Screening and Molecular Identification of Resistance to Powdery Mildew in Pea Germplasm

Pea powdery mildew, caused by Erysiphe pisi, is one of the most important diseases in pea production. The utilization of resistant pea cultivars is the most economical and effective method for controlling the disease. In this study, 396 pea accessions were evaluated for resistance to two powdery mildew isolates from different geographical origins in seedling stage under controlling condition, and four SCAR markers closely linked to pea powdery mildew resistance gene er1 were used to genotype acces- sions with immunity or resistance. The results showed that 101 accessions were immune or resistant to powdery mildew; 59 (14.9%) and 60 (15.2%) accessions were immune to the Beijing isolate and Yunnan isolate, respectively, 54 (13.6%) accessions were immune to both the Beijing isolate and Yunnan isolate. In 82 accessions from China, only eight were immune to both of the two isolates. Thirteen marker genotypes were identified in 66 selected accessions with immunity or resistance through molecular genotyping, and the accessions from the same geographical origin contained different marker genotypes. Eight accessions from Yunnan Province of China shared seven marker genotypes. These results indicated that pea germplasm with resistance to pea powdery mildew has effective and extensive genetic diversity in China.