Molecular Cytogenetic Identification of a Novel Wheat- 1J (1B) Substitution Line Resistant to Powdery Mildew and Leaf Rust.

(2 = 10 = 70) is a wild relative of wheat with high tolerance to both biotic and abiotic stresses; it has been wildly used in wheat genetic improvement. A disomic substitution line named SN19647 was derived from a cross between and the wheat- partial amphiploid SNTE20 (2 = 8 = 56). It was evaluated for disease resistance and characterized sequential fluorescence hybridization (FISH)-genomic hybridization (GISH) and molecular markers. The results showed that SN19647 carried resistance to both powdery mildew and leaf rust. It contained 42 chromosomes with a pair of wheat chromosome 1B replaced by a pair of J chromosomes from . In addition to chromosomal substitution events, structural variation also occurred on wheat chromosomes 2A, 5A, 6B, and 7B. Based on marker analysis, 19 markers specific to the J chromosome were obtained, of which seventeen markers belonged to homoeologous group one. These results indicated that SN19647 was a 1J (1B) substitution line. Compared with the known 1J (1D) substitution line CH10A5, it was found that 17 markers generated different specific bands to , confirming the novelty of the 1J chromosome in SN19647. Therefore, SN19647, resistant to powdery mildew and leaf rust, was a novel 1J (1B) substitution line that can be used in wheat genetic improvement.