RESUMO
Crop production and productivity must be increased to provide a balanced diet for the global population. The entire genome sequences of crop species allow the elucidation of genes that regulate important traits related to the final crop seed yield, which frequently depends mainly on seed size. Seed size is a major factor that controls seed quantity and it is strongly affected by various biotic, abiotic and genetic factors. Epigenetic marks in the genome and phytohormones are also important factors affecting seed growth and development. Several genes are known to be involved in the control of seed size, but their interaction and functional characterization have yet to be resolved. In this review, we discuss the different factors that govern seed size in cereal crops and Arabidopsis.