Wednesday, November 15, 2006

Soybean Genotypes Show Differential Responses to Inoculation with Bean Pod Mottle Virus.

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.