Genetic diversity studies and identification of donors for lodging resistance in rice (Oryza sativa L.)

Rice (Oryza sativa L.) stands as the world’s primary food crop, and caters to the dietary requirements of countless individuals each day. Modernization of rice cultivation warrants the development of non-lodging rice cultivars which facilitate mechanical harvesting without loss of grains in the field. Lodging of rice is influenced by anatomical and chemical characteristics of the stem cell wall. In the present study, 54 rice genotypes were evaluated for morphological traits including plant characters determining stem strength like stem girth (SG), stem wall thickness (ST), and plant height. Diversity analysis based on quantitative traits categorized the 54 genotypes into nine clusters. The highest inter cluster distance was shown between cluster IV and cluster IX (12025.89) and the maximum intra-cluster distance was shown by cluster V. The Principal Component Analysis identified four PCs explaining 71.85% of the total variation. Histochemical staining for lignin deposition revealed that the genotype Rajamudi had dark red staining pertaining to more lignin content which is an indicator of lodging resistance. The germplasm was further analyzed using two SSR markers linked to Strong Culm Locus responsible for culm strength, the results confirmed that the following genotypes viz., Salem Channa, Vellai Chithiraikar, Vellai Kuruvai and Rajamudi might harbour the genes for strong culm. Besides molecular basis, morphological and histochemical studies also confirmed the lodging tolerance of these genotypes and can be employed as efficient donors to develop lodging-resistant varieties with high yield.