Hormonal regulation of inflorescence and intercalary meristems in grasses.

Hormones played a fundamental role in improvement of yield in cereal grasses. Natural variants affecting gibberellic acid (GA) and auxin pathways were used to breed semi-dwarf varieties of rice, wheat, and sorghum, during the "Green Revolution" in the 20th century. Since then, variants with altered GA and cytokinin homeostasis have been used to breed cereals with increased grain number. These yield improvements were enabled by hormonal regulation of intercalary and inflorescence meristems. Recent advances have highlighted additional pathways, beyond the traditional CLAVATA-WUSCHEL pathway, in the regulation of auxin and cytokinin in inflorescence meristems, and have expanded our understanding of the role of GA in intercalary meristems.