Green Stem Disorder of Soybean

Abstract

Green stem disorder of soybean (Glycine max) is characterized by delayed senescence of stems with normal pod ripening and seed maturation. Three different field research approaches were designed to determine the relationship of green stem disorder to Bean pod mottle virus (BPMV) and other potential factors that may be involved in causing this disorder. The first research approach surveyed green stem disorder and BPMV in individual plants monitored in several commercial soybean fields during three growing seasons. Leaf samples from maturing plants (growth stage R6) were tested by enzyme-linked immunosorbent assay (ELISA) for BPMV. The percentage of monitored plants infected with BPMV at growth stage R6 in some fields was higher than the incidence of green stem disorder at harvest maturity. Many plants infected with BPMV did not develop green stem disorder, and conversely, many plants that had green stem disorder were not infected with BPMV. According to a chi-square test of independence, the data indicated that green stem disorder was independent of BPMV infection at growth stage R6 (P = 0.98). A second research approach compared green stem disorder incidence in an identical set of soybean entries planted in two locations with different levels of natural virus infection. Despite differences in virus infection, including BPMV incidence, 20 of 24 entries had similar green stem disorder incidence at the two locations. A third research approach completed over two growing seasons in field cages showed that green stem disorder developed without BPMV infection. BPMV infection did not increase green stem disorder incidence in comparison to controls. Bean leaf beetle, leaf hopper, or stinkbug feeding did not have an effect on the incidence of green stem disorder. The cause of the green stem disorder remains unknown.

Stability Verification of the Effects of Stem Determination and Earliness of Flowering on Green Stem Disorder of Soybean against Genetic Background and Environment

“…However, these plants occasionally maintain stem greenness, stem moisture and leaf color (green or yellow-green) at seed maturity. Phillips et al (1984) described this phenomenon as "delayed leaf senescence", and Furuya et al (1988) and Hobbs et al (2006) termed this phenomenon as "inharmonious maturation" and "green stem disorder (GSD)", respectively, after unsynchronized senescence between vegetative and reproductive organs. The severity level in plants has been described from entirely green plants to leafless plants with a yellow-green stem.…”

Field Evaluation of Green Stem Disorder in Soybean Cultivars

“…Sometimes petioles may persist on affected plants. Other variations of green stem disorder have been reported but these symptoms are the most commonly observed in the Midwest (Hobbs et al, 2006). Symptoms of green stem disorder may be confused with delayed maturity caused by factors such as virus infection (Sweets and Bailey, 2002), stinkbug feeding [green stink bug Acrosternum hilare (Say), brown stink bugs, Euschistus spp., and the southern green stink bug, Nezara viridula (L.)] (Boethel et al, 2000; Lustosa et al, 1999), fungicide treatments (Padgett et al, 2003), or possibly environmental factors (Malvick, 2001).…”

“…Not all BPMV‐infected plants developed the green stem disorder, and conversely, not all plants that developed green stem were infected with BPMV. Many other possible causes of the green stem disorder have been put forward, including infection by other viruses, insect feeding damage, low soil moisture, potassium deficiency, phytoplasmas, soybean population density, and genetic mutations in soybean plants (Hobbs et al, 2006; Malvick, 2001).…”

“…Although the cause of the green stem disorder is not known, there is evidence of variability among soybean cultivars for green stem disorder incidence (Hobbs et al, 2006; Hill et al, 2003). This variability may be due to differences in cultivar genetics.…”

“…Complaints about the disorder are on the increase in Illinois and in other states (Malvick, 2001). Recent reports indicated that it had become more common in Midwest soybean fields and incidence within fields had increased, often affecting entire fields (Hobbs et al, 2006;Sweets and Bailey, 2002;Wright, 2003). A similar but different problem called "green bean syndrome" occurs in southern states (Boethel et al, 2000;Sweets and Bailey, 2002).…”