General and Specific Combining Ability Effects and their Interaction for Double Crossess in Studied Traits of Maize (Zea mays L.)


Six inbred lines that 1-S10, 2-Zn 12, 3- Sy24, 4- Zm17, 5- O18 and 6- Mgw76 of maize (Zea mays L.). Were used in this study using half diallel cross and produce 15 F1 single crosses. The single crosses were crossed a cording to Rawlings and Cockerham method and developed 45 double cross. Seeds of double crosses were cultivated to study combining ability and gene action for studied traits. The results showed highly significant differences for mean square of double crosses and for the all studied traits. The inbred lines 3 4 and 6 showed highest general combining ability effects for 250-grain weight, row number and grain yield per plant respectively. The double crosses due to the arrangement, t(13)-(25), t(13)-(46) and t(25)-(46) revealed highest specific combining ability effects for grain yield per plant. All characters were under the epistatic gene effect with type of gene action (Dominance *Dominance). While ear length, 250 grain weight were under epistatic gene effect with type of gene action (Additive*Additive). The effects of specific combining ability appeared more important than general combining ability effects in this study indicating the importance of dominance and Dominance * Dominance gen action in the inheritance of these traits.