Screening for Pea Germplasms Resistant to Fusarium Wilt Race 5

Abstract

Fusarium wilt (FW), caused by Fusarium oxysporum f. sp. pisi (Fop), has always been an important disease affecting pea production and causing severe yield losses in most pea-growing areas worldwide. Growing resistant pea cultivars is the most economical and effective method for controlling the disease. In this study, firstly, 21 Fusarium oxysporum isolates were identified as races 1 and 5 of Fop based on morphological and molecular characteristics, and the disease reactions of seven pea differential cultivars. Then, a detailed resistance evaluation strategy was established and validated by a death rate score, disease index, and percentage of leaves showing symptoms for each individual plant. Finally, a 1311 pea germplasm collection including 740 accessions from China and 571 accessions aboard or unknown sources was evaluated for resistance to a representative isolate PF22b of Fop race 5, and the results showed that 28 accessions and 164 accessions were highly resistant (HR) and resistant (R), respectively. Among these resistance accessions, 13 HR and 44 R accessions were collected from 19 provinces in China, most of which came from Sichuan, Tibet, and Gansu Provinces. The 15 HR and 120 R accessions were collected in 10 countries outside China or unknown sources, the majority of which came from the United States, Australia, and Russia. The findings would provide important information for using resistance pea cultivars to control Fusarium wilt. Incorporating these resistance accessions into breeding programs will contribute to improving the Fop resistance of pea cultivars.