Performance of soybean with rag1b/rag3 resistance to soybean aphid (Aphis glycines) in potassium-deficient field conditions

In conventional soybean (Glycine max), potassium (K) deficiency is associated with faster time to reproduction and greater nymph production in Aphis glycines (soybean aphid, SBA). Soybean lines with SBA resistance genes are nearing commercialization; it is not known if K deficiency affects them the same way. Eight replicated plantings of the Michigan State University soybean line E06906 with SBA resistance genes rag1b + rag3 were planted in predator-proof cages in a K-deficient field in Montcalm County, Michigan. Four cages were unfertilized, while four were amended with potash. Plants were infested with equal numbers of soybean aphids and populations were monitored weekly through the course of the growing season.