7 against the postharvest anthracnose pathogen Colletotrichum musae were investigated. Treatments with all the three biocontrol agents (1 × 108 CFU/ml) significantly reduced the natural anthracnose disease severity of harvested banana fruits stored at ambient condition. Germination and survival of C. musae spores were markedly inhibited by all the three yeast strains in in vitro tests. The niche overlap index (NOI) was used to determine the interaction between the antagonists and C. musae, and the results (high NOI values) suggest competitive exclusion of C. musae by the yeast strains. C. tropicalis YZ27 inoculated on banana wounds exhibited rapid colonization and maintenance of its population on the inoculated site. The biocontrol efficacy was also observed as a function of concentration of the antagonist applied. The fruits treated with C. tropicalis YZ27, 36 h before pathogen inoculation, showed the best results with 96.0% disease inhibition followed by those treated 24 h before with 84.0% inhibition. The above results point to competition for nutrients and space as the main mechanism of antagonistic action of C. tropicalis YZ27 against C. musae. © 2016 Blackwell Verlag GmbH
Genome-wide association study for powdery mildew resistance in CIMMYT's spring wheat germplasm
(John Wiley and Sons Inc, 2025) Deepa Bhadana; Prabhjot Kaur; Ramandeep P. Kaur; Vikas Kumar Ravat; Ashutosh; Rahul Kumar; Neeraj Kumar Vasistha
Powdery mildew (PM), caused by Blumeria graminis f. sp. tritici (Bgt), is a foliar disease of wheat (Triticum aestivum) that adversely affects both grain yield and quality. Growing resistant cultivars offers an effective and environmentally sustainable solution to managing PM. However, relying on the same genetic source of resistance can lead to resistance breakdown as Bgt isolates rapidly evolve. To mitigate this, identifying novel resistance sources is crucial. In this study, 225 diverse wheat genotypes were evaluated at adult plant stage in disease nurseries over the three crop seasons (2018/2019, 2019/2020 and 2020/2021). Using disease and genotyping data from 12,160 single-nucleotide polymorphism (SNP) markers, a genome-wide association study (GWAS) was conducted to identify novel resistance loci. We identified 22 marker loci significantly (at p < 0.005) associated with PM resistance, distributed across 14 wheat chromosomes (1A, 1B, 1D, 2A, 2B, 2D, 3A, 3B, 4A, 4B, 5D, 6A, 7A and 7B). Of these, seven loci overlap with previously identified regions, while the remaining 15 loci represent novel regions reported for the first time in this study. The identified SNP markers have significant potential for wheat breeding programmes, as they can accelerate the development of PM-resistant cultivars through marker-assisted selection. © 2024 British Society for Plant Pathology.
Genome-Wide Association Study Reveals Novel Powdery Mildew Resistance Loci in Bread Wheat
(Multidisciplinary Digital Publishing Institute (MDPI), 2023) Ramandeep Kaur; Neeraj Kumar Vasistha; Vikas Kumar Ravat; Vinod Kumar Mishra; Sandeep Sharma; Arun Kumar Joshi; Raman Dhariwal
Powdery mildew (PM), caused by the fungal pathogen Blumeria graminis f. sp. tritici (Bgt), significantly threatens global bread wheat production. Although the use of resistant cultivars is an effective strategy for managing PM, currently available wheat cultivars lack sufficient levels of resistance. To tackle this challenge, we conducted a comprehensive genome-wide association study (GWAS) using a diverse panel of 286 bread wheat genotypes. Over three consecutive years (2020–2021, 2021–2022, and 2022–2023), these genotypes were extensively evaluated for PM severity under field conditions following inoculation with virulent Bgt isolates. The panel was previously genotyped using the Illumina 90K Infinium iSelect assay to obtain genome-wide single-nucleotide polymorphism (SNP) marker coverage. By applying FarmCPU, a multilocus mixed model, we identified a total of 113 marker–trait associations (MTAs) located on chromosomes 1A, 1B, 2B, 3A, 3B, 4A, 4B, 5A, 5B, 6B, 7A, and 7B at a significance level of p ≤ 0.001. Notably, four novel MTAs on chromosome 6B were consistently detected in 2020–2021 and 2021–2022. Furthermore, within the confidence intervals of the identified SNPs, we identified 96 candidate genes belonging to different proteins including 12 disease resistance/host–pathogen interaction-related protein families. Among these, protein kinases, leucine-rich repeats, and zinc finger proteins were of particular interest due to their potential roles in PM resistance. These identified loci can serve as targets for breeding programs aimed at developing disease-resistant wheat cultivars. © 2023 His Majesty the King in Right of Canada.