DIALLEL ANALYSIS OF YELLOW MAIZE FOR COMBINING ABILITY AND HETEROSIS

One way cross among developed seven yellow maize inbred lines was made at Gemmeiza. Agricultural Research Station during 2006 growing season. Parents, their F1 crosses and four yellow single crosses i.e. checks (SC 155, SC 162, SC 164 and SC 3084 ) were evaluated at Gemmeiza and Sids Agricultural Research Stations in 2007 growing season. Data were recorded for grain yield , days to 50 % silking, plant and ear heights , ear position , resistance to late wilt and number of ears/plant. Data were analyzed according to method-2 model-1 procedure Griffing (1956). The results indicated that mean squares due to locations were significant for all traits, except resistance to late wilt. Genotypes mean squares, their partitions and their interaction with locations were significant for most studied traits . General and specific combining ability (GCA and SCA) mean squares were significant for all of the studied traits. The magnitude of GCA / SCA ratio less than the unity indicating that the non-additive and additive gene action are more important for the studied traits. Significant interaction between locations and both types of combining ability were detected for all traits except number of ears /plants . The inbred line Gm.209 has positive GCA effects for earliness and short plants, moreover the inbred line Gm. 206 exhibited desirable and positive GCA effects for resistance to late wilt and grain yield traits. four crosses Gm.220 x Gm. 205 (33.91), Gm.220 x Gm.203 (33.37), Gm.206 x Gm.203 (33.51) and Gm.206 x Gm.220 (33.31) ard/fed show significantly positive heterotic effects relative to commercial hybrid SC 162 (30.26) ard/fed . These crosses could be advanced to the second evaluation steps for releasing as promising hybrids in maize breeding program.