QTL profiles of LTM × SAD12 population, showing chromosomal regions with significant QTLs (upper panel) and their additive effect across environments. SD ; short day, LD ; long day, OE : outdoor environment, CA : cold acclimation, FT : freezing treatment, 1DF : 1 day post freezing, MF : mild freezing (Jan., 2012), SF : severe freezing (Feb., 2012).