Quality of 2019 Soybean Seed for Planting

It is late February, so by now producers have read the myriad articles proclaiming the potential for low quality of soybean planting seed in 2019. This is related to the widespread damage to mature soybean seed that resulted from the wet fall in 2018 that caused harvest delays.

According to a blog article on the Crop Protection Network site, numerous seed suppliers have reported that soybean seed intended for the 2019 planting have frequently tested positive for the fungus that causes Phomopsis seed decay, and this is resulting in lower-than-normal seed germination rates. Thus, it is expected that this will translate to lowered quality of planting seed for 2019, especially if these seed were stored in conditions that were not controlled to maintain a dry storage environment.

There are several things producers should absolutely do to ensure that lower quality of 2019 planting seed is accounted for.

•   Producers should check seed germination percentage [standard germination (SG) test, which is used to determine seed germination potential under ideal laboratory conditions] close to planting time to ensure that time and storage method did not adversely affect the quality of planting seed.

•   Midsouth producers who plant early into cool, wet soils should conduct (or have conducted) an accelerated aging (AA) test on their planting seed if they suspect lower-than-normal quality of those seed. It is generally recognized that the standard germination test is deficient as a measure of the potential field performance of seeds, and this is especially true for early plantings with lower quality seed. A seed vigor test more accurately measures seed properties that determine the potential for rapid and uniform emergence, and development of normal seedlings under a wide range of field conditions. The AA test is the preferred method for evaluating the vigor of soybean seeds since it evaluates the germination capacity of seeds that have been subjected to high temperature and humidity stresses for a defined period before the standard germination test. Farmers who anticipate planting early with lower quality seed should request information on seed vigor from the supplier of a seed lot, or obtain this information from an independent laboratory. Preferably, lower quality seeds should not be planted in the conditions that usually occur with early planting. However, when seed lots with a lower-than-desired germination must be used, the vigor test is especially important. Also, these seed should be planted at an increased rate to account for the lower germination percentage.

•   Above all, producers should use a broad spectrum fungicide seed treatment that has ingredients that are active against both seed- and soil-borne pathogens. This is cheap insurance that will give even lower quality planted seed the best chance to germinate and produce a healthy stand.

I encourage you to access the “Seed Treatments and Inoculants“ White Paper on this website for a list of seed treatment fungicides and fungicide combinations (contact + systemic–Table 1) to use for broad-spectrum control of soybean seed and seedling diseases, along with their efficacy ratings against specific pathogens.

The most important point to remember about seed treatment use in early plantings is that a product that is effective against both seed- and soil-borne fungal pathogens should be used to ensure a stand, especially when lower quality seed are being planted.

Composed by Larry G. Heatherly, Feb. 2019, larryheatherly@bellsouth.net