The effect of maize landraces and testers on the number of leaves above the ear in test cross hybrids

Abstract

The variation of the number of leaves above the ear in maize test cross hybrids was analyzed to identify superior combinations for this trait. The experiment involved crossing 31 maize landraces with three testers (L217, L73B013, and L255/75-5), representing different heterotic groups (Iowa Dent, BSSS and Lancaster). The general mean for the number of leaves above the ear was 6.18 leaves. The analysis of variance revealed that all sources of variation, including the environment, tester, landrace, and their interactions, were highly significant (p≤0.01), except for the triple interaction (p=0.964). The coefficient of variation was 6.00%, indicating low within-group variability. Maize landrace AN1569, across all testers, exhibited the highest number of leaves (6.72), suggesting its superior general combining ability for this trait. Other landraces, such as AN877, AN288, and AN197, also showed high values, predominantly belonging to dent maize types from late maturity groups. In contrast, the maize landrace AN1890, in test cross hybrids, produced the lowest number of leaves above the ear (5.76). Tester L73B013 contributed to hybrids with the highest number of leaves above the ear (6.31), compared to L217 and L255/75-5, which were statistically similar to each other. A positive correlation (r=0.782) was observed between the number of leaves above the ear in landraces per se and their general combining ability, emphasizing the additive genetic effects in the inheritance of this trait. These results emphasize the importance of specific landraces and testers in breeding programs aimed at improving the number of leaves above the ear, with potential implications for yield and adaptability