Delayed Senescence in Soybean: Terminology, Research Update, and Survey Results from Growers

Abstract

The terms used to describe symptoms of delayed senescence in soybean often are used inconsistently or interchangeably and do not adequately distinguish the observed symptoms in the field. Various causes have been proposed to explain the development of delayed senescence symptoms. In this article, we review published reports on delayed senescence symptoms in soybean, summarize current research findings, provide examples of terms related to specific symptoms, and present an overview of the results of a multi-state survey directed to soybean growers to understand their concerns about delayed soybean senescence. Some of these terms, such as green bean syndrome and green stem syndrome, describe symptoms induced by biotic factors, while other terms describe symptoms associated with abiotic factors. Some delayed senescence terms involve the whole plant remaining green while other terms include just the stem and other plant parts such as pods. In the grower survey, 77% reported observing soybean plants or plant parts that remained green after most plants in the field were fully mature with ripe seed. Most respondents attributed these symptoms to changes in breeding and choice of cultivars. At the end of this article, we standardized the terms used to describe delayed senescence in soybean. RightsWorks produced by employees of the U.S. Government as part of their official duties are not copyrighted within the U.S. The content of this document is not copyrighted.

Effect of thinning and shade removal on green stem disorder in soybean

“…per node and total node number tended to be higher in the group the shade of which was removed at R1 than that at R5 stage. Harbach et al (2016) reported that in soybean, delayed senescence symptoms, including GSD, are manifested through various combinations of delayed maturation of the stem, leaves, and pods, but these symptoms have not been adequately distinguished from each other. In the current study, GSD was primarily evaluated using the GSD score, which was based on the color of the stem and the ratio of existing leaves at R8 stage (when almost all pods have matured), as in previous studies (Fujii et al, 2015;Furuya & Umezaki 1993;Isobe et al, 2015;Mochizuki et al, 2005;Takehara et al, 2016;Tsujimoto et al, 2006;Yamada et al, 2014).…”

“…Typically, as soybean pods mature and reach harvesting stage, the leaves turn yellow and drop, and the green stem turns pale and loses moisture. Green stem disorder (GSD) in soybean is defined as the condition in which the stems and leaves stay green and retain some moisture even when the pods normally mature (Harbach et al, 2016;Hobbs et al, 2006). GSD has also been termed delayed leaf senescence (Phillips et al, 1984) and inharmonious maturation (Furuya et al, 1988).…”

“…GSD often negatively affects harvesting and seed appearance. Harvest efficiency is greatly reduced compared to normally matured soybean plants because it is difficult to cut the moist stems of GSD soybeans by using combine harvesters (Harbach et al, 2016;Hill et al, 2006). Seed appearance is also impaired because the seed surface is stained with the sap of moist stems and leaves in combine harvesters (Ogiwara, 2002).…”

Comparison of equipment for grain sampling

“…It should also be emphasized that the causes associated with the presence of green pods in soybean grains are diverse (Silva et al, 2013;Harbach et al, 2016), for instance, the type of plant growth (Boudreaux & Griffin, 2011). Moreover, green pods during harvest can be threshed by the threshing mechanisms of the harvester, culminating in the release of immature grains in the harvested mass (Sinnecker, 2005).…”

The Senescence (Stay-Green)—An Important Trait to Exploit Crop Residuals for Bioenergy

“…The relationship of senescence and agronomic traits in oil crops is similar to other crops, increasing both the yield but also the moisture. In this aspect, complications in the harvesting operations and a reduction in the quality of the grain due to a delayed senescence have being described in soybean [92].…”