INTERACTION OF FLC AND LATE-FLOWERING MUTATIONS IN ARABIDOPSIS-THALIANA

The phenotype caused by mutations that affect the timing of flowering in Arabidopsis thaliana has been most extensively analyzed in the Land sberg erecta (Ler) genetic background. In Ler, the late-flowering phen otype of FRIGIDA and mutations in LUMINIDEPENDENS is suppressed by the Ler allele of FLC. In this study, the interactions of nine mutations conferring late flowering with the FLC allele of the Columbia ecotype (FLC-Col), which does not suppress late flowering, were examined. The effect on flowering time of combining six of the mutations with FLC-Co l was additive; plants containing FLC-Col with fd, gi, fwa, fha, ft an d fe flowered slightly later than plants containing these mutations wi th the Lei allele of FLC. In contrast, a synergistic effect was observ ed between FLC-Col and three mutations; fca, fpa, and fve plants becam e extremely late flowering when combined with FLC-Col. Maximum delay i n flowering for the majority of the mutant strains required FLC-Col in a homozygous state, although for fpa and fe a single copy of FLC-Col allowed maximum lateness. In addition, the fd and fe mutations became more dominant in the presence of FLC-Col.