Wheat leaf rust resistance conferred by the terminal region of Thinopyrum intermedium chromosome 7JsS

Abstract

Abstract Partial amphiploid Xiaoyan 78829 contains 14 Thinopyrum intermedium chromosomes and exhibits excellent resistance to fungal disease. To transfer this resistance to common wheat, a translocation line WTT26 was developed by pollen irradiation. Disease evaluation showed that WTT26 was nearly immune to 14 common races of Puccinia triticina, highly resistant to P. graminis f. sp. tritici Ug99 race PTKST at the seedling stage as well as to Blumeria graminis f. sp. tritici under field conditions at the adult plant stage. Cytogenetic identification, single nucleotide polymorphism array analysis and Th. intermedium-specific marker amplification, revealed that WTT26 carries the T4BS·7JsS translocation. Novel translocation lines with desirable yield characters and excellent leaf rust resistance was developed using irradiation. A total of 124 specific markers were developed using specific-locus amplified fragment sequencing to further enrich the marker information of chromosome 7JsS. Furthermore, a refined physical map of chromosome 7JsS that contains 74 specific markers was constructed with its dissection into six physical regions. Combining data from specific marker amplification and resistance evaluation resulted in a new leaf rust resistance locus mapped in the 0–69.29 Mb region on chromosome 7JsS. These new developed translocation lines and markers will contribute to wheat breeding for disease resistance.