Hormonal Regulation of Spikelet Development

Abstract

Many of the identified panicle development genes of the rice plants are homologous to known hormone genes. The class of plant hormones includes both positive and negative growth regulators. In rice, hormone-related biosynthetic pathways have been targeted for yield improvement since long bereft of any yield advantage hitherto. In the heterogeneous architecture rice panicle spikelet, position-specific grain growth is surmised coincidental to variation in balance between different hormones. The abundance of GA, auxin, cytokinin, ABA, and brassinosteroids improves grain yield whereas enhancement of ethylene synthesis, jasmonic acid production, and IAA perception inhibits grain filling. Hence, it has been obligatory to identify and characterize the expression of individual hormone-regulated panicle development genes to break yield frontiers in rice.