How do eyespot resistance genes transferred into winter wheat breeding lines affect their yield?

摘要

: Eyespot can reduce yields, even up to 50%. There are four genetically characterized resistances in wheat varieties, controlled by: (1) the Pchl gene, transferred from Aegilops ventricosa; (2) the Pchl gene, originating from wheat variety Capelle Desprez; (3) the Pch3 gene, originating from Dasypyrum vilhsum; and (4) the Q.Pch.jic-5A gene, a quantitative trait locus (QTL) located on chromosome 5A of Capelle Desprez. However, those loci have drawbacks, such as linkage of Pchl with deleterious traitsand limited effectiveness of Pchl against the disease. Here we present an initial study which aims to characterize wheat pre-registration breeding lines carrying 12 eyespot resistance genes, consider their resistance expression in inoculation tests and the influence of resistance genotypes on the yield. We selected four groups of breeding lines, carrying: (1) the Pchl gene alone: one line; (2) the Pchl gene alone: four lines; (3) the Q.Pch.jicSA gene alone: one line; and (4) Pchl + Q.Pch.jicSA: three lines. For the first time, the effect of the combination of Pchl and Q.Pch.jicSA genes was compared with resistance conferred by Pchl or Q.Pch.jicSA alone. We found significant differences between infection scores evaluated in resistant lines carrying Pchland Q.Pch.jicSA alone, while no differences in terms of the level of resistance expression were detected between Pchl alone and Pchl + Q.Pch.jicSA, and between wheat lines carrying Pchl and Pchl alone. Moreover, we demonstrated that the Pchl gene, together with an Ac ventricosa segment, caused statistically significant yield losses, both as a single eyespot resistance source or in a combination with Q.Pch.jicSA. Yield scores showed that wheat lines with Q.Pch.jicSA had the highest yields, similar to the yielding potential of Pc/i2-bearing lines and control varieties.