Barley mutants with low rates of endosperm starch synthesis have low grain dormancy and high susceptibility to preharvest sprouting.

• Studies of embryo dormancy in relation to preharvest sprouting (PHS) in cereals have focused on ABA and other hormones. The relationship between these phenomena and the rate of grain filling has not been investigated. • A collection of barley mutants impaired in starch synthesis was assessed for preharvest sprouting in the field.