Can We Predict Green Stem Disorder?
Sustainable Production
DiseaseField management Pest
Parent Project:
This is the first year of this project.
Lead Principal Investigator:
Seth Naeve, University of Minnesota
Co-Principal Investigators:
Project Code:
Contributing Organization (Checkoff):
Institution Funded:
Brief Project Summary:
Green stem disorder can result from different soybean stressors across the country, but specific causes remain unclear. This research project focuses on understanding the sensitivity of soybean stress and when those stressors may trigger green stem disorder. Researchers are looking at reduced sunlight and drought stressors and when they could activate green stem disorder in northern states. The team hopes to find connections between stress timing and onset of the disorder as well as how severe green stem disorder becomes under these particular stressors. Knowing how and when green stem disorder is triggered could reduce its occurrence.
Key Beneficiaries:
#agronomists, #Extension crop specialists, #farmers
Unique Keywords:
#agronomy, #green stem disorder, #soybean diseases, #stress
Information And Results
Project Summary

Green stem is a disorder of soybean in which stems remain green and moist well past the point when pods and seeds are fully ripe and dry. Various names are used to describe the problem including green soybean syndrome and greening effect. Green stem disorder complicates harvesting by significantly increasing the difficulty in cutting and threshing affected plants during harvest. As a result, combine operators often must reduce ground speed and increase engine power, resulting in poor fuel efficiency and increased harvest time. Harvest delays also increase the chances of lodging, shattering, and seed decay that can reduce grain yield and/or quality.

The cause of green stem disorder is uncertain but it can be the result of several different potential factors. Specific causes of green stem syndrome vary from year to year and location to location, but are frequently associated with plant stress during pod and seed development (Holshouser, 2009). A common characteristic of plants exhibiting green stem disorder is that they have significantly fewer pods. Research at the University of Kentucky clearly established this relationship of increasing green stem disorder with a reduction in pod number. When a pod-aborting or seed-aborting stress is brief and most leaves remain intact, the inability of the crop to use any excess photosynthates can lead to green stem disorder. Therefore, a brief but significant period of stress during the reproductive stages can greatly alter the source:sink ratio in soybean and lead to green stem syndrome.

Previous experiments explored the impact of different depodding levels; however, there have been no attempts to identify the most sensitive period for green stem disorder expression. A better understanding of the effect of stress timing on the expression of this disorder would be useful to predict the occurrence and severity before its expression at harvest maturity. This would be helpful for harvest logistics and efficiency. The question we want to answer is: Can we connect stress timing with green stem disorder incidence and severity? Additionally, since the ultimate cause of green stem syndrome is thought to be reduced pod and/or seed-set, the ultimate goal of this research is to attempt to correct or minimize these yield-reducing factors to increase yields while reducing green stem syndrome.

Project Objectives

(1) Identify the most sensitive stages at which crop stress leads to green stem syndrome.
(2) Assess relationships between green stem disorder and grain yield.

Project Deliverables

(1) Identify the most critical phenological stage(s) for triggering green stem disorder.
(2) Quantify the relationship between green stem incidence and yield.
(3) Identify potential targets for soybean management or breeding to reduce losses due to these stresses and green stem syndrome.

Progress Of Work

Updated November 30, 2023:
? We conducted a controlled field experiment at St. Paul.
? Samples were processed and data was analyzed
? We were able to establish an association between stress and green stem syndrome.
? We were able to identify differential sensitivity according to the moment of the stress during the cycle.

View uploaded report PDF file

Final Project Results

Benefit To Soybean Farmers

(1) This project will allow us to identify critical periods when crop stress leads to green stem disorder.
(2) The information generated would help farmers predict and anticipate green stem disorder events based on crop conditions during critical crops stages, even before this disorder is noticeable.
(3) It will help farmers take actions that could help increase harvest efficiency.
(4) We may identify potential targets for soybean management or breeding to reduce losses due to these stresses and green stem syndrome.

The United Soybean Research Retention policy will display final reports with the project once completed but working files will be purged after three years. And financial information after seven years. All pertinent information is in the final report or if you want more information, please contact the project lead at your state soybean organization or principal investigator listed on the project.