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

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: = 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.