Morphological and phenotypic variability in blackgram genotypes with varying reaction to Mungbean yellow Mosaic virus infection

Abstract

Sixteen blackgram [Vigna mungo (L.) Hepper] genotypes were screened for Mungbean yellow mosaic disease under field conditions and identified nine genotypes as resistant, as moderately resistant, four genotypes as susceptible and two as highly susceptible based on modified MULLaRP scale (0-9). No genotypes were found immune or highly resistant against yellow mosaic disease. Morphological characters namely leaf thickness, epicuticular wax content, trichome density and stomatal frequency were evaluated among the genotypes having different degree of resistance. Leaves of MYMV resistant genotypes were thick when compared to highly susceptible genotypes. Similarly, the amount of epicuticular wax and trichome density in resistant genotypes were comparatively high to that of highly susceptible genotypes. However, stomatal frequency was high in highly susceptible genotypes when compared to resistant genotypes. Significant negative correlation was observed among morphological characters with disease severity except the stomatal frequency which was positively correlated. Low disease severity were found in the genotypes with purple petiole colouration or purple splash and having resistant or moderately resistant reaction to MYMV infection while genotypes with green colour petiole were found to be either susceptible or highly susceptible.