COMBINING ABILITY FOR MAIZE WEEVIL PREFERENCE OF MAIZE GRAIN

Maize weevil (Sitophilus zeamais Motschulsky) can cause severe grain damage in maize (Zea mays L.). Knowledge of inheritance of weevils' preference would be helpful in designing breeding strategies to develop more tolerant/resistant cultivars. This study conducted to estimate general (GCA) and specific combining ability (SCA) for weevil preference/nonpreference. We used a 10-parent diallel cross in 1992 (Griffing's Method 3, Model 1). In 1993, due to insufficient seeds for some crosses, two eight-parent diallels (Griffing's Method 4, Model 1) were evaluated for GCA and SCA for maize weevil preference of maize grain. The two eight-parent diallels were subjects of the original 10-parent diallel. Second generation grain samples (100 g per plot) from F-1 crosses grown in the field were evaluated for maize weevil preference during 96-d (1992 experiment) and 108-d (1993 experiments) periods in the laboratory. The GCA, SCA, and reciprocal mean squares from the 10-parent diallel results from 1992 were significant. Both GCA and SCA were important in the analysis of the Subset 1 eight-parent diallel combined across years, whereas only GCA was significant in the Subset 2 eight-parent diallel combined across 1992 and 1993 data. Positive effects indicated non-preference and negative effects, preference of grain. Common parent means and GCA effects showed that L108 transmitted the most nonpreference and Mo17, the least nonpreference to its hybrids. In the 1992 data, significant positive GCA effects were detected in L108, L605, and L654; and significant negative GCA effects in B73, Mo17, L329, L729, and L266. Mo17 had a significant positive maternal effect (11.6), whereas B73 had a significant negative maternal effect (-11.93). The single cross Mo17 female x B73 male would posses more nonpreference than its reciprocal cross. Combined across years, analyses of two eight-parent diallel subsets of the original 10-parent diallel indicted GCA was more important than SCA inheritance of preference/nonpreference.