Stability of combining ability effects in maize hybrids

Abstract

General and specific combining ability effects are important indicators in a maize (Zea mays L.) breeding program aiming hybrid development. The objectives of the present study were to estimate the general (GCA) and specific combining abilities (SCA) effects of commercial maize hybrids using a complete diallel scheme and to assess the stabilities of these estimates. Fifty-five entries were assessed; ten commercial single-crosses and all possible double-crosses. The experiments were carried out in 12 environments in the 2005/06 growing season. A randomized complete block design was used with three replications per environment. Ear yield was evaluated, corrected to 13% of moisture content. The combined diallel analysis involving all environments was performed and the stability of general and specific combining ability effects was investigated. The underlying nonparametric statistics evaluated the contribution of each effect to the genotype by environment interaction. Non-additive effects were more important for this set of hybrids than the additive effects. It was possible to select parents with high stability for combining ability and with high GCA.

Combining ability of grain yield and agronomic traits in diverse maize lines with maize streak virus resistance for Eastern Africa region

“…There were significant differences among GCA and SCA effects for grain yield; both GCA (48.2%) and SCA (51.8%) were equally important for this trait (Table 3). The association of both GCA and SCA with grain yield concurs with other findings (Nass et al, 2000;Machado et al, 2009;Qi et al, 2010). The observation that GCA x location interaction was highly significant and greater than SCA x location interaction also agreed with other authors (Nass et al, 2000;Paterniani et al, 2000;Bello and Olaoye, 2009).…”

“…The observation that GCA x location interaction was highly significant and greater than SCA x location interaction also agreed with other authors (Nass et al, 2000;Paterniani et al, 2000;Bello and Olaoye, 2009). However, since SCA x environment interaction was generally non-significant, stability of SCA effects across environments was indicated as similarly observed by Machado et al (2009). Two parents, CML197 (0.919***) and CML202 (0.693***) had the highest positive and significant GCA for grain yield, and thus contributed positive alleles in the crosses in which they were involved (Table 4).…”

Combining ability for traits associated with yield and quality in super sweet corn (Zea mays L. saccharata)

“…These results have shown the prevalence of non-additive effects on corn ear yield (Table 1), as well as have corroborated the studies conducted by Machado et al (2009) and Santos et al (2014). On the other hand, the contribution from the GCA square sums to the ED and CD variables was relatively higher than that from SCA, fact that indicated the greater importance of additive effects and explained the 52.4% to 70.5% variation.…”

Partial diallel analysis among maize lines for characteristics related to the tassel and the productivity

“…The group II of lineages showed the highest estimates of GCA mean squares for the characters tassel and grain yield, indicating that there was a predominance of additive gene effects in all lineages of group II, being their estimates higher than the group I of lineages and the SCA estimates (Table 1). Estimates of the mean squares of SCA were higher than the GCA of the group I of lineages, indicating that the non-additive effects are most important for the variation in this set of hybrids, similar to the results of Machado et al (2009). In addition, the significant effects of specific combining ability (SCA) reported that there were different degrees of complementarity between the two heterotic groups for the assessed traits (Pinto et al, 2007).…”