Molecular characterization of a wheat -<Emphasis Type="Italic">Thinopyrum ponticum</Emphasis> partial amphiploid and its derived substitution line for resistance to stripe rust

Stripe rust (caused by Puccinia striiformis) occurs annually in most wheat-growing areas of the world. Thinopyrum ponticum has provided novel rust resistance genes to protect wheat from this fungal disease. Wheat – Th. ponticum partial amphiploid line 7430 and a substitution line X005 developed from crosses between wheat and 7430 were resistant to stripe rust isolates from China. Genomic in situ hybridization (GISH) analysis using Pseudoroegneria spicata genomic DNA as a probe demonstrated that the partial amphiploid line 7430 contained ten J^s and six J genome chromosomes, and line X005 had a pair of J^s-chromosomes. Giemsa-C banding further revealed that both lines 7430 and X005 were absent of wheat chromosomes 6B. The EST based PCR confirmed that the introduced J^s chromosomes belonging to linkage group 6, indicating that line X005 was a 6J^s/6B substitution line. Both resistance observation and sequence characterized amplified region (SCAR) markers displayed that the introduced chromosomes 6J^s were responsible for the stripe rust resistances. Therefore, lines 7430 and X005 can be used as a donor in wheat breeding for stripe rust resistance.