Genetic basis of heterosis for grain yield and salinity tolerant traits in rice through diallel analysis

The present study was undertaken using a half diallel mating design in rice to evaluate the per se performance of parents and hybrids, along with the extent of heterosis (both heterobeltiosis and standard heterosis) for twelve traits, including grain yield per plant and salinity tolerant traits. The experimental material comprised eight genetically diverse parents and their twenty-eight F₁ hybrids (excluding reciprocals). Significant genetic variability was observed across all traits. Notable levels of heterobeltiosis and standard heterosis were recorded for most characters. On the basis of per se performance, parents TNR 1, NVSR 6531 and IR 55179 and hybrids GNR 3 × GR 19, NVSR 6526 × GR 19, NVSR 6531 × GR 19, GR 17 × GR 19 and NVSR 6531 × CSR 103-10-2 exhibited the maximum grain yield per plant. The highest standard heterosis for grain yield was observed in GNR 3 × GR 19 followed by NVSR 6526 × GR 19, NVSR 6531 × GR 19, GR 17 × GR 19 and NVSR 6531 × CSR 103-10-2, while the top heterobeltiosis values were recorded in GNR 3 × GR 19, NVSR 6526 × GR 19, GR 17 × GR 19, GNR 3 × CSR 103-10 2 and NVSR 6531 × GR 19. These promising hybrids also showed high heterosis for key yield-contributing traits such as panicle length, effective tillers per plant, grains per panicle and 100-grain weight, indicating the cumulative effect of these traits in enhancing grain yield.