Identification of Resistance to Soybean Aphids in Early Germplasm

ABSTRACT The soybean aphid (Aphis glycines Matsumura) causes agricultural losses worldwide. Identifying sources of soybean resistance to the soybean aphid is a key strategy in preventing crop damage caused by this pest. Three hundred accessions of cultivated soybean [Glycine max (L.) Merr.] and two hundred accessions of wild soybean (G. soja) originally from northeastern China were evaluated in 2011 and 2012. The objectives of this study were to identify sources and types of resistance to the soybean aphid in early‐maturing soybean germplasm. First, two preliminary choice tests were performed. Accessions that had been identified as aphid resistant in the two choice tests were simultaneously re‐evaluated in a pot choice test, pot no‐choice test, and field no‐choice test to determine the type of resistance. The results of all tests showed that 4 of the 500 accessions were resistant to the soybean aphid. The results of a confirmation test indicated that the logarithmic value and the damage index 25 d after inoculation of accessions ZDD0326, ZDD0219, ZYD00022, and ZYD00033 were significantly (P < 0.05) different from those of susceptible checks in the pot choice test. Accessions ZDD0219, ZYD00022, and ZYD00033 had significantly lower logarithmic values and significantly lower damage index (DI) values than the susceptible checks in the pot and field no‐choice tests (P < 0.05). Evidence indicated that ZDD0219, ZYD00022, and ZYD00033 have antibiotic resistance, and ZDD0326 has antixenosis resistance.