Mapping of a Recessive Gene for All-Stage Resistance to Stripe Rust in a Wheat Line Derived from Cultivated Einkorn ( Triticum monococcum ).

Stripe rust, caused by Puccinia striiformis f. sp. tritici ( Pst ), is one of the most destructive fungal diseases of wheat. Cultivated einkorn ( Triticum monococcum L. ssp. monococcum , 2 n = 2 x = 14, A m A m ), one of the founder crops of agriculture, harbors unexploited genetic sources for wheat improvement. An advanced wheat line, Z15-1949, with 42 chromosomes, selected from the hybrids of Pst -susceptible common wheat cultivar Crocus and resistant T. monococcum accession 10-1, exhibits high resistance to a mixture of the prevalent Chinese Pst races. Genetic analysis on F 1 , F 2 , and F 2:3 generations of the cross between Z15-1949 and Pst -susceptible common wheat SY95-71 indicated that the resistance of Z15-1949 was conferred by a recessive gene, tentatively designated as YrZ15-1949 . This gene was mapped to the short arm of chromosome 7D using the Wheat 55K single nucleotide polymorphism array, flanked by markers KASP-1949-2 and KASP-1949-10 within a 3.3-cM genetic interval corresponding to a 1.12-Mb physical region in the Chinese Spring reference genome V2.0. The gene differs from previously reported Yr genes on 7D based on their physical positions and is probably a novel gene. YrZ15-1949 would be a valuable resource for developing Pst -resistant wheat cultivars, and the linked markers could be used for marker-assisted selection.