|Ziems, A - UNIV. OF NEBRASKA|
|Giesler, L - UNIV. OF NEBRASKA|
|Graef, G - UNIV. OF NEBRASKA|
|Vacha, J - OHIO STATE UNIVERSITY|
|Berry, S - OHIO STATE UNIVERSTIY|
|Madden, L - OHIO STATE UNIVERSITY|
|Dorrance, A - OHIO STATE UNIVERSITY|
Submitted to: Plant Disease
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: December 18, 2006
Publication Date: June 1, 2007
Citation: Ziems, A.D., Giesler, L.J., Graef, G.L., Redinbaugh, M.G., Vacha, J.L., Berry, S.A., Madden, L., Dorrance, A.E. 2007. Response of Soybean Cultivars to Bean pod mottle virus Infection. Plant Disease. 91:719-726. Interpretive Summary: Virus diseases associated with the emergence of two soybean virus vectors, the bean leaf beetle and the soybean aphid, have impacted soybean producers in Ohio and other areas of the north-central soybean growing region over the past few years. Because of the relatively high portion of food grade soybeans grown in the eastern part of the region, concern about increased virus-induced seed mottling is high. However, little was known about the response of Ohio soybean cultivars and germplasm to the emerging viruses. In particular, nothing was known about the effects of early season infection with viruses. Inoculation of field-grown soybeans at the unifoliate stage) with Bean pod mottle virus induced mild mosaic symptoms, leaf puckering and seed mottling. Plant height and yield were reduced. In contrast, plants inoculated at the R6-R7 stage did not show foliar symptoms or height reduction. Early inoculation resulted in a higher percentage of mottled seed and greater yield reduction than did the later inoculation. The results of this study indicate that Bean pod mottle virus infections that occur early in the season can impact producers in an economically important way, and that further research to identify management practices that limit virus spread early in the growing season is needed.
Technical Abstract: Bean pod mottle virus (BPMV) is a new disease of soybeans in Ohio. Increased incidence of seed coat mottling and soybean stems that remain green after pods mature has impacted soybean producers in the past few years. Food grade beans with mottled seed coats cannot be sold at a premium price for tofu production. Bean leaf beetle populations, a known vector of BPMV, have also increased during this same period. The impact of BPMV infection on northern soybean germplasm was studied to determine how early or late inoculation a) produce the greatest levels of mottled seed, b) negatively impacted yield and c) develop green stem syndrome. This information is needed to determine if new management schemes are necessary for BPMV and bean leaf beetle to minimize the economic impact on high value soybeans. Nine soybean cultivars and two breeding lines were evaluated in this field study for foliar and seed symptom development; presence of virus in leaves (or vegetative tissue) and seed coats; and yield following inoculation with bean pod mottle virus at the unifoliate or R7 growth stages. All of the early-inoculated germplasm in this field study expressed virus symptoms including mild mosaic, and seed coat mottling. In addition, there was a reduction in plant height and yield. Enzyme-linked immunosorbent analyses indicated there was virus spread within the plots during the growing season. There were no foliar symptoms or height differences in the plants inoculated at the R6-R7 growth stage although virus was detected in all but one inoculated subplot. In this field study, early inoculations of soybean germplasm resulted in higher percent mottled seed and greater yield reductions than inoculations at R7 when compared to non-inoculated. Symptoms of green stem did not develop under these environmental conditions. These data suggest BPMV infections occurring early in vegetative development produce agronomically important symptoms, and that study of practices to limit virus spread at this growth stage are warranted.