A critical review of the factors influencing pre-harvest sprouting of wheat

Pre-harvest sprouting (PHS) is a global issue affecting a multitude of crops, including wheat (Triticum aestivum L.). The combination of conducive conditions and a lack of genetic seed dormancy results in the sprouting of intact grain at or prior to harvesting. The initiation of germination synthesizes gibberellic acid resulting in the activation of the alpha-amylase synthesis via a calcium-dependent signal transduction pathway. Alpha-amylase synthesized via this pathway degrades the endosperm, decreasing bread-making quality. A commonly used indicator for bread-making quality is the Hagberg Falling Number. Environmental, phenotypic, genetic, and management factors influence the susceptibility of wheat to PHS. Rainfall, temperature, and relative humidity are commonly associated with PHS. The combination of these conditions results in the greatest severity of PHS. Morphological features such as awns and epicuticular waxes may increase the quantity of rainfall retained against the grain, increasing the risk of PHS. Similarly, management factors such as fertilization and fungicide application also may increase the risk of PHS occurring. Further research is necessary to understand the mechanisms and impact of management factors on PHS. Additionally, further investigations are needed to explore how environmental and genotypic interactions affect PHS susceptibility.