Assessment of mungbean genotypes for durable resistance to mungbean yellow mosaic virus (MYMV)

Abstract

Mungbean (Vigna radiata (L.) Wilczek) is a vital pulse crop in India, often constrained by biotic stresses, amongwhich Mungbean Yellow Mosaic Virus (MYMV) is the most devastating, capable of causing up to 85 per cent yield loss. The present study was undertaken to identify stable sources of resistance to MYMV by evaluating 60 mungbean genotypesalong with four checks under natural epiphytotic conditions during the summer seasons of 2023 and 2024 at the Universityof Agricultural Sciences, Dharwad. The experimental design followed was an augmented block layout and disease scoringwas performed at 45, 60 and 75 days after sowing using a standard rating scale. Significant variation was observed amonggenotypes, with disease incidence (DI) ranging from 0 to 63.38 per cent in 2023 and 0 to 70 per cent in 2024. Analysis ofvariance indicated significant differences among entries, confirming genetic variability in disease response. Genotypes wereclassified into six disease response classes, from highly resistant to highly susceptible. Resistant checks, Vigna trilobata and IPM 2-14, exhibited consistent resistant to moderately resistant responses, while susceptible checks DGGV 2 and TARM1 showed highly susceptible and moderately susceptible reactions, respectively. Among the test entries, ‘Virat’ and ‘8BRD-9’ consistently exhibited resistant reactions across both seasons, indicating their potential as stable MYMV-resistantsources. DGGV 251-1 showed a moderately resistant response, likely due to its parentage involving the resistant cultivar IPM 2-14. The observed variation in disease response was attributed to genetic diversity among genotypes, seasonalvariability and differential vector pressure. These findings contribute valuable insights into utilization of MYMV-resistantgenotypes for future mungbean improvement programs.