Engineered Durum Wheat Germplasm with Multiple Alien Introgressions: Agronomic and Quality Performance

If genetic gains in wheat yield are to be achieved in today's breeding, increasing the genetic variability of cultivated genotypes is an essential requisite to meet. To this aim, alien gene transfer through chromosome engineering (CE) is a validated and sound strategy. Attempts to incorporate more than one alien segment into cultivated wheat have been rare, particularly for tetraploid durum wheat. Here, we present the agronomic and quality performance of the first successful CE-mediated multiple introgression into the latter species. By assembling into 7AL, 3BS, and 1AS arms of a single genotype homoeologous segments of Thinopyrum ponticum 7el(1)L, Aegilops longissima 3S(l)S, and Triticum aestivum 1DS arms, respectively, we have stacked several valuable alien genes, comprising Lr19+Sr25+Yp (leaf and stem rust resistance and a gene increasing semolina yellowness), Pm13 (powdery mildew resistance), and Gli-D1/Glu-D3 (genes affecting gluten properties), respectively. Advanced progenies of single, double, and triple recombinants were field-tested across three years in a typical durum wheat growing area of central Italy. The results showed that not only all recombinants had normal phenotype and fertility, but also that one of the triple recombinants had the highest yield through all seasons compared with all other recombinants and control cultivars. Moreover, the multiple introgressions enhanced quality traits, including gluten characteristics and semolina yellow index. The presence of effective disease resistance genes confers additional breeding value to the novel and functional CE products, which can greatly contribute to crop security and safety.