Soybean Quality vs Yield
A preface should accompany this post: soybean yields [in the absence of SDS] have been tremendous, thanks in part by a growing season that provided ample amounts of rain and seasonal temperatures that extended grain fill to the very end of physiological maturity.
We’ve been getting field calls from growers noticing variable soybean seed quality. While adequate moisture increases the likelihood for elevated yields, it can also increase the likelihood of diseases in our soybean crop. What we are seeing is PHOMOPSIS SEED DECAY. Phomopsis is caused by a pathogen in the Diaporthe genus, the same causal organism as POD and STEM BLIGHT. Infection occurs when spores splash from field residue onto the plant/pod; in some cases, weeds present in the field host the disease. The disease reduces quality and can also reduce yield, especially if seeds are aborted. If you find this disease in your field, harvest as soon as possible. Cool and wet conditions will continue disease development into harvest.
While genetics do vary in susceptibility, the issue is likely not prevalent enough to select varieties for this criteria alone. Tillage and rotation may help to reduce the amount of inoculum for infection in subsequent cropping years.
For more information, check out this article from Crop Protection Network: http://cropprotectionnetwork.org/wp-content/uploads/2016/03/CPN-1007-Pod-and-stem-blight-and-phomopsis-seed-decay-2.0.pdf