Quantitative variation in maize kernel row number is controlled by the FASCIATED EAR2 locus

Abstract

Domestication of cereal crops, such as maize, wheat and rice, had a profound influence on agriculture and the establishment of human civilizations. One major improvement was an increase in seed number per inflorescence, which enhanced yield and simplified harvesting and storage. The ancestor of maize, teosinte, makes 2 rows of kernels, and modern varieties make ∼8-20 rows. Kernel rows are initiated by the inflorescence shoot meristem, and shoot meristem size is controlled by a feedback loop involving the CLAVATA signaling proteins and the WUSCHEL transcription factor. We present a hypothesis that variation in inflorescence meristem size affects kernel row number (KRN), with the potential to increase yield. We also show that variation in the CLAVATA receptor-like protein FASCIATED EAR2 leads to increased inflorescence meristem size and KRN. These findings indicate that modulation of fundamental stem cell proliferation control pathways has the potential to enhance crop yields.