Response of secondary selection on soybean cyst nematode reproduction on resistant soybean lines

Soybean cyst nematode, Heterodera glycines Ichinohe, (SCN) populations have been developed which are capable of reproducing on soybean lines known to be resistant to one or more SCN races. Three of the populations developed on PI 88788, PI 90763 and Peking were selected for their differential response on the three hosts. The secondary selection was made on the parent which originally had a high level of resistance. With one exception, secondary selection resulted in increased reproductive ability of the populations on the soybean lines on which they were selected. There was also a corresponding decrease in the reproductive ability on the soybean line on which they were originally developed. The genes from PI 88788, PI 90763 and Peking could be used alternately to provide protection against SCN damage.