Probable transcription factor involved in the regulation of flowering time under long day (LD) conditions. Functions as repressor of flowering, independently of HD1 and GHD7. Controls flowering time by negatively regulating the expression of EHD1 and HD3A (PubMed:20566706, PubMed:21148627). Regulates plant height by promoting cell elongation in the internodes (PubMed:20566706). Component of the NF-Y/HAP transcription factor complex (By similarity). Heterotrimeric transcription factor composed of three components, NF-YA, NF-YB and NF-YC. NF-YB and NF-YC must interact and dimerize for NF-YA association and DNA binding (By similarity). Interacts with NFYC2, NFYC4 and NFYC6 (PubMed:26542958). Expressed in roots, culms, nodes, leaf blades, leaf sheaths and young panicles. Circadian-regulation under long day (LD) conditions. Expression increases in the middle of daytime, peaks around the end of the light period and gradually decreases during the dark period and beginning of daylight. 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. Belongs to the NFYB/HAP3 subunit family.