Large-scale evaluation of pea (Pisum sativum L.) germplasm for cold tolerance in the field during winter in Qingdao

As a cool-season crop, pea (Pisum sativum L.) can tolerate frost at the vegetative stage but experiences yield loss when freezing stress occurs at the reproductive stage. Cold-tolerance improvement of pea varieties is important for stable yield and expansion of the winter pea planting area. Under natural low-temperature conditions during winter in Qingdao, Shandong, China, we evaluated the cold tolerance of 3672 pea germplasm accessions in the field and categorized them as displaying high resistance (214), moderate resistance (835), or susceptibility (2623). The highly and moderately resistant genotypes were validated in the following year. We found that genotypes from the winter production region showed higher cold tolerance than genotypes from the spring production region. The accessions identified as having high levels of cold tolerance are recommended as potential genetic resources in cold-tolerance breeding of pea.