Impact of Genetic Divergence on the Ratio of Variance Due to Specific vs. General Combining Ability in Winter Triticale

The objective of our study was to examine the influence of genetic divergence on the ratio of the components of variance for specific (σ 2 SCA ) and general (σ 2 GCA ) combining ability using experimental data in triticale (xTriticosecale Wittm.). 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 σ 2 SCA and σ 2 GCA were determined for the total diallel and between the two subgroups. The ratio of σ 2 SCA VS. σ 2 GCA tended 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 σ 2 SCA vs. σ 2 GCA in situations with two genetically distinct populations than in situations with populations that are not genetically distinct.