Rouf Mian1, Margaret G. Redinbaugh2, and Roy E. Gingery2. (1) The Ohio State University, USDA-ARS, Wooster, OH 44691, (2) USDA-ARS, Department of Plant Pathology, The Ohio State University, 1680 Madison Avenue, Wooster, OH 44691
Seed coat mottling induced by Bean pod mottle virus (BPMV) is a problem for production of high
quality food-grade soybeans in the North Central U.S. In addition to seed coat
mottling, BPMV can reduce soybean yield up to 60%. Although efforts to identify
soybean germplasm with immunity to BPMV have failed, the differential responses
of currently available germplasm to infection with BPMV suggest that partial
resistance to the virus exists. Our long-term objective is to identify and
characterize soybean germplasm with high-level of partial resistance to BPMV To
begin the evaluations, more than 600 soybean accessions grown in six replicates
were rub inoculated with BPMV in a greenhouse, and the development of visual
symptoms on leaves was recorded 7 and 20 d post inoculation using a 1 (no
symptom) to 5 (more than 50% of a leaf covered with symptoms) scale. Large
significant differences were observed in the visual leaf symptoms (from 1.5 to
4.5) among the accessions. The experiment was repeated along with a control
treatment using 24 lines with low symptoms (<2.0) and 24 lines with high
symptoms (>4.0). These 48 lines will be grown in the field in 2006 for evaluation
of inoculated and uninoculated plants for visual
symptoms, seed coat mottling, yield and other related traits. Virus titers on
leaf samples of the inoculated plants will be assessed using quantitative ELISA
and RT-PCR. The results from the greenhouse and field experiments will be
presented. Soybean plants with differential response to infection with BPMV
will be useful in developing soybean cultivars with partial resistance to the
disease.