Estimation of combining ability and gene effect in maize lines using line tester analysis under drought stress conditions

To estimate general combining ability, specific combining ability and gene effect, 30 maize inbred lines were crossed with four male sterile testers. One hundred and twenty developed hybrids were planted in randomized complete block design with three replications in research field station of Seed and Plant Improvement Institute of Iran (SPII), Karaj, in 2009. Kernel yield, plant height, ear height, kernel number.row, row number.cob-1,kernel depth and 1000 kernel weight were measured. Analysis of variance, in both irrigation conditions, showed significant difference among hybrids for all characteristics except the row number.cob-1 in normal irrigation condition. Significant mean-square for line × tester implied that responses of lines and testers differed in two irrigation conditions. Evaluation of σGCA 2 σSCA 2 ⁄ indicated that there was greater dominance variance (SCA) than additive variance (GCA) for all traits.K3651/2, K47/2-2-1-3-1-1-1-1, K47/2-2-1-4-1-1-1-1, 47/2-2-1-21-2-1-1- 1, and K3640/8 inbred lines showed the highest GCA in the moisture stress condition. The highest SCA in the moisture stress condition was observed for T1×L18, T3×L30,T2× L23 and T4×L10 and the lowest SCA for T1×L7,T2×L30, T3×L26, T4×L23 combinations. Overall both additive and non-additive gene effects were involved in controlling of measured traits.