Seed Dormancy: Preharvest Sprouting

Abstract

Preharvest sprouting (PHS) takes place when germination occurs in the mother plant as a result of rainy weather prior to crop harvest. It has a wide range of consequences, which go from immediate viability loss upon grain desiccation, to low storability and dramatic alterations in grain quality. Resistance to PHS might be related to morphological characteristics of the inflorescence. However, timing with which the grains are released from physiological dormancy usually explains the variability in sprouting behavior. Physiological dormancy is under hormonal control and, for that reason, improvement of the sprouting behavior of cereal genotypes relies on our understanding of processes such as hormone (e.g., abscisic acid and gibberellin) metabolism and signaling. Hormonal studies yielded several candidate genes that have been identified as regulatory sites. These and other genes identified through genetic studies represent a potential technological battery for tackling the risk of sprouting in cereals.