Molecular and Cytogenetic Identification of Wheat- Thinopyrum intermedium Double Substitution Line-Derived Progenies for Stripe Rust Resistance.

Thinopyrum intermedium (2n = 6x = 42, JJJ S J S StSt) has been hybridized extensively with common wheat and proven to be a valuable germplasm source for improving disease resistance and yield potential of wheat. A novel disease-resistant wheat- Th. intermedium double substitution line X479, carrying 1St(1B) and 4St-4J S (4B), was identified using multi-color non-denaturing fluorescence in situ hybridization (ND-FISH). With the aim of transferring Thinopyrum -specific chromatin to wheat, a total of 573 plants from F 2 and F 3 progenies of X479 crossed with wheat cultivar MY11 were developed and characterized using sequential ND-FISH with multiple probes. Fifteen types of wheat- Thinopyrum translocation chromosomes were preferentially transmitted in the progenies, and the homozygous wheat-1St, and wheat-4J S L translocation lines were identified using ND-FISH, Oligo-FISH painting and CENH3 immunostaining. The wheat-4J S L translocation lines exhibited high levels of resistance to stripe rust prevalent races in field screening. The gene for stripe rust resistance was found to be physically located on FL0-0.60 of the 4J S L, using deletion lines and specific DNA markers. The new wheat- Th. intermedium translocation lines can be exploited as useful germplasms for wheat improvement.