Breeding strategies for seed protein content and trypsin inhibitors inferred from combining ability and heterosis in test‐crosses of Vicia faba

Abstract

AbstractThe relative importance of general and specific combining ability (GCA and SCA, respectively), amount and causes of heterosis and inferences for breeding strategies were assessed for trypsin inhibitors activity (TIA) and seed protein content (SPC) in Vicia faba test‐crosses. Four lines with low (‘Bond’) and high (‘H2OS’, ‘98/Tunesien’ and ‘Canner Express’) TIA, and two testers (‘Rowena’ and ‘Felicia’) with low TIA were used to produce test‐crosses. GCA accounted for 89% and 57% of the test‐cross sums of squares for SPC and TIA, respectively; SCA accounted for 48% and 34%, and differences between reciprocals for 6% and 9%. Specific heterosis was large only in low TIA × low TIA test‐crosses and tended towards an increased TIA. Epistatic interaction explained the observed specific heterosis for high TIA. Breeding faba bean hybrids for high SPC and low TIA is not convenient because non‐additive gene actions exert minimal effects on SPC or are in the undesired direction for TIA. Selecting inbred lines which combine low TIA, good SPC and satisfactory grain yield is more promising] Rowena and Rowena × Bond are adequate as base materials.