Earlier harvest and drying of soybean seed within intact pods maintains seed quality

Abstract

Soybean [Glycine max (L.) Merr.] seed quality (viability and vigor) is critical to seed producers, emphasizing the need to maximize the quality of the harvested seeds. Currently, soybean seeds are harvested at a moisture content of ≤ 160 g kg -1 , similar to the moisture content of harvested soybean grain. However, soybean seed quality peaks at physiological maturity (PM). Allowing soybean seeds to desiccate in the field increases vulnerability to seed deterioration, disease, and harvest losses. Early harvest of soybean seeds and drying within intact pods might maintain seed quality. Our research examined the effect of maturity stage (green-, yellow-, or brown-pod), drying temperature (27°C ± 2, 31°C ± 2, or 41°C ± 2), and pod integrity (pod intact or removed) on soybean seed quality. Seeds were harvested in 2009 and 2010 and dried within stacked tray driers. Drying podded, yellow-pod maturity seeds at ambient temperature (27°C ± 2) protected seeds from rapid desiccation and seeds exhibited similar seed quality characteristics as those harvested at brown-pod maturity stage. A drying temperature of 41°C ± 2 greatly reduced seed quality at both levels of pod integrity for immature harvested seeds (green-pod). Harvesting soybeans at the yellow-pod stage has the greatest potential for