Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/20/2005
Publication Date: 9/23/2005
Citation: Mensah, C., Difonzo, C., Nelson, R.L., Wang, D. 2005. Resistance to soybean aphid in early maturing soybean germplasm. Crop Science. 45:2228-2233. Interpretive Summary: Soybean aphid is a pest of soybean recently introduced into North America. This is the first aphid that has caused economic losses in U.S. soybean production. The only currently used source of resistance is a soybean line adapted to far southern U.S. The objective of this research was to identify new sources of aphid resistance in the USDA Soybean Germplasm Collection in lines adapted to the Midwest U.S. By screening 2,147 germplasm lines from northern China, we identified 4 soybean introductions that are highly resistant to soybean aphid and adapted to the northern U.S. Soybean aphids will not survive if they are forced to feed on these soybean lines. This information will be of interest to soybean breeders who can use these lines to develop resistant cultivars and to entomologists interested in studying mechanisms of resistance.
Technical Abstract: Since 2000 the soybean aphid (Aphis glycines Matsumura) has become a major pest of soybean [Glycine max (L.) Merr.] in the USA. Currently none of the commercial soybean varieties show resistance to the aphid and there are no sources of resistance reported in early maturing soybean germplasm in the USA. The objective of this study was to identify sources of resistance to soybean aphids from early maturing soybean germplasm and to determine the type of resistance they possess. Over a two year period, 2,147 early maturing soybean accessions from maturity group (MG) 0 to III, originally from northern China, were screened for aphid resistance in the greenhouse and in field cages. The plants were hand-inoculated and aphid populations were evaluated 10 days after inoculation. A damage index (0-100%) was calculated for each accession. After two years of screening and confirmation in choice tests, four accessions from Shandong province, PI 567543C, PI 567597C, PI 567541B, and PI 567598B, in MG III were found to be resistant to the soybean aphid. Two of these accessions, PI 567541B and PI 567598B, possessed antibiosis resistance preventing the aphids from reproducing on the plants in a no-choice study. These resistant sources can be used to develop commercial varieties with aphid resistance for the North Central states where soybean varieties of MG 0 to III are cultivated.