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The objective of our study was to examine the influence of genetic divergence on the ratio of the components of variance for specific (σ2SCA) and general (σ2GCA) combining ability using experimental data in triticale (×TriticosecaleWittm.). In total, 21 lines and their 210 crosses were evaluated for grain yield in field trials. Published molecular data were reanalyzed, indicating an optimum of two subgroups. The estimates of σ2SCAand σ2GCAwere determined for the total diallel and between the two subgroups. The ratio of σ2SCAvs. σ2GCAtended to be lower for crosses between than within genetically distinct groups. Our experimental findings can be interpreted as an indicator of a more favorable ratio of σ2SCAvs. σ2GCAin situations with two genetically distinct populations than in situations with populations that are not genetically distinct.

The optimum allocation of breeding resources is crucial for the efficiency of breeding programmes. The objectives were to (i) compare selection gain ΔGkfor finite and infinite sample sizes, (ii) compare ΔGkand the probability of identifying superior hybrids (Pk), and (iii) determine the optimum allocation of the number of hybrids and test locations in hybrid maize breeding using doubled haploids. Infinite compared to finite sample sizes led to almost identical optimum allocation of test resources, but to an inflation of ΔGk. This inflation decreased as the budget and the number of finally selected hybrids increased. A reasonable Pkwas reached for hybrids belonging to the q = 1% best of the population. The optimum allocations for Pk(q)and ΔGkwere similar, indicating that Pk(q)is promising for optimizing breeding programmes.