Mining of Wheat Alleles for Goal-Oriented Marker-Assisted Breeding.

Powdery mildew of wheat, caused by f. sp. (), is a devastating disease that seriously reduces yield and quality worldwide. Utilization of plant resistance genes is an attractive and effective strategy for controlling this disease. Among the reported powdery mildew () resistance genes, exhibits a diverse resistance spectrum among its multiple alleles. It has been widely used in China for resistance breeding for powdery mildew. To mine more alleles and clarify their distribution, we screened 33 wheat cultivars/breeding lines carrying alleles from 641 wheat genotypes using diagnostic and -linked markers. To further investigate the relationships within the alleles, we compared their resistance spectra, polymorphism of marker alleles and gene sequences, and found that they have identical marker alleles and gene sequences but diverse resistance spectra. In addition, the diagnostic kompetitive allele-specific PCR (KASP) marker, , was developed and was shown to detect all the alleles in the different genetic backgrounds. These findings provide valuable information for the distribution and rational use of alleles, push forward their marker-assisted breeding (MAS), and hence improve the control of wheat powdery mildew.