Screening of Finger Millet (Eleusine coracana L.) Germplasm for Blast Resistance under Field and Controlled Greenhouse Conditions Using AUDPC, AUCDC and Mahalanobis D2 Analysis

Abstract

Finger millet (Eleusine coracana L.), a vital staple crop, faces significant yield losses globally due to blast disease caused by Pyricularia oryzae. Deployment of resistant cultivars remains the most sustainable and cost-effective approach for disease management. Therefore, the identification of reliable resistance sources is critical for breeding programs aimed at developing durable blast-resistant varieties. In the present study, fifty-two diverse finger millet genotypes, including a known resistant check (Indaf-7) and a susceptible check (Uduru), were evaluated for leaf blast resistance during the Rabi season of 2022–2023 at the PG Research Farm, Centurion University of Technology and Management, Paralakhemundi, Odisha. Screening was conducted under both natural field conditions and controlled greenhouse environments supplemented with artificial pathogen inoculation. Disease severity was assessed using a standardized 0–9 disease rating scale, and quantitative measurements included calculation of the Area Under Disease Progress Curve (AUDPC). Additionally, the Area Under the Chlorophyll Decline Curve (AUCDC) was estimated using SPAD meter readings to quantify chlorophyll depletion associated with disease progression. Four genotypes—Bada Mandia, Lalsuru Mandia, VR 1233, and VR 1220—demonstrated robust resistance to blast infection. Meanwhile, a group of thirteen genotypes, including Telugu Mandia, Badtara, Dangardi, Chilli, Chaitanya, PR 202, VR 1220 FM, DPLM 3FM, VR 1214FM, CFMV1, VL 400FM, and FIN 6164, exhibited moderate resistance. Conversely, genotypes such as TNEC 1335FM, FIN 5167, Arjun, VR 1176, VR 1221, VR 1217, KMR 711, and FIN 5169 were identified as highly susceptible. The findings of this investigation offer a valuable genetic resource for finger millet breeding programs, laying a strong foundation for the development of cultivars with blast resistance and contributing to the sustainable production of this nutritionally important crop.