Inheritance Analysis of Grain Yield and Contributing Traits in Rice Through Six Populations Under Normal and Water Deficit Conditions

Inheritance of yield and yield contributing traits for three crosses namely Sakha 108/IET 1444, Sakha 104/IRAT 170, and Sakha 107/Moroberekan were used to evaluate six populations including P1, P2, F1, F2, BC1, and BC2 for each cross. Scaling test results highlighted the importance of epistatic interactions for all the studied traits in the three crosses. Significant negative additive gene effects were observed under normal and water deficit conditions for most traits across the three crosses. There were some exceptions regarding the days to heading, which did not show significant effects for the first and second crosses under normal conditions, as well as for the first cross under water deficit conditions. However, all three crosses under normal conditions significantly affected grain yield per plant. In contrast, for the third cross under water deficit conditions, the effects were both significant and highly significant under positive gene action. The majority of traits exhibited positive and significant heterosis over the mid and better parents, except the second cross on fertility percentage and the third cross on heading date, which showed negative and highly significant heterosis. The heritability values in the narrow sense were found to be low to moderate for all the traits studied. These values ranged from 27.24% for grain yield per plant in the first cross to 57.74% for 100-grain weight in the third cross under normal conditions. Under water stress conditions, the dominance effect was found to play a significant role in the inheritance of these traits.