GENERAL AND SPECIFIC COMBINING ABILITY OF TROPICAL MAIZE GERMPLASM

Abstract

Eight tropical maize populations were crossed in a diallel system. Parent and their 28 crosses were evaluated for grain yield in two plantations in 2006. The objective was to estimate the general combining ability (GCA) of the parental populations and the specific combining ability (SCA) of the crosses for grain yield. The populations were: 21, 22, 23, 25, 32, 43, 49 and the commercial variety VS-536. The Griffing method 2 design was utilized to estimate GCA and SCA effects, on a complete randomized block design with three replications, at two planting dates. The diallel analysis showed significant differences (P ≤ 0.01 y 0.05) among planting dates (PD), crosses (C), GCA, PD × C and PD × SCA interaction. Populations 23 and 43 showed the highest significant (P ≤ 0,01)  GCA, and the crosses VS 536 × Pob 32, Pob 22 × Pob 43, Pob 25 × Pob 49 y Pob 43 × Pob 49 showed the highest significant (P ≤ 0,01) SCA effects. Both high parent positive heterosis were observed for the crosses Pob 25 × Pob 49, Pob 43 × Pob 49 and Pob 22 × Pob 43. Populations 23 and 43 revealed potential to be used in maize breeding programs.