**6. Conclusion**

Effects of climate change and the growing world population along with reduced natural resources pose a major challenge for crop production and food security, especially in the developing countries. In this chapter, we have provided an overview of genetic regulation and synthesis of seed reserves, the role of phytohormones, and the influence of environmental factors on metabolic processes during seed filling in different plant species. To increase crop productivity, it is necessary to understand seed development processes together with reserve synthesis and accumulation under normal and stress conditions, and the control and regulation at the molecular and hormonal levels in seeds during seed filling. We have summarized recent studies on seed filling processes by highlighting the effects of phytohormones on the seed filling process and their interactions the effects of abiotic stress conditions on seed reserve quality and yield during the seed filling process.
