**Abstract**

The synthesis of seed storage reserves occurs during seed filling, and many seeds contain large and characteristic levels of polymeric reserves. Storage reserves are found in the endosperm of cereal seeds and in the endosperm and/or cotyledons of dicot seeds depending of the plant crop species. Recently progress has been made in understanding the complex network of genetic regulation associated with seed filling. These advances in storage reserve quantity and nutrient quality contribute to a comprehensive understanding of reserve composition, synthesis, and regulation. Phytohormones such as abscisic acid (ABA), cytokinin, gibberellic acid, Indole-3-acetic acid (IAA), ethylene and their interactions play critical roles in seed filling and development. At different stages of seed development, the levels of different hormones such as ABA, IAA zeatin and zeatin riboside changes gradually from the beginning of the process to maturity. In addition, the quality and yield of seed storage reserves are significantly affected by the environmental conditions before and during the synthesis of the reserves. Given the fateful importance of seed storage reserves for food and feed and their use as sustainable industrial feedstock to replace dwindling fossil reserves, understanding the metabolic and developmental control of seed filling will be an important focus of plant research.

**Keywords:** early maturation, environmental factors, genetic regulation, plant hormones, storage reserves
