Developing stripe rust resistant wheat (Triticum aestivum L.) lines with gene pyramiding strategy and marker-assisted selection

Stripe rust or yellow rust, caused by Puccinia striiformis f. sp. tritici (Pst), is one of the most destructive diseases of wheat (Triticum aestivum L.) worldwide. Growing resistant cultivars is the most effective approach to control the disease. There have been numerous reports on the resistance genes to stripe rust (Yr gene) in wheat, but just a few Yr genes are resistant to currently epidemic races and applied in wheat production. Gene pyramiding is considered to be an effective way to enhance durable disease resistance in crops. In this experiment, a panel of Yr gene pyramiding lines (consisting of 3–8 Yr genes) with cv. Chuanyu12 as background parent were constructed by using marker assistant selection and evaluated under currently epidemic Pst races. The results showed that the number of pyramided Yr genes was significant correlated with stripe rust resistance (p < 0.001). Yr15, Yr62 and Yr65 are effective to the current Pst races. Pyramiding more than four effective or partially effective Yr genes can provide enough resistance to stripe rust. And additive effects or epistatic effects existed in gene combinations in this study, such as Yr26 + Yr48, Yr30 + Yr64 and Yr30 + Yr48 et al. Moreover, the effects of Yr gene pyramids on currently prevalent Pst races and agronomic traits were also evaluated, and Yr-gene pyramiding lines with desirable agronomic traits were obtained for durable controlling Pst in wheat breeding.