Identification of mung bean germplasm for resistance against Cercospora canescens and to study the association of biochemical parameters with defense mechanisms

Abstract

AbstractSizable loss in crop yields resulting from Cercospora leaf spot (CLS), caused by Cercospora canescens and is a major disease in mung bean [Vigna radiata (L.) R. Wilczek] crops, demands a thorough evaluation of various parameters dealing with the infection. Determination of components for CLS resistance is associated with leaf spot intensity in the field, which is estimated from the area under the disease progress curve (AUDPC). The present study showed that out of 261 genotypes screened in the field for CLS, 88, 89, 51 and, 33 genotypes were found to be resistant, moderately resistant, moderately susceptible, and susceptible, respectively, on the basis of the AUDPC values. Further, five resistant and five susceptible genotypes were selected from the screened genotypes for bioassay analysis and were subjected to artificial inoculation with three different isolates of Cercospora canescens to study the effectiveness in polyhouse. The morphological data along with disease incidence, chlorophyll content, proline content, phenol content and enzymatic activities of phenylalanine ammonia‐lyase (PAL), peroxidase (POX), and superoxide dismutase (SOD) were estimated. The findings showed that there was a significant increase in the enzymatic activities, total phenol, and proline contents in inoculated resistant and susceptible genotypes vs. control (without inoculation). However, the total chlorophyll content reduced in both resistant and susceptible genotypes after inoculation. Moreover, higher enzyme activities were marked in the resistant genotypes than the susceptible genotypes. This study will help to identify the resistant and susceptible mung bean genotypes against Cercospora canescens for further agronomic study as well as breeding programs.