The use of soil might be an option for the germination testing of untreated soybean seed with fungal problems.
By Michael Stahr
There is another testing option available for soybean seed lots that have low warm germination results due to infection by Phomopsis and/or Fusarium. Seed treatment is a viable option for many seed lots as germination results have been documented to commonly increase 5-15% or more. However, for seed lots where treatment is not an option the use of soil in at the warm (standard) germination test can make a significant difference. Volume 1 of The Association of Official Seed Analysts (AOSA) Rules for Testing Seeds does not allow soil to be used for first time testing of any type of seeds, but it can be used as a retest substrate. At the Iowa State University Seed Lab we used this option on four seed samples and the increase in germination results were 5, 22, 25 & 27 percent when initial scores were 70, 52, 55 and 61 percent, respectively. Soil was sprinkled over seeds planted on crepe cellulose paper (Versapak). The results are obviously not an exhaustive study, but they show that the use of soil might be an option for the germination testing of untreated soybean seed with fungal problems.