Biochemical changes induced by mungbean yellow mosaic virus (MYMV) in blackgram (Vigna mungo) genotypes

in reaction to Mungbean Yellow Mosaic Virus (MYMV) infection. Based on modified MULLaRP scale (0-9), sixteen genotypes were screened for mungbean yellow mosaic disease under field conditions and recognized nine genotypes as resistant, one as moderately resistant, four genotypes as susceptible and two as highly susceptible. No genotypes were found immune or highly resistant to MYMV. Biochemical parameters namely, total phenols, total proteins, total chlorophyll, peroxidase and phenylalanine ammonia lyase activity were estimated among the genotypes having different degree of resistance. Upon infection, total phenols, total proteins content increased while total chlorophyll content decreased in all the genotypes. Genotype Co5 showed highest per cent increase (100.0%) of phenol content over corresponding healthy plants while it was least in DKU-102 (32.8%). The highest increase in protein content of diseased plants over corresponding healthy plants was observed in LBG-623 (53.9%) and the lowest was in KPU-21 (27.5%). Maximum reduction in chlorophyll content over the corresponding healthy plant was observed in OBG-32 (62.2%) while minimum reduction was recorded in KPU-21 (37.4%). The highest peroxidase activity over the corresponding healthy plant was recorded in KPU-21 (77.8%) upon MYMV infection. Maximum increase of PAL activity in diseased over corresponding healthy genotype was recorded in OBG- 32 (95.0%) and minimum in UG-218 (17.8%).