This article explores the various meanings of “seed quality” and how it can and should be evaluated depending on the use of the subject seed. I have arbitrarily designated three categories for discussion.

• Germinability. This category refers to quality of seed that is intended for planting. There are defined and accepted tests to measure this quality trait. A recent study conducted at the University of Arkansas “found accelerated aging to be a valuable aid in assessing the quality of seed when compared with standard germination testing”. A summary of the results of that research are presented in an article that was recently posted on the University’s Division of Agriculture website.

The quality of seed intended for planting is an important soybean farming tool for producers to use in determining the suitability of seed for planting and the required seeding rate     to achieve an acceptable stand.

• Quality rating. Often, reports of results from soybean variety trials and soybean research studies that are conducted throughout the US include a seed quality rating for each variety or treatment. The rating is usually a number that is within a range or scale used by the conductors of each individual variety trial or research project to “score” seed quality. This score probably is not uniform in its meaning among or across variety trials/research projects of the different states or seed companies.

These ratings are used to measure the relative quality of seed among varieties or treatments in individual tests. They may not have any correlation to the quality of commodity soybeans that are graded at the point of delivery.

• Dockage. This is the deduction in price that producers are assessed for reduced quality of commodity soybean seed. The criteria used to determine the amount of dockage are established and published by the Federal Grain Inspection Service (FGIS). Unfortunately, producers have little prior knowledge of what to expect in relation to dockage until harvested seed are delivered for sale.

There are about 75 million acres of soybeans grown in the US each year. If 50 lb. of seed are planted on each of the 75 million acres, about 62.5 million bushels of soybean seed are needed for planting each year. Seed production will probably be more than that; for purposes of this discussion, a figure of 65 million bushels is used.

In contrast, an average yield of about 42 bu/acre in the US means that about 3,150 million bushels of commodity soybeans are produced each year. Thus, annual production for planting seed is about 2% of the total production of soybeans in the US, whereas annual production for commodity beans is about 98% of the total.

Of the three categories listed above, the germinability category garners by far the most attention even though it describes the seed quality of only about 2% of US production. Granted, germinability of this 2% is very important because it indicates the potential success of achieving a stand. However, the other 98% is the segment of seed production that producers are paid for, and potential quality of that seed is not known until it is too late to effect a remedy; i.e., until seed are delivered for sale.

Dockage costs producers millions of dollars in profits each year. What is needed is a prediction or estimate of just how much potential dockage a producer might expect to be assessed based on his/her use of the varied soybean farming tools that include variety, planting date, location, weather, and other factors that may affect seed quality.

Certified grain graders use the FGIS standards to assess dockage at producers’ delivery points. Supplemental information about these standards is available on this website, from the US Soybean Export Council, and in a Purdue University publication.

Plant breeders, companies that release new varieties, and researchers who explore new production methods and soybean farming tools that may influence quality of harvested seed should assess soybean seed quality based on the FGIS dockage criteria. This will provide an objective measure of a variety’s expected seed quality or how a management practice will influence seed quality as it relates to a producer’s net price at the time of sale.

The following is an example of how the FGIS grading system can be used to measure the effectiveness of a soybean farming tool on commodity seed quality.

There is a great deal of concern in the Midsouth about late-season seed decay in soybeans. Foliar fungicides are often applied to prevent or reduce the magnitude of this problem. The FGIS standards can be used to assess the effectiveness of these fungicide treatments. Consider the following.

Suppose a fungicide treatment effectively lowers dockage from 10% to 4%. If a producer has a raw yield of 50 bu/acre minus 10% dockage, the net yield without fungicide = 45 bu/acre. The net yield with the fungicide treatment is 48 bu/acre. This 3 bu/acre net yield increase x $12/bu = an increased return of $36/acre, which is in addition to the increased return from raw yield increases that are often reported when a foliar fungicide is used.

Again, dockage as a measure of seed quality should be an integral part of soybean research projects that have treatments designed to improve this trait.

I encourage all soybean breeders and researchers to become familiar with the FGIS grading system, and to use it to assess seed quality where appropriate. If necessary, samples of seed from breeding and research plots can be collected and sent to a grading facility for this determination. This will provide a uniform, consistent estimator of what producers might expect pertaining to seed quality when they select soybean farming tools for the 98% of the US soybean acres that are grown for commodity beans.

larryheatherly@bellsouth.net