PMC

(A) Single recombinants at the 1DL QTL interval that segregate for late flowering and early flowering in the BC₂F₅ SSD lines of a cross between Spark and Rialto. Recombinant classes 1–4 are early flowering while recombinant classes 5–8 are late flowering. The data show that the earliness allele is distal to the TaBradi2g14790 marker. (B) Recombinants containing heterozygous regions as well as double recombinants at the 1DL QTL interval that segregate for late flowering and early flowering in the BC₂F5 SSD lines of a cross between Spark and Rialto. Recombinant classes 9–14 are late flowering while recombinant classes 15–28 are early flowering. Key a=Spark 1DL Eps-D1 allele, b=Rialto 1DL allele and a/b represents heterozygous for a and b. The data also shows that the earliness allele is linked with the 1DL deletion.

(a,b) Flowering time measurements as total leaf number (a) and days to flowering (b) of LD-grown Col-0 wt Arabidopsis plants compared to loss-of-function lines of FRS7 or FRS12. (c,d) Flowering time measurements as total leaf number (c) and days to flowering (d) of SD-grown Col-0 wt Arabidopsis plants compared to loss-of-function lines of FRS7 or FRS12. Values represent the average of 12 biological replicates±s.e.m.; **P<0.01, ***P<0.001, t test. (e) Representative photographs comparing a frs7-1;frs12-1 double mutant to a Col-0 wt plant flowering under SD growth. Scale bars, 5 cm.

(a) Flowering time of GsWRKY20ox plants was accelerated under both LD and SD conditions.
(b) qRT-PCR analysis of GsWRKY20 transcript levels in WT and the three homozygous 35S :: GsWRKY20 lines. Expression of ACTIN2 was used as an internal control. The experiment included three fully independent biological repeats, and three technical repeats and the mean value is shown. (c) Average flowering time of WT and GsWRKY20ox plants at the time of flowering under LD conditions.
(d) Average rosette leaf numbers of WT and GsWRKY20ox plants at the time of flowering under LD conditions.
(e) Average flowering time of WT and GsWRKY20ox plants at the time of flowering under SD conditions.
(f) Average rosette leaf numbers of WT and GsWRKY20ox plants at the time of flowering under SD conditions.
All values in (c, d, e, f) are means (±S.E.) from three independent experiments (At least 30 seedlings per experiment). Data were analyzed statistically using the t-test, Asterisk and double asterisks indicate significant differences from the corresponding WT at 0.01 <P< 0.05 and P< 0.01, respectively.

Schematic illustration of Arabidopsis flowering time pathways. The long-day, autonomous, and GA pathways promote flowering of Arabidopsis under standard long-day conditions, and are represented respectively by the CO, FCA, and GA1 genes that are discussed in the text. The autonomous pathway acts by repressing expression of the floral inhibitor FLC. The genetic data presented here indicate that these three pathways are required for flowering to occur, and suggests that the autonomous pathway accelerates flowering by facilitating the activity of the long-day and GA pathways. Vernalization promotes flowering by repressing expression of the floral inhibitor FLC, but detailed comparison of the flowering times of vernalized co-2 fca-1 ga1-3 triple mutants and co-2 ga1-3 double mutants suggests that vernalization may also promote flowering independently of FLC, as represented by the dotted line.