Association of green stem disorder with agronomic traits in soybean

Green stem disorder (GSD) of soybean [Glycine max (L.) Merr.] is the occurrence of non-senescent, fleshy green stems of plants with normal, fully mature pods and seeds. The main focus of this study was to determine the relationship between GSD incidence and agronomic traits and to determine if GSD incidence was associated with soybean cultivars, years, location of trials, and rainfall. Data on GSD incidence based on a percentage of plants in plots showing symptoms were collected for soybean cultivars in 86 trials from 2009 to 2012 at seven locations in Illinois. The incidence of GSD ranged from 0% (three trials) to 88% with a mean incidence of 12% averaged over the 83 trials. The GSD incidence was correlated with data on yield, plant height and lodging, and seed moisture, protein, and oil content for all trials. The incidence of GSD was positively correlated (P < 0.05) with yield (12 cases), plant height (24) and lodging (29), and seed moisture (35), protein (19), and oil content (2), and negatively correlated (P < 0.05) with yield (eight cases), plant height (2) and lodging (3), and seed moisture (1), protein (3), and oil content (24). Correlations among agronomic traits, GSD, and in-season precipitation, indicated that yield and precipitation (May, June, and July) were negatively correlated (P < 0.05) with GSD. The incidence of GSD is a result of the genetics of soybean cultivars and how they interact with the environment.