ABSTRACT

Soybean (Glycine max (L.) is an important legume and oil seed crop. It belongs to family Fabaceae. Yellow Mosaic Disease (YMD) is a major threat to soybean production. YMD is caused by Mungbean yellow mosaic virus (MYMV) and is transmitted by whitefly. It leads to 30-70 per cent yield loss. Experiment was carried out at MARS, University of Agricultural Sciences, Dharwad to know the incidence of YMD in different soybean growing regions of northern Karnataka, molecular characterization of virus, integrated management of YMD and screening of soybean genotypes against YMD. In kharif 2023, highest disease incidence was recorded in Belagavi district with average incidence of 11.22 per cent and least was recorded in Haveri district with average incidence of 9.04 per cent. Similarly, in summer 2024, Belagavi exhibited highest mean disease incidence of 20.23 per cent and least incidence of 19.36 per cent was recorded in Dharwad. YMD incidence was more during summer when compared to kharif season. Molecular characterization of virus revealed that MYMV specific cp-primers amplified a DNA fragment of length 652bp and isolate was found to be 99.53 per cent similar to the MYMV-Vijayapura mungbean isolate (PP470806.1). In phylogenetic tree, test isolate was grouped in cluster consisting of MYMV isolates and was closely related to MYMV-Vijayapura mungbean isolate. Among different treatments evaluated in field condition for integrated management of YMD using JS 335 variety, seed treatment with thiamethoxam 30FS @ 10ml/kg of seeds followed by two sprays of multineem 300ppm @ 10ml/l at 35 and 50 DAS respectively exhibited least disease incidence of 4.38 per cent along with high yield of 26.78 q/ha and benefit to cost ratio of 2.61. Among screened genotypes, DLSb 1 showed resistant (R) reaction, eleven genotypes showed moderately resistant (MR) reaction. Whereas, JS 335 exhibited susceptible (S) reaction.