Soybeans: Seed Quality Issues In 2018 – Unraveling A Critical Issue

Purple seed staining of soybean in south central Nebraska. Photo: Jennifer Rees, UNL CropWatch

By now, most soybean producers have either first-hand or second-hand knowledge of the issues associated with poor quality of harvested soybean seed in 2018. This year, the problem seems to be affecting producers in soybean-producing regions throughout much of the US. See excerpts from the below linked articles.

  • Soybean Seed Quality Moving Backwards in the Field (Oct. 8, 2018 KyGrains.info) by Carl Bradley and Chad Lee with the University of Kentucky. From this article come the following excerpts. “The excessive rains of September and early October are more than many soybean plants can handle…The wet weather provided the perfect conditions for various fungi to take advantage of these plants…Farmers can expect lower yields and damaged seed. Damaged seed is likely to receive discounted prices from grain buyers…The wet weather this summer was a blessing to crop growth and higher yields. The wet weather at soybean maturity was a curse to seed quality and yields.”
  • Phomopsis Seed Decay and Purple Seed Stain Prevalent in Harvested Soybeans (Oct. 25, 2018 KyGrains.info) by Carl Bradley with the University of Kentucky. “Although soybean yields have been pretty good this year, the seed quality of harvested soybeans has not been great in some areas of the state. Seed diseases have been prevalent in areas that have received a lot of rain since harvest season began. Phomopsis seed decay (usually caused by Diaporthe longicolla) and purple seed stain (caused by Cercospora kikuchii) are the two main culprits of poor quality seed.”
  • Crop Quality Hurt by Rains (Oct. 8, 2018 ICM News) by Charles Hurburgh and Alison Robertson with Iowa State University. “Rains followed by above average temperatures began over Labor Day weekend, and have been repeated nearly every weekend to date…The 2018 crop is now at a point where the wet conditions are affecting quality…If the soak-dry cycles continue with more heavy rain, expect pod splitting and eventually grey colored beans.”
  • Managing Wet Soybeans in a Late Harvest (Oct. 18, 2018 ICM News) by Charles Hurburgh and Meaghan Anderson with Iowa State University. “As of Oct. 14, 2018, Iowa soybean harvest was only about 20% complete, making it the latest soybean harvest on record. This was caused by the prolonged heavy rains in September and early October. As a result, field losses, abnormally high harvest moisture content, and moldy/weathered soybeans are all issues this year…In-field quality has decreased, harvest losses have increased, and high moisture beans present both a handling and marketing challenge.”
  • Seed Quality Issues in Soybean (Oct. 2018 C.O.R.N. Newsletter) by Anne Dorrance with The Ohio State University. “Let’s face it–we’ve had historic rains in part of Ohio during 2018 and we are now observing many late season issues that come with this. Seed quality is one of them and the symptoms or warning signs that there could be issues are on the stems. The stems in some fields are heavily colonized with a mix of disease pathogens that cause Anthracnose, Cersospora, and pod and stem blight.”
  • Soybean Harvest Losses Continue to Mount in Upper Midwest (Oct. 17, 2018 DTN) by Mary Kennedy. “Most of the crop was looking good heading into September, but then came more rain, and more rain on top of that. Because of all the rain that delayed harvest, soybeans started to shatter.” One producer said “This sounds like it is a really big problem across a lot of Iowa. I am guessing we will see losses from 10% to 50%. It depends on the field and variety… Also seeing what looks like mold on some beans when I break them open and many black beans that have rotted.” From another producer “…I’m sure we will be dealing with quality issues too. Because of this, the elevators will be taking discounts for damage, which will further add to loss in the final price.”
  • Soybean Damage Widespread: Crop Insurance, Blend Limits, Salvage Market (Oct. 25, 2018 DTN) by Katie Dehlinger. “Shattered, sprouted and discolored soybeans are a common sight in parts of Kansas, Iowa and the Mississippi Delta that have been pelted with persistent, heavy rains this harvest season…And in the Mississippi Delta, the high levels of damage are so widespread it’s creating a situation long-time crop insurance agents have never seen before: Farmers are being forced into selling into salvage markets without meeting RMA’s reduction in value criteria.”
  • Dealing with Soybean Seed Quality Issues (Oct. 9, 2018 UTcrops News blog) by Angela McClure with the University of Tenn. “With the extended wet weather in late September, growers in many parts of the southeast are dealing with varying degrees of seed quality issues in soybean…. In Tennessee, at greater risk are fields that were mature at the onset of the rainy weather, and received rain in the double digits over several days…. Early applications of fungicide (R1-R3) were likely not able to protect from very late-season diseases that set in with the extended cloudy, wet weather.”
  • Crop Insurance and Soybean Damage (Oct. 12, 2018 UTcrops News blog) by Chuck Danehower with the University of Tenn. “…the extended wet weather in late September has impacted soybean quality. Damage is ranging from minor with small discounts to extensive damage with loads getting rejected at elevators and barge points.”
  • Soybean Seed Quality Discounts (Oct. 12, 2018 UTcrops News blog) by Aaron Smith with the University of Tenn. “Quality issues will be difficult to overcome when marketing the crop. For example, damage discounts to cash prices can be $1 to $1.50 for 5 to 9 percent damage, resulting in cash soybean prices well below $7.00 per bushel.”
  • Poor Soybean Seed Quality Seen for a Second Year (Oct. 18, 2018 Ark. Row Crops) by Jeremy Ross with the University of Arkansas. “This growing season is the second year in a row where Arkansas soybean producers have seen poor quality soybean during harvest…The one major difference in 2018 was the absence of redbanded stink bug, so we can’t blame this pest for the damage we have seen….”

