Soybean Seed Size and Pretreatment: Effect on Germination and Seedling Emergence.

Soybean (Glycine max) is an important source of protein and oil, and has nutriceutical and pharmaceutical benefits. Soyfood consumption in the U.S. has dramatically increased as more people became aware of soyfood containing highly digestible protein, all essential amino acids and a high concentration of isoflavones. Popular soyfood, soymilk and tofu, and the miracle “super-food”, edamame, are all produced from large-seeded soybeans. However, germination rate and seedling vigor of large seeds is usually lower than medium and small seeds. The objectives of this study is to; 1) Determine difference in germination of  soybean seeds in various seed size groups, 2) Determine effect of pre-treatment (soaking and or fertilizer application) on germination and emergence, and 3) Explore the effect of germination and emergence on food-type soybean yield and quality. Six soybean varieties varied in seed size (<10g/ 100 seeds, between 12 and 16 g/100 seeds, and >20g/ 100 seeds). Seed germination and emergence were tested under laboratory and field conditions. Preliminary results showed that small seeded varieties have better germination under both field and laboratory conditions. Also under laboratory conditions, N fertilizer treatment delayed and resulted in low germination. Pre-soaking in water for more than 5 hours reduced germination and seedling emergence especially in the large seeded varieties.