*3.1. Plant Materials and Growth Conditions*

The enhancer-trap T-DNA insertion mutant of *OsbHLH079* (LOC\_Os02g47660; PFG\_3A-01275; designated as *osbhlh079-D*) in rice was isolated from the Korean *japonica* cultivar 'Dongjin', and obtained from the Rice Functional Genomic Express Database [51]. For phenotypic characterization, rice plants were grown under natural long day (NLD) conditions in the paddy field (37◦N latitude, Suwon, Republic of Korea). Rice was also grown in growth chambers under long-day (14.5 h light, 30 ◦C/9.5 h dark, 24 ◦C) conditions or short-day (10 h light, 30 ◦C/14 h dark, 24 ◦C) conditions with 60% relative humidity. The light sources used in the artificial growth chamber were light-emitting diodes (LEDs), and the average photon flux density was around 500 μmol m−<sup>2</sup> s<sup>−</sup>1.
