Revealing the Novel Genetic Resources for Blast Resistance in Diverse Rice Landraces of North-Eastern Hills of Himalayas

Rice blast disease is one of the most disastrous diseases causing significant losses to the crop. In the humid weather conditions of north-eastern Himalayan region, the situation is highly devastating as the climate is very favorable to the fungus Magnaporthe oryzae. Development of resistant rice varieties is the most effective, economical, and environment-friendly way to control this disease. The study aimed to identify novel sources of resistant donor using agro-morphological and gene-based markers for their utilization in development of blast-resistant varieties with high yield potential. Phenotypic evaluation has classified the hundred landraces into resistant (13), moderately resistant (43), moderately susceptible (24), and susceptible (20). Fifty-nine genotypes were found to carry genes responsible for blast resistance, either singly or in combination. The genotype MN-62 was found to have a blast score of zero in field screening. The genetic frequencies of the major blast resistance genes ranged from 28 to 97%. The cluster analysis grouped the landraces into three major groups. Additionally, the association between blast genes was computed with blast score using a general linear model (GLM) and mixed linear model (MLM), revealing that the markers AP4007, AP56595, C1454, and RM208 were found to be associated with the trait. The landraces with six blast R-genes like Nungshang Phou, Ratkhara, Anandhi, RCPL 1-44, Ching Phou Khong Nombi, MN-31, Rona Yang, and RCPL-128 were also superior for agro-morphological traits. Similarly, the landraces MN-62, Tara Bali, Rato Bhan Joha, MN-47, RCPL 1-411, and CAU-R1 were promising regarding yield and blast resistance. The resistant lines with various combinations of blast resistance genes can be utilized for introgression of genes into the commercial varieties for durable resistance using marker-assisted backcrossing.