To some, the number of above-cited articles may appear to be overkill on the 2018 seed damage issue that has/is occurring in the U.S. However, the information in the cited articles from the various states underscores just how critical this problem is to a significant number of soybean producers in the country.

AgFax Weed Solutions


This problem is especially troublesome for producers because it can take a made yield and reduce it in both quantity and quality to a level that will likely be unprofitable in years such as 2018 with a relatively low commodity price. The reduced quality component will be penalized by dockage at the delivery point, further eroding profits.

This loss can reduce a profitable yield in the field to a level that will result in significant financial loss to the producer once harvested. Plus, elevator operators must deal with a product that is expensive to store and maintain, and nearly impossible to market.

There does not appear to be a short-term solution to this dilemma since there are no apparent effective preventive measures to protect mature seed from weathering damage if harvest is delayed by prolonged rainy periods after seed maturity.

This then leaves only one solution, and that is genetics or identifying and incorporating seed traits that will offer some protection to mature soybean seed that must withstand weathering while in the field awaiting harvest.

This fall, Drs. Wilkerson and Allen took a step toward determining if there is a difference among soybean varieties’ ability to avoid weathering damage when harvest is delayed. The premise for their assessment is that “little if any information exists regarding the differences in seed quality as it relates to soybean varieties.”

They assessed seed damage of 48 MG IV early varieties, 46 MG IV late varieties, 37 MG V early varieties, and 2 MG V late varieties that had been in the field from 32 to 50 days after physiological maturity at Stoneville, Miss.

They found that, in general, there were differences in seed quality–specifically purple seed stain and total damage–among the tested varieties. Their conclusion is “Even though this is a single location and the result from only one year of data, we think the results suggest a large amount of variability among commercially available varieties when it comes to the ability to maintain quality during periods of inclement weather.” Click here for links to the results of this activity.

The United Soybean Board recently funded a Midsouth Soybean Board (MSSB) project being conducted by Drs. Tessie Wilkerson, Rusty Smith, Vince Pantalone, and Pengyin Chen that is a first attempt to incorporate seed traits that may offer protection to mature seed that must withstand in-field weathering that results from delayed harvest. However, this project is in its infancy and any results that will assuage the seed damage problem are down the road.

As stated by Drs. Bradley and Dorrance in the above-cited articles, the pathogens associated with soybean seed damage overwinter in soybean debris left on the field following harvest. Thus, the pathogen is likely to always be present.

Couple that with the susceptible host (mature soybean seed still in the field) and a conducive environment (extended warm, rainy weather late in the season), and you have all three factors of the Disease Triangle in place to result in the above-cited high levels of seed damage in 2018. Also, the consensus gleaned from statements in several of the above articles is that any late-season fungicide applications will be ineffective against this problem.

All of the above information strongly supports:

  • The initiation of a concerted and coordinated effort among public and private soybean scientists and specialists to identify and develop traits that will protect mature soybean seed from the agents that contribute to seed damage.
  • An aggressive breeding effort among public and private company breeders and geneticists to incorporate those traits into breeding material that can be used to develop varieties that will withstand conditions that are conducive to damage to mature soybean seed prior to harvest.

Composed by Larry G. Heatherly, Nov. 2018, larryheatherly@bellsouth.net


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