Abstract:Stripe rust caused by Puccinia striiformis f.sp.tritici (Pst) is an important worldwide wheat disease. CH223 is a wheat multi-resistance line developed recently from crossing susceptible wheat cultivars with Thinopyrum intermedium-derived resistant partial amphiploid TAI7047 as donor parents. In this study, the evaluation of resistance reactions demonstrated that CH223 and its donor TAI7047 as well as the wild parents were resistant at the seedling and adult stages to CYR32, the most widely virulent in China, and three other prevalent Pst races, whereas the wheat parents of CH223 and TAI7047 were susceptible, indicating that the stripe rust resistance in CH223 was possibly derived from Th.intermedium. Genetic analysis of the F1, F2, F2:3 and BC1 populations from stripe rust resistant line CH223 revealed that a single dominant gene was responsible for the adult resistance to CYR32. The cytological observation demonstrated that the somatic chromosome number of CH223 and its F1 hybrids involving Chinese Spring wheat was 2n=42, and their most pollen mother cell had a regular pairing of 2n=21Ⅱ at meiosis, suggesting that this resistant line was cytologically a stable cryptic alien introgression, and its chromosome constitution largely identical to that of wheat.