Morphological and biochemical characteristics associated with powdery mildew resistance in M3 population of blackgram (Vigna mungo (L.) Hepper)

Abstract

Powdery mildew (Erysiphe polygoni DC.) is one of the major diseases in blackgram during cold weather season which reduces up to 50 per cent of the yield. The present study deals with the morphological and biochemical characteristics such as trichome density, leaf thickness, stomatal density and total phenol, the enzyme activity of peroxidase and polyphenol oxidase in relation to powdery mildew resistance in blackgram. A total of 59 mutant families selected from the M 2 population were raised as M 3 based on powdery mildew score. Six mutant lines, viz., PM 27, PM 29, PM 48, PM 49, PM 42, PM 34 were identified as moderately resistant mutants against powdery mildew disease incidence based on field and glass house screening of visual scores. The resistant mutants showed higher trichome density, leaf thickness, total phenol content, the enzyme activity of peroxidase and polyphenol oxidase lower total sugar content and stomatal density than susceptible control (CO 6). These results clearly indicated the operation of resistance reaction in the identified mutants. However, the resistant check LBG 17 showed more resistance than the mutants. As the LBG 17 was photosensitive making it unsuitable for cultivation in all the seasons, the resistant mutants identified in this study may be used as resistance sources in place of LBG 17 for powdery mildew resistance studies.