Imbibitional Chilling Sensitivity Among Soybean Cultivars1

Abstract

Fifteen soybean (Glycine max (L.) Merr.) cultivars were screened for sensitivity of embryos to imbitional chilling injury. All were susceptible to injury, but sensitivity varied greatly. Some showed no injury at 7 C while others were injured at 17 C. Embryos of earlier maturing cultivars tended to be more susceptible to imbibitional chilling injury than those of later maturing cultivars. This relationship of time of maturation to chilling sensitivity was confirmed using near‐isogenlc lines of ‘Clark’ soybean, a cultivar possessing various genes that advanced or delayed maturity. Earlier maturing lines were more sensitive to chilling than later maturing lines. Leakage of solutes during imbibition, measured as OD280, was negatively correlated with germination when near.isogenic strains were compared, but was not closely correlated when different cultivars were compared.It is proposed that seed maturation occurring later in the growing season, during periods of relatively low temperature, hardens seeds against chilling injury.