Exploitation of Heterosis for Yield, Yield Components and Quality Traits in Rice (Oryza sativa L.) Using Line × Tester Mating Design

Abstract

Increasing grain yield remains a primary objective in rice breeding to ensure global food security. Heterosis, which exploits the superiority of F₁ hybrids over their parents, is among the most effective genetic tools for achieving yield gains. The present study was conducted at the Regional Agricultural Research Station, Polasa, Jagtial district, Telangana, India, with the objective of estimating heterosis for yield, yield component and quality traits in rice (Oryza sativa L.). Four cytoplasmic male sterile (CMS) lines were crossed with eight testers following a line × tester mating design during kharif 2022, generating 32 hybrids. These hybrids, along with their parents and two check varieties (KPH 4 and KPH 468), were evaluated in a randomised block design with three replications during rabi 2022–23. Observations were recorded on 13 characters, comprising days to 50 per cent flowering, plant height, panicle length, number of productive tillers per plant, number of filled grains per panicle, 1000-grain weight, grain yield per plant, kernel length, kernel breadth, kernel length-breadth ratio, hulling percentage, milling percentage and head rice recovery. Analysis of variance revealed significant differences among genotypes for all characters studied. Heterosis estimates for mid-parent, better-parent and standard checks were variable across crosses and characters. Heterosis for grain yield per plant was attributed to the simultaneous expression of heterosis across multiple yield component traits. The highest standard heterosis for grain yield per plant was recorded in CMS 23A × IR 65514-5-2-19R-1 (32.09% over KPH 4; 16.20% over KPH 468), CMS 14A × IR 65483-14-1-1-4-13R, CMS 64A × IR 65514-5-2-19R-1, CMS 64A × JGL 29651, and CMS 64A × IR 63870-7-3-2-3-3R. Notably, CMS 14A × IR 65483-14-1-1-4-13R also exhibited the highest standard heterosis for head rice recovery (34.63% over KPH 4; 55.64% over KPH 468). These promising hybrids warrant further evaluation across locations and seasons prior to commercial release.