Seed quality is rarely a widespread issue in soybean; however, in 2008 it will pay for growers to check the percent germination of each seed lot that they purchased and adjust their seeding rate accordingly.

In a normal year most soybean seed is sold at 92% germ or greater. In 2008, growers may find several varieties sold at 85% germ and some may be marketed as low as 80% germ. The lowered germ in seed available now was caused by adverse environmental conditions during the soybean seed-fill period.

Our hypothesis is that dry conditions in the R4 (full pod) and R5 (beginning seed) growth stages limited seed size, then substantial rainfall in the mid to late R6 (full seed) growth stage caused an unexpected late season expansion in seed size. This surge caused the soybean seed coat to be thinner than normal thus adversely impacting seed quality.

As the seed is mechanically handled during the harvest, transportation, cleaning, and bagging process, damage can be inflicted on seed with such a thin seed coat. It is also being suggested that some seed lots with low germ (80%) caused by thin seed coats should not be treated with a fungicide and/or insecticide in 2008. The rationale behind this is that the mechanical process of treating may further decrease the already low germination.

We are not suggesting that seed treatments be avoided in 2008, we are just cautioning growers to consider the cost benefit for those few varieties that have low germs caused by thin seed coats.

Read the rest of the article here

SOURCE: Shawn P. Conley, State Soybean and Wheat Extension Specialist, John Gaska, Outreach Specialist, University of Wisconsin, Madison