While many tropical plants have been adapted to temperate cultivation, few temperate plants have been adapted to the tropics. Originating in Western Europe, Brassica oleracea vernalization requires a period of low temperature and BoFLC2 regulates the transition to floral development. In B. oleracea germplasm selected in Taiwan, a non-vernalization pathway involving BoFLC3 rather than BoFLC2 regulates curd induction. In 112 subtropical breeding lines, specific haplotype combinations of BoFLC3 and PAN (involved in floral organ identity and a positional candidate for additional curd induction variation) adapt B. oleracea to high ambient temperature and short daylength. Duplicated genes permitted evolution of alternative pathways for control of flowering in temperate and tropical environments, a principle that might be utilized via natural or engineered approaches in other plants. New insight into regulation of Brassica flowering exemplifies translational agriculture, tapping knowledge of botanical models to improve food security under projected climate change scenarios.