Values shown are the mean number ± SD of rosette leaves at the time of flowering. At least 12 plants of each line were used, and the experiments were repeated at least twice. Statistical analysis was performed by one-way ANOVA. The asterisks (**) and (*) indicate differences that are significant at the P < 0.001 and P < 0.01 levels respectively. Acronyms are as described in Fig. 1.