Combining ability analysis of fusarium head blight resistance in European winter wheat varieties

The aims of the present study were to estimate the general combining ability (GCA) and the specific combining ability (SCA) effects controlling type II FHB resistance across environments in a set of European winter wheat varieties and, for purposes of future selection, to identify potential combinations of parents with suitable levels of FHB resistance. Parental varieties as well as F ₁ generations were evaluated under both field and greenhouse conditions in two years. The results of the present study indicate that in the F ₁ generation mean DON content was relatively lowest after crossing of moderately resistant parents (Sakura/Bakfis, Sakura/Federer, Petrus/Bakfis, and Sakura/Petrus), and mean DON content is low also after crossing the moderately resistant Bakfis variety with the susceptible Biscay and Cubus varieties. Evaluation of crosses in the F ₁ generation was followed by evaluation of selected crosses (derived from the Bakfis and Sakura varieties) in the F ₂ generation. Correlations between F ₁ and F ₂ were highly significant in relation both to their DON content and visual symptom score (VSS), as well as between the individual experiments (and in the different years). The only exception was in the case of the 2014 field experiment, when inoculation was successful but conditions were not optimal for the disease to progress and DON to accumulate. The selection of a suitable parental variety (with a high GCA) can markedly influence the success rate of breeding for resistance to FHB. Detection of high SCA in the F ₁ generation is important for directing breeders to promising combinations for achieving FHB resistance. It was demonstrated here that low DON content may be achieved even after crossing a moderately resistant variety with susceptible varieties. Another possibility is to make use of heterosis directly for acquiring resistance in hybrid wheat (for decreasing DON content and manifestation of symptoms).