The present investigation in aromatic rice (Oryza sativa L.) was undertaken for studying the magnitude of gene action in four cross combination for yield and quality traits deploying generation mean analysis following six parameter model for parents (P1 and P2), F1, F2, BC1 and BC2 generations during three crop season. The results of the scaling tests revealed that the additive-dominance model was inadequate for all of the characters evaluated in all of the four crosses, suggested the existence of epistasis in the inheritance of these characters. On the basis of six parameters model, main effect viz., mean (m), additive (d) and dominance (h) and all three digenic interactions viz., additive x additive (i), additive x dominance (j) and dominance x dominance (l) were significant for grain yield per plant in cross-III (IET-26214 x GAR-1); for protein content in cross-III (IET-26214 x GAR-1) and cross-IV (IET-26215 x GNR-2); for amylose content in cross-II (IET-24617 x NWGR-9081); for milling in cross-III (IET-26214 x GAR-1); for hulling in all crosses except cross-I (GR-104 x IET-26215) indicated the involvement of additive, dominance as well as epistasis interaction for controlling this trait. The duplicate type epistasis was observed in majority of all traits in all crosses. The present study demonstrates the importance of additive, dominance and epistatic gene effects for the inheritance of almost all the yield as well as quality characters studied.

Key words: Aromatic rice, Gene action, Generation mean, Quality traits and Scaling test.