Seed Dormancy: Approaches for Finding New Genes in Cereals

Seed dormancy is a property of mature seeds which blocks germination under favourable conditions and which is acquired during seed development. It is a widespread trait which assists survival of seeds in nature, and its presence in many crop species is highly desirable. In cereals, dormancy at harvest is a desirable trait because it prevents the premature germination of seeds in the field, called pre-harvest sprouting. Dormancy is initiated early during seed development, and its maintenance is dependent on a complex interaction between environmental and genetic factors. The plant hormones abscisic acid (ABA) and gibberellins (GAs) play major roles in the initiation, maintenance and loss of seed dormancy. The decay of dormancy can be influenced by several factors including environmental conditions (i.e. cold and light), nitrogen applications, seed coat characteristics and after-ripening. Despite the importance of seed dormancy in agriculture, the factors controlling its development and decay are not well understood. This review is focused on different strategies used for finding dormancy-related genes in model plants and on biotechnological approaches for modifying dormancy in cereals.