Probable transcription factor involved in the regulation of flowering time under long day (LD) conditions. Plays a major role as repressor of flowering. Controls flowering time by negatively regulating the expression of EHD1 and HD3A. Interacts with HD16/EL1. Expressed in the apical meristem, developing leaves, leaf sheaths of young seedling, root meristem, epidermal layer of developing stems and branch-primordia of developing panicles. Circadian-regulation under long day (LD) conditions. Expression increases during daytime, peaks at the end of the light period and gradually decreases during the dark period. Phosphorylated at Ser-68 by HD16/EL1, a casein kinase 1. Early flowering phenotype under long day (LD) and natural day (ND) conditions. Decreased plant size, number of grains per panicle, yield and dry weight per plant.