Geographic structure and human‐mediated gene flow in driving genetic diversity of Heterodera glycines : A mitochondrial COI ‐based cross‐regional analysis

Abstract BACKGROUND The soybean cyst nematode (SCN, Heterodera glycines ) is a major threat to Chinese soybean production. Understanding its spatial distribution and genetic dynamics is critical for developing sustainable management strategies. RESULTS Our survey confirmed SCN presence in 15 of 19 sampled provinces, with high‐density populations in Xinjiang and Inner Mongolia indicating expansion risks. Analysis of the mitochondrial COI gene of 44 Chinese populations revealed three distinct genetic groups: Northeast China, Huang‐Huai‐Hai region and Northwest China. This regional structure aligns with major soybean cultivation zones and host adaptation. Huang‐Huai‐Hai populations showed genetic homogeneity (centered on Hap3/Hap11) linked to uniform cultivation and Race 2 dominance. Northeast populations exhibited high heterogeneity owing to diversified physiological Races under selection from resistant varieties. Crucially, significant human‐mediated gene flow ( N m = 4.25) from the United States to Northeast China was detected, suggesting SCN reintroduction via imported soybeans. Within China, bidirectional gene flow connected Northeast and Huang‐Huai‐Hai regions via agricultural connectivity, whereas the Northwest remained isolated. CONCLUSION These findings demonstrate that contemporary agricultural trade and practices drive SCN genetic architecture and dispersal more powerfully than geography, underpinning the need for region‐specific management strategies that include careful monitoring and quarantine of imported crops. © 2026 Society of Chemical Industry.