Regional Distribution, Virulence Phenotype Identification and Resistant Cultivar Deployment Strategy of Soybean Cyst Nematode in China

Soybean cyst nematode (SCN, Heterodera glycines Ichinohe) is the most destructive soil-borne pathogen of soybean worldwide. This study elucidated the distribution, population density dynamics, virulence diversity, and economic impact of SCN across China, with systematic monitoring in Inner Mongolia and Anhui in 2025. Among 1,792 soil samples collected from 31 provinces (2015–2025), 58.71% tested positive across 22 provinces, and annual economic losses were estimated at >2.5 billion Chinese renminbi (ca US $375 million) at a conservative 5% yield loss rate. Virulence phenotyping identified five races (1, 2, 3, 4, 6) and six HG Types (HG 0, 2.5, 2.5.7, 1.2.5.7, 4.5, 1.2.3.5.7). Anhui exhibited the highest complexity with all six HG Types, while Inner Mongolia was dominated by HG 0, though the highly virulent HG 1.2.3.5.7 reached ~40% frequency in Hulunbuir. Genotyping of 60 commercial cultivars for rhg1 and Rhg4 copy numbers identified resistance categories, highlighting risks of sole reliance on PI88788-type resistance. A region-specific deployment strategy is recommended: high-copy rhg1-b cultivars for HG Type 0-dominated regions, and rhg1-a + Rhg4-a combination cultivars for regions with complex virulence profiles, thereby prolonging resistance durability. This study fills systematic monitoring gaps and provides a scientific basis for region-specific SCN management and resistance source rotation in China.