Delayed senescence in soybean: Terminology, research update, and survey results from growers

Authors: HARBACH, CHELSEA - University Of Illinois; ALLEN, TOM - Mississippi State University; Bowen, Charles; DAVIS, JAMES - Louisiana State University Agcenter; HILL, CURTIS - University Of Illinois; LEITMAN, MARK - United Soybean Board; LEONARD, B - Louisiana State University Agcenter; MUELLER, D - Iowa State University; PADGETT, G - Louisiana State University Agcenter; PHILLIPS, XAVIER - Iowa State University; SCHNEIDER, R - Louisiana State University Agcenter; SIKORA, E - Alabama Cooperative Extension Service; SINGH, A - Iowa State University; Hartman, Glen

Submitted to: Plant Health Progress
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/23/2016
Publication Date: 4/15/2016
Citation: Harbach, C.J., Allen, T.W., Bowen, C.R., Davis, J.A., Hill, C.B., Leitman, M., Leonard, B.R., Mueller, D.S., Padgett, G.B., Phillips, X.A., Schneider, R.W., Sikora, E.J., Singh, A.K., Hartman, G.L. 2016. Delayed senescence in soybean: Terminology, research update, and survey results from growers. Plant Health Progress. 17:76-83.

Interpretive Summary: Terms used to describe symptoms associated with the delayed senescence of stems, leaves, pods, and seeds or various combinations of affected organs in field-grown soybean include delayed stem senescence, green bean syndrome, green plant malady, green stem, green stem disorder, green stem malady, green stem syndrome, greening effect, and stay green. In general, these terms often do not adequately describe the associated symptoms. As a result, scientific articles and agriculture press releases often use various terms inconsistently or interchangeably to describe delayed senescence in soybean. 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 senescence. We propose to unify terms describing delayed senescence based on which plant parts that remain green. In general, more research, including the physiological and biochemical mechanisms, is needed to fully understand these various delayed maturity maladies to aid in development of soybean cultivars insensitive to delayed senescence. This information will be used by soybean researchers and extension personnel that are interested in soybean production.

Technical 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 senescence. Some of these terms, such as green bean syndrome and green stem syndrome, can be induced by biotic factors while others, including green stem disorder and stay-green, may be related to background genetics of the soybean cultivar. Some delayed senescence terms involve the whole plant remaining green while other terms include just the stem and/or pods remaining green. In a survey of growers and crop advisors, 77% reported observing soybean plants or plant parts that remained green beyond when most plants in the field were fully mature with ripe seed. Most respondents attributed these symptoms to changes in breeding and choice of cultivars. We propose to unify terms describing delayed senescence based on which plant parts that remain green and the duration of these symptoms.