Author
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HOBBS, HOUSTON - UNIVERSITY OF ILLINOIS |
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HILL, CURTIS - UNIVERSITY OF ILLINOIS |
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WANG, YI - UNIVERSITY OF ILLINOIS |
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PEDERSEN, WAYNE - UNIVERSITY OF ILLINOIS |
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Domier, Leslie |
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Hartman, Glen |
Submitted to: Plant Disease
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 11/17/2005 Publication Date: 4/1/2006 Citation: Hobbs, H.A., Hill, C.B., Wang, Y., Pedersen, W.L., Domier, L.L., Hartman, G.L. 2006. Green stem disorder of soybean. Plant Disease. 90:513-518. Interpretive Summary: Delayed or incomplete maturation of soybean plants can interfere with soybean seed harvesting especially when large sections of plants in fields mature at different rates. A common manifestation of delayed maturity is termed "green stem." Because the green, tough, and pliable stems of plants with green stem are more difficult for the knives of the combine to cut, ground speed must be slowed while keeping the engine speed high, reducing the fuel efficiency of the combining operation. Two types of field experiments were conducted to test the relationship between green stem and bean pod mottle virus (BPMV) and explore other potential factors that may be involved in the disorder. In one experiment, the percentage of marked plants infected with BPMV in some fields was higher than the incidence of green stem at harvest maturity. Many plants infected with BPMV did not develop green stem, and conversely, many plants that had green stem were not infected with BPMV. Another experiment completed over two growing seasons in field cages showed that green stem developed without BPMV infection. BPMV infection did not increase green stem incidence in comparison to the caged controls. The information provided in this report will be useful for other researchers that are studying green stem and the potential causes of soybean green stem since it provides new information about other biotic factors that are not associated with green stem. Technical Abstract: Green stem is a disorder of soybean characterized by delayed senescence of stems with normal pod ripening and seed maturation. Two types of field experiments were conducted to test the relationship between green stem and bean pod mottle virus (BPMV) and explore other potential factors that may be involved in the disorder. One experiment evaluated green stem and BPMV in collected leaf samples from individual plants in several commercial soybean fields during three growing seasons. Maturing plants (pods with full green seed) and leaf samples were tested by enzyme-linked immunosorbent assay (ELISA) for BPMV. The percentage of marked plants infected with BPMV in some fields was higher than the incidence of green stem at harvest maturity. Many plants infected with BPMV did not develop green stem, and conversely, many plants that had green stem were not infected with BPMV. An analysis of the numbers of plants in four possible classes indicated that green stem disorder was independent of BPMV infection (P = 0.98). Another experiment completed over two growing seasons in field cages showed that green stem developed without BPMV infection. BPMV infection did not increase green stem incidence in comparison to the caged controls. Insect feeding did not have an effect on level of green stem incidence. The exact cause or causes for the green stem disorder remain unknown. |