Creating groups of maize genetic diversity for grain quality: Implications for breeding.

摘要

Characterization of crop genetic diversity aids in efficiently exploiting the allelic variation for genetic improvement of economically desirable traits. Maize (Zea mays L.) grain quality traits increase the value of end-use products. The objective of this research was to determine whether groups of genetic diversity could be identified for early maturity maize grain quality traits (percentage of protein, oil, and starch) and agronomic traits. Ten improved populations were crossed in a diallel mating design without reciprocals. Parents, their respective crosses, and a selected group of checks were evaluated in an 8x8 lattice design across eight environments. Combined analyses of variance showed significant differences among the genotypes for all traits studied, but none showed significance for average heterosis. No significant differences were found for protein content among parents. Narrow ranges were observed for the traits analyzed, particularly for grain quality traits. General combining ability (GCA) effects were more important for grain oil concentration than grain protein and starch concentrations while specific combining ability (SCA) effects were larger for protein and starch concentration than oil concentration. Clustering analysis showed the presence of five diversity groups based on their breeding origin. These results support breeding efforts towards the genetic improvement of grain quality traits in the U.S. northern Corn Belt.