Screening of blackgram (Vigna mungo) genotypes for resistance to cercospora leaf spot and yield performance in Nepal

Abstract

This study screened 12 black gram (Vigna mungo L.) genotypes for resistance to Cercospora leaf spot (CLS) caused by Cercospora canescens. Conducted at the research plot of the Mid-West Academy and Research Institute, Tulsipur, Dang, the experiment utilized a randomized complete block design with three replications from September 2022 to January 2023. Disease severity was evaluated at 40, 47, and 54 days after sowing (DAS), with scoring based on the percentage of infected leaf area at 7-day intervals. Key disease metrics—incidence, severity, mean area under the disease progress curve (AUDPC), and yield—were calculated. Results indicated no significant difference in CLS incidence among genotypes. However, significant differences in disease severity were noted at 40, 47, and 54 DAS, with AUDPC values differing across genotypes. Based on mean AUDPC values, 10 genotypes were categorized as moderately resistant, while BLG 0066-1-1 and BLG 0035-1 were moderately susceptible. BLG 0035-1 had the highest AUDPC (324.1), and BLG 0069-1 had the lowest (175). Yield varied significantly, with the highest yield (799 kg/ha) recorded for BLG 0068-2 and the lowest (495 kg/ha) for BLG 0066-1. These findings support breeding efforts targeting CLS resistance and enhanced yield in black gram.