Pyramiding different alien chromosome segments in durum wheat: Feasibility and breeding potential

Abstract

Wheat chromosome engineering, i.e., the transfer of alien chromosome segments from various Triticeae species into cultivated wheats, is greatly benefiting from the recent advancements in molecular genetics, cytogenetics, and genomics. Powerful tools are currently available that make selection of desired genotypes far more pre- cise and effective than in the past, thus giving this transfer strategy considerable po- tential for meaningful practical achievements. Such tools were successfully applied to engineer the durum wheat genome with small alien segments containing genes for disease resistance and quality traits, including Lr19 (leaf rust resistance) and Yp (yellow endosperm pigmentation) from Thinopyrumponticum, Pm13 (powdery mildew resistance) from Aegilops longissima, and the Glu-D3 and Glu-D1 glutenin subunit genes from Triticumaestivum. Targeted segments with such genes, all being of minimal size, were first separately incorporated into durum wheat by ph1-induced homoeologous recombination. The positive performance of selected recombinant lines from each transfer project encouraged attempts to develop multiple alien seg- ment combinations. The results obtained with double and also triple recombinants indicate a good tolerance of the durum wheat genome even toward such complex manipulations, which thus appear to offer good prospects for simultaneously enrich- ing durum wheat germplasm with several valuable traits from related Triticeae.