Assessment of soybean breeding lines from the all India coordinated research programme for agronomic traits and resistance to mungbean yellow mosaic India virus through field screening and artificial inoculation.

UNLABELLED: Yellow mosaic disease (YMD), caused by the mungbean yellow mosaic India virus (MYMIV), represents a significant threat to soybean production in Southeast Asia, particularly in India. This study assessed 230 soybean breeding lines from the All India Coordinated Research Programme (AICRP) for YMD resistance through multi-year field trials conducted at IARI, New Delhi, a hotspot location conducive to natural epiphytotic conditions for YMD. Disease impact was evaluated using the coefficient of infection (CI), which combines both percent disease incidence and severity grades, as well as the Area Under the Disease Progress Curve (AUDPC). Fifty-seven resistant genotypes proceeded to the advanced varietal trials (AVT1 and AVT2). Statistical analyses, including BLUP, WAASB, and WAASBY indices, identified SL 958 (WAASBY = 22.54) as the most resistant and stable genotype. Other promising highly resistant genotypes included NRC-137, SL 1074, PS 1572, SL 1028, DS 3106 and HIMSO 1690 all of which demonstrated favourable agronomic traits such as high yield, optimal plant height, seed weight, and maturity. Molecular characterization of the virus from infected samples collected at the YMD hotspot in New Delhi and the emerging hotspot in Dharwad confirmed the presence of the mungbean yellow mosaic India virus (MYMIV). The DNA-B sequence from the Dharwad isolate revealed a unique breakpoint through recombination analysis, indicating genetic variation between the isolates from the two locations. Highly resistant soybean lines identified through field testing were further validated for their resistance under controlled conditions using whitefly-mediated transmission and agroinoculation. All seven highly resistant lines were ultimately selected, as they exhibited no visible symptoms or minute yellow flecks under artificial inoculation conditions. qPCR analysis of five highly resistant genotypes indicated low accumulation of virus in comparison to susceptible controls. These findings will assist decision-makers in releasing these advanced soybean breeding lines into seed production chains for cultivation by farmers.

SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s12298-025-01614-1.