COMBINING ABILITY AND TYPE OF GENE ACTION FOR GRAIN YIELD AND OTHER ATRIBUTES IN MAIZE (Zea maize L.)

摘要

Eleven white maize inbred lines were top crossed to each of four different testers viz. Sd-7,Gm-14, Gm-22 and Gm-27 at Gemmiza Agric.Res.Staion during 2001 season . Forty four top crosses with 2 checks, SC-10 and SC-122 were evaluated at Gemmiza and Mallawy Agric.Res. Staions, ARC in 2002 season for days to 50 % silking, plant and ear height, no of ears/100 plant and grain yield ard/fed. Mean squares for crosses (C), lines (L), testers (T) and L x T were significant for all studied traits at both locations and combined. The interaction of crosses x locations was significant for all studied traits. Lines x Loc. and T x Loc. interaction was significant for all studied traits except, plant height for L x Loc. and ear height for T x Loc.. Furthermore, the interaction of L x T x Loc. mean squares was significant for all studied traits except, No. of ears/100 plants. The best GCA effects for grain yield were obtained for lines Gm-49 and Gm-60. These lines should be directly utilized in breeding programsto developed high yielding hybrids Results showed that 9 crosses showed positive and significant SCA effects for grain yield. The magnitude of delta ~2 GCA was larger for days to 50% silking, plant and ear height, while delta~2 SCA was larger for No. ofears/100 plants and grain yield. The interaction delta~2_(SCA) x L was high than that of delta~2_(GCA) x L for all studied traits, indicating that the non-additive type of gene action is more affected by environmental conditions than the additive type.