Identification of Powdery Mildew-Resistant Urdbean Genotypes through Field Assessment at Different Phenological Stages

Abstract

Powdery mildew caused by Erysiphe polygoni (DC)is one of the most economically important diseases in urdbean, and it occurs at later stages of crop growth, resulting in a yield loss of 20-50%. Powdery mildew control strategies include the use of chemicals and sources of host plant resistance. But due to the cost of chemicals, farmers rarely practice such control measures, and the usage of such fungicides will negatively affect the environment and especially human health. Therefore, the most effective way to control powdery mildew is the use of resistant varieties. Keeping this in view, disease screening studies were made to understand the identification of powdery mildew disease. Since powdery mildew may inflict heavy losses to the crop in the Telangana state, till now, none of the cultivars have been identified as resistant in Telangana against powdery mildew; therefore, this study was initiated to evaluate available urdbean germplasm for the identification of resistance sources to breed disease-resistant cultivars. In Rabi 2024-25, forty-nine genotypes were screened against powdery mildew diseases under field conditions along with susceptible and resistant checks. Out of 49 genotypes, none of the genotypes showed immune or resistant, five genotypes viz., MBG 1134, MBG 1169, MBG 1171, MBG 1123, and DBG 32-1 identified as moderately resistant, the remaining genotypes showed moderately susceptible (MBG-8, VBG 17-026) to highly susceptible (TU-512, PU-31, IPU 19-56, IPU 19-2).