bean pests including the soybean looper (Pseudoplusia includens Walker) (All et al., 1989). In more than 25 yr since the discovery of soybean [Glycine max There are several reasons for the difficulty experi(L.) Merr.] resistance to defoliating insects, attempts to introgress enced in breeding for PRI in soybean. Resistant germthis trait into elite germplasm have been relatively unsuccessful. Re...

Recent work defines coevolution between plants and herbivores as pairwise when the pattern of selection on resistance traits and the response to selection are both independent of the presence or absence of other herbivores. In addition, for a pairwise response to selection, resistance to a focal herbivore must have the same genetic basis in the presence and absence of other herbivores. None of ...