Identification of Superior Transgressive Segregants from Intercrossing the Interspecific Crosses between Oryza sativa and Oryza rufipogon

Abstract

Rice (Oryza sativa L.) is the primary staple food for more than half of the world's population, making the development of high-yielding cultivars essential for global food security. The present study evaluated genetic variability, heritability, genetic advance, character associations, and principal components in an F₂ segregating population comprising 133 individual plants derived from the cross NPA-109 × DRR Dhan 74. The population was evaluated during Kharif 2025 at the research farm of the ICAR–Indian Institute of Rice Research (ICAR-IIRR), Hyderabad. Five quantitative traits—plant height, number of tillers per plant, productive tillers per plant, panicle length, and grain yield per plant—were recorded. Phenotypic and genotypic coefficients of variation, broad-sense heritability, genetic advance as a percentage of the mean, Pearson's correlation, and principal component analysis were used to assess the genetic architecture of the population. The phenotypic coefficient of variation was consistently slightly higher than the genotypic coefficient of variation, indicating minimal environmental influence on trait expression. High heritability coupled with high genetic advance was observed for grain yield per plant, productive tillers, and number of tillers, suggesting the predominance of additive gene action and the potential effectiveness of direct selection. Correlation analysis and principal component analysis identified panicle length and productive tillers as important contributors to grain yield. Continuous frequency distributions further indicated quantitative inheritance and extensive genetic recombination within the population. Superior transgressive segregants, particularly DBN-25-2-1 and DBN-25-7-10, exhibited high grain yield and represent valuable breeding material for advancement to subsequent generations and the development of high-yielding rice cultivars.