Pakistan Journal of Biological Sciences1028-88801812-5735Asian Network for Scientific Information10.3923/pjbs.2006.1983.1986SofiParvez RatherA. G.VenkateshS. 102006910The success of any breeding strategy aiming at crop improvement relies heavily on action, interaction and linkage relationships of genes governing quantitative traits. The relative importance of additive, dominance and epistasis on grain yield and its component traits was studied in two promising maize hybrids viz., W3 x W5 and W3 x W8 by generation means analysis by developing six generations viz., P1, P2, F1, F2, BC and BC2. Both additive and dominance components were significant with predominance of latter indicating non-additive gene action for the expression of the traits studied, except for days to 75% husk browning and 100 seed weight in the crossW3 x W8 where only additive effects were significant. Among digenic interactions, additive x additive (i), additive x dominance (j) and dominance x dominance (1), types were significant for most of the traits in both crosses. Additive x additive and dominance x dominance interactions were greater than their corresponding additive and dominance components for most of the traits in both the crosses indicating thereby that epistasis was a significant contributor to genetic variances in both the crosses. However, additive x dominance type interaction was lesser than additive, dominance and other digenic interaction. The present study indicated presence of favorable epistatic gene combinations in both the hybrids i.e.,W3 x W5 and W3 x W8 and as such both have exhibited consistently better performance in evaluation trails. Gene action was found to be duplicate, for most of the traits in both crosses with notable exception of grains yield in W3 x W5. Thus it is suggested that reciprocal recurrent selection can be a viable breeding strategy in such situation as duplicate gene action is usually undesirable for hybrid breeding. However, continuous directional selection can lead to evolution of complementary gene action in genetically diverse inbred lines.]]>Atanaw-Alamnie, N., Y. Nayakar, M.C. Wal and A. Atanaw,200316131133Bateson, W.,1909Cavalli, L.L.,19521952pp: 135-144pp: 135-144Chahal, G.S., T.H. Singh and D.S. Virk,1991Chi, K.R., S.A. Eberhart and L.H. Penny,1969Zea mays L).]]>63511520Comstock, R.E., H.F. Robinson and H.H. Harvey,194941360367Doerksen, T.K., L.W. Kannenberg and E.A. Lee,20034316521658Eberhart, S.A., R.M. Moll, H.F. Robinson and C.C. Cockerham, 19666275280Eta-Ndu, J.T. and S.J. Openshaw,199939346352Gamble, E.E.,1962Zea mays L.): I. Separation and relative importance of gene effects for yield.]]>42339348Hallaur, A.R. and J.B. Miranda,19882nd Edn.,pp: 468pp: 468Hallauer, A.R.,199035116Kalla, V., R. Kumar and A.K. Basandrai,200122102106Lamkey, K.R., J.S. Bruce and A.E. Melchinger,19953512721281Mather, K.,1949Mather, K.,197432414419Melchinger, A.E., W. Schmidt and H.H. Gieger,198828743749Mihaljevic, R., H.F. Utz and A.H. Melchinger,20054526052613Phillips, P.C.,199814911671171Silva, J.C. and A.R. Hallaur,197566290296Wolf, D.P. and A.R. Hallauer,199737763770Yu, J. and R. Bernardo,200444405410Hayman, B.I.,195812371390