Resistance to Aphis glycines Matsumura during the reproductive stages of soybeans

The soybean aphid, Aphis glycines, is a recently introduced pest that represents a growing risk to soybean production throughout the Midwest. One solution to this problem is the use of host plant resistance, which is a common tactic for managing aphids. The objectives of this study were to evaluate selected soybean genotypes in the reproductive stage for resistance to Aphis glycines under greenhouse and field conditions, document the categories of resistance among the aphid-resistant soybeans, and investigate changes in carbon exchange rates and peroxidase activity between resistant and susceptible soybean in response to aphid injury. Field and greenhouse studies identified KS4202, K1621, and K-1639-2 as moderately to highly resistant. No-choice studies are currently underway to characterize the relative levels of antibiosis and tolerance among the resistant genotypes. Number of aphids and rate of development were used to quantify the level of antibiosis, while the level of tolerance was determined by comparing yield parameters and gas exchange responses between aphid-infested and control plants of the resistant genotypes. Results from these studies will be presented at the 2008 ESA Annual Meeting.