Morphometric and phenological variability and association of traits with reaction to Cercospora leaf spot in Mungbean (Vigna radiata [L.] R. Wilczek) cultivars

Mungbean is an important legume that contributes to food and nutritional security, especially in dryland agro-ecologies; however, its productivity is limited by a major biotic stress, Cercospora leaf spot (CLS). This study assessed morphometric and phenological variability and trait associations to identify mungbean cultivars with improved responses to CLS. A total of 64 mungbean cultivars were assessed across three locations during the 2024 and 2025 main cropping seasons using a randomized complete block design with three replications. The combined analysis of variance showed significant ( p < 0.05) to highly significant ( p < 0.001) variations among mungbean cultivars in almost all morphometric, phenological and CLS-disease-related traits. The assessed traits exhibited wide genetic variability, with genotypic and phenotypic coefficients of variation ranging from 4.30% (vegetative period) to 56.20% (economic growth rate). Ten of the 24 traits showed high broad-sense heritability (> 60%), of which seven also exhibited high genetic advance as percent of mean (> 20%), indicating their potential for effective selection in mungbean breeding. The correlation coefficient analysis revealed that majority of the morphometric and phenological traits exhibited strong and negative associations with CLS-related traits emphasizing the selective improvement for these traits could enhance CLS-resistance in mungbean cultivars. Among the cultivars, NVL-1 and MB-Temes produced the highest grain yield (2108.80 kg ha − 1 and 2020.00 kg ha − 1 , respectively) and exhibited moderate resistance to CLS-disease, making them promising cultivars for production in the study areas and other similar agro-ecologies. This study provides a framework for breeding CLS-resistant mungbean cultivars adapted to dryland areas.