Genetic Effects Analysis in Direct and Reciprocal Crosses Between Lines from Two Germplasm Groups in Maize.

The objectives of the research study were to estimate genetic effects of lines, and to characterize selected crosses for grain quality traits in maize. Grain yield of single direct and reciprocal crosses between lines from two germplasm groups Dwarf (A) and normal Quality Protein Maize (QPM) (B) were evaluated in replicated experiments in two contrasting environments during 2006. A set of nine direct and reciprocal F₁ crosses were also characterized for grain physical and quality traits. Significant differences (P ≤ 0.01) between the two groups of crosses were found (AxB and BxA, respectively). The combination AxB showed the highest grain yield values with an average difference across sites of 31 percent regarding the reciprocal crosses (BxA). The combining ability estimates showed no consistent pattern effects, indicating that the way the line is used in the cross makes a specific combination response, which was also affected by the environment. In reciprocal crosses (BxA), hybrids showed an average performance for all grain quality traits, but were directly associated with starch gelatinization temperature. Nevertheless, line 19 (Group A) had a positive response on the favorable environment, whereas line 41 (Group B) had a consistent performance across environments, no matter if it is used as male or female. Specific combining ability estimates allowed identifying the crosses 19x41, 13x41, 19x52, 17x56, 19x56, 16x41 and 18x41 with good yield performance across the evaluation sites. Results indicated that lines from the Dwarf group should be used as female.