Pathogenicity test of fungal pathogen causing foliar diseases in major cultivars (Vigna sp.) of Rajasthan
Abstract
Leguminous crops are crucial to sustainable agriculture and the second most important crop group after grasses (Poaceae). Greengram (Vigna radiata (L.) R.Wilczek) and black gram (Vigna mungo (L.) Hepper) are widely cultivated pulse crops across Asia during kharif, rabi and summer. Despite their agronomic and nutritional importance, productivity is often constrained by abiotic and biotic stresses. Continuous monocropping and intensive cultivation increase legume vulnerability to pathogens. Fungal diseases are a major constraint, causing approximately 10–25 % yield losses in legume crops. Foliar diseases also significantly reduce yield depending on crop growth stage, pathogen virulence, disease severity and prevailing environmental conditions. Important foliar diseases affecting Vigna species include anthracnose, Cercospora leaf spot and Corynespora leaf spot. The present study aimed to evaluate the pathogenicity of two important fungal pathogens, Colletotrichum truncatum (MTCC 2110) and Cercospora canescens (MTCC 10835), responsible for anthracnose and Cercospora leaf spot diseases, respectively. A pot experiment was conducted using commonly cultivated varieties of Vigna in Rajasthan, including V. radiata (MH1142 and IPM-205-7) and V. mungo (Pant Urad 31 and Kota Urad 3). Inoculation with the respective pathogens was performed and disease severity was assessed using the percent disease index (PDI). The results revealed variability in disease susceptibility among the tested cultivars. Vigna mungo cv. KU-3 exhibited comparatively lower disease severity against C. canescens with a percent disease index (PDI) of 24.50 ± 1.42, while Vigna radiata cv. IPM-205-7 showed lower susceptibility to Colletotrichum truncatum with a PDI of 48.77 ± 1.23. The fungal pathogens were re-isolated and molecular characterisation was done using universal primer (ITS 1F and ITS 4R) and the obtained sequences were submitted to National Centre for Biotechnology Information (NCBI). These findings suggest that these cultivars may be suitable for cultivation in regions of Rajasthan where the respective foliar diseases are prevalent. The use of resistant cultivars provides an effective and ecofriendly sustainable strategy for disease management and reducing dependence on chemical fungicides.