New sources of soybean resistance against soybean aphid (Aphis glycines) biotypes

Soybean aphids, Aphis glycines Matsumura, is one of the most important insect pest of soybean [Glycine max (L.) Merr.], in the northern production region of North American. Four soybean aphid biotypes have been identified since its introduction in 2000. The discovery of new aphid biotypes provides the impetus to search for new sources of aphid resistance. In this research, five early-maturing PI accessions (PI567541B, PI567543C, PI567597C, PI567598B, PI605765B), and six additional PI accessions (PI 437696, PI 587663, PI 587677, PI 587685, PI 587972, PI 594592) that were previously found resistant to soybean aphid biotypes 1, 2, or 3, breeding lines with known aphid resistance, and susceptible public cultivars, were tested against soybean aphid biotype 4 in choice and non-choice tests. The results showed that all five early-maturing PI accessions were as susceptible as Williams 82 to biotype 4. In contrast, the six PI accessions were resistant to biotype 4. These multi-biotype-resistant sources will be useful in developing soybean cultivars with increased resistance to soybean aphids.