Eight soybean cyst nematode, Heterodera glycines Ichinohe, cultures were developed by their continuous selection on soybean lines with various level of resistance. Each soybean line was inoculated with eggs and larvae of the eight cultures. Female development was much higher on 'Essex' and 'Forrest' than the other lines. The development of nematode cultures selected on Essex and Forrest was low on the other six soybean lines compared with the lines on which they were selected. PI 89772 and PI 90763 had a high level of resistance to the culture selected on PI 88788, whereas cultures selected on PI 89772 and PI 90763 reproduced very little on PI 88788 and PI 209352. Cultures selected on PI 87631-1, PI 209332, and 'Cloud' gave response similar to that of PI 88788. The use of various sources for resistant variety development program is discussed.
Keywords: Glycine max L.; races; resistance.