The effect of environment on seed composition of tofu and natto soybean cultivars

Farmers traditionally manage soybean [Glycine max (L.) Merr.] to maximize yield. To produce specialty soybean seed for use in manufacturing tofu and natto products, a specific seed composition is desired. The objective of this study was to determine if planting date affects sucrose, raffinose, and stachyose composition in seeds of tofu and natto soybean cultivars. Planting date effects on protein and oil content and yield were also studied to determine if desirable combinations of all important traits are possible. Four tofu, two natto, and four commodity soybean cultivars were planted on three dates near Columbia, MO in 2004 and 2005. Seed composition was measured by near infrared (NIR) and high performance liquid chromatography (HPLC). In 2004 and 2005 the planting date by cultivar interaction was significant for protein, sucrose, and raffinose. For two tofu cultivars, 5346BP22 and 53462163, yields were not significantly different from the commodity cultivars. Natto cultivars yielded less than tofu and commodity cultivars for both years. Two tofu cultivars, 5346BP22 and 534545, had high percentages of sucrose. For natto cultivars, although the soluble carbohydrates were lower than desired, protein was high and oil was lower than average.