BROWN STEM ROT RESISTANCE IN SOYBEAN GERM PLASM FROM CENTRAL CHINA

Soybean accessions from China were screened in an attempt to identify unique sources of resistance to Phialophora gregata, the cause of brow n stem rot. In 1994, over 500 accessions from the USDA Soybean Germpla sm Collection, University of Illinois, Urbana-Champaign, were evaluate d in the field at Urbana, IL, for reaction to brown stem rot. The acce ssions originated from nine provinces in central China and ranged in m aturity from groups II to IV. Disease assessment was based on incidenc e of foliar symptoms and severity of stem symptoms produced by infecti on with natural inoculum. Based on field results, 64 putatively resist ant lines were selected and evaluated in the greenhouse by a root-dip inoculation method. Thirteen accessions with levels of resistance equa l to those of resistant standards were identified from five provinces. These lines may have value as donors of unique sources of resistance to brown stem rot.