Estimation of genetic components for yield in rice using generation mean analysis

The nature of gene interaction in the inheritance of ten yield related traits was studied deploying generation mean analysis following six parameter model for parents (P1 and P2), F1, F2, B1 and B2 generations of two crosses in rice during wetseason. The results of the scaling tests revealed that the additive-dominance model was inadequate for all of the characters evaluated in both of the crosses, suggested the existence of epistasis in the inheritance of these characters. Additive gene effect [d] had significant contributions in both of the crosses for the expression of days to 50 per cent flowering, plant height, effective tillers per hill, spikelet per panicle, kernel length, kernel breadth, kernel L/B ratio and 1000-grain weight where as dominance [h] genetic effects was significant for all of the characters in both of the crosses except panicle length, effective tillers per hill and kernel breadth in cross I and days to 50 per cent flowering and grain yield per plant in cross II. The nature of epistasis was identified as duplicate in both of the crosses for all of the yield related traits. The present study demonstrates the importance of additive, dominance and epistatic gene effects for the inheritance of almost all the characters studied.