Combining Ability in Wheat

Combining ability studies were carried out for grain yield and components of yield in wheat (Triticum aestivum L.) using the F₂ data from a 6 X 6 diallel set. The results were also compared with those reported earlier from the F₁ data (Paroda and Joshi, 1970). The correlation between the general combining ability effects obtained from the F₁ and F₂ data separately was highly significant for all the characters studied in two years, whereas the correlation between the specific combining ability effects was neigher high nor consistent. The results indicate that the F₂ generation can effectively be used for assessing the general combining ability. A marked decline in the estimates of specific combining ability variance and effects was observed in the F₂.

Grain yield was largely governed by dominance and the components of yield showed a preponderance of additive gene action. Both additive and dominance components showed interactions with the environment but the magnitude of the former was higher for all the characters studied.