Development of valuable wheat inbred lines through the introduction of Dasypyrum villosum germplasm in their pedigree

Abstract

Selection of improved stable wheat inbred lines for low input production systems was achieved through the relevant combination of wheat and Dasypyrum villosum (Dv) germplasm using two approaches: (1) a re-evaluation of a tri-parental species breeding scheme, and (2) a modified bulk-breeding method. Both methods optimized selection outcome. The first breeding method was based on the synthesis of a T. turgidum var durum Dv hexaploid amphiploid, and crossing of that amphiploid to a bread wheat cultivar. The second breeding method was developed by bulk harvesting seeds from F1 and F2 from each biparental combination involving commercial wheat cultivars and wheat introgression breeding lines (IBLs) containing various amount of chromatin from Dv. In the first case, the M V amphiploid displayed typical adaptive traits of Dv such as high resistance to diseases and heading earliness, and the further crossing of the amphiploid to Triticum aestivum cv Chinese Spring (CS) provided wheat breeeding lines showing additional enhancements for grain size and grain end-use quality. GISH analyses revealed that Dv chromatin introgression occurred in some of them, coupled to chromosome-arm exchanges. Interestingly, three of the selected lines, after two years of genetic analyses and low-input field tests, showed dominance and genetic stability of the adaptive traits. In the second case, the F1s expressed the ‘useful’ Dv genes inherited from the IBLs, providing strong evidence that the Dv genes for trait enhancements are expressed not only in CS but also in ‘elite’ wheat genetic background. The F2 progenies displayed wide segregation offering ample opportunity for selecting the desired combination of the ‘elite’ traits with the traits expressed by the ‘useful’ Dv genes inherited through the IBLs.