Chromosomal location of genes for resistance to powdery mildew in Chinese wheat lines Jieyan 94-1-1 and Siyan 94-1-2.

Two Chinese wheat lines Jieyan 94-1-1 and Siyan 94-1-2 are resistant to all 120 isolates of Blumeria graminis f. sp. tritici maintained in Weihenstephan, Germany. Monosomic analyses employing the susceptible set of 21 Chinese Spring monosomic lines revealed that the line Jieyan 94-1-1 carries one dominant gene on translocated wheat/rye chromosome 1B/1R and one recessive gene on chromosome 7B, whereas line Siyan 94-1-2 possesses one recessive gene on chromosome 7B and one dominant gene on chromosome 5D. Allelism tests in combination with the use of specific isolates comfirmed that the dominant genes in Jieyan 94-1-1 and Siyan 94-1-2 are Pm8 and Pm2, respectively. The recessive genes present in each of the two lines are shown to be new alleles located on chromosome 7B at the pm 5 locus. The two genes are tentatively designated mljy in Jieyan 94-1-1 and mlsy in Siyan 94-1-2, respectively.