Field Based Disease Indexing of Soybean Genotypes Against Yellow Mosaic Virus

Abstract

Yellow Mosaic Virus (YMV) is a major biotic constraint to soybean (Glycine max L. Merrill) production in India, significantly reducing yield and productivity. To identify resistant sources and characterize genetic variability for YMV resistance, a field experiment was conducted during the Kharif 2023 at the experimental field, Department of Genetics and Plant Breeding, College of Agriculture, RVSKVV, Gwalior, Madhya Pradesh, India. Ninety-two diverse soybean genotypes, including three checks viz., JS 20-98, JS20-34 and RVSM 2011-35, were evaluated under natural epiphytotic conditions using a Randomized Block Design with two replications. Spreader rows of the highly susceptible variety JS335 were also planted to ensure uniform YMV inoculum pressure. Disease severity was scored based on a standardized 0–5 scale, wherein lower scores indicated higher resistance. Substantial variability was evident in disease response, with genotypes categorized as highly resistant, resistant, moderately resistant, moderately susceptible, susceptible and highly susceptible. Genotypes such as RVS 23-1, RVS 23-8, JS20-98, PS1693 and PS1696 exhibited higher levels of resistance, remaining asymptomatic or showing negligible symptoms. In contrast, genotypes viz., JS335 and RVS2001-4 displayed high susceptibility, validating their role as spreader lines. The identification of genotypes with moderate to high resistance highlights their potential utility in breeding programmes. These findings provide a valuable foundation for the development of YMV-resistant soybean cultivars in future. Integration with molecular markers and gene expression studies may accelerate resistance breeding and contribute to sustainable soybean cultivation in YMV-endemic regions.