First insights into the quantitative genetic composition of the female seed yield for an efficient hybrid seed production in wheat (Triticum aestivum L.)

Hybrid breeding of wheat (Triticum aestivum L.) is limited by its self-pollinating nature. Past cross-pollination improvements mostly focused on optimizing male traits. We tested the hybrid seed yield of 100 diverse elite lines treated with a chemical hybridization agent (CHA) and pollinated by non-sterilized male plants in multi-environmental field trials. Plant height and phenological traits of female plants were also assessed. In parallel, control experiments without CHA sterilization were conducted to measure per se yield of the tested material. Hybrid seed yield variation is of quantitative genetic nature, and, despite the large environmental influence, this trait has a strong genotypic component and is highly heritable (h(2) = .77). The lack of correlation between hybrid seed yield and per se yield suggests a non-shared genetic control. Phenological traits and their interactions are important factors explaining together similar to 1/3 of hybrid seed yield variation. In contrast to plant height and flowering traits, which are influenced by major genetic factors, no significant marker-trait associations were found for the hybrid seed yield, thus suggesting a highly polygenic genetic architecture and the need of larger populations to investigate female hybrid seed yield.