Fig. 3.

Integration of environmental signals into spikelet initiation through florigen pathway. The florigen gene FT plays important role in response to environmental signals, including day length and temperature, which in turn promotes plant flowering by activating the expression of reproductive identity genes, such as MADS TFs SOC1 and AP1 in Arabidopsis, OsMADS15, OsMADS14 and OsMADS18 in rice, VRN1 in wheat and barley. The nucleotide variations of genes involved in florigen pathway, such as Hd1, DTH8, Ghd7 and DTH7 in rice, VRN3 and VRN1 in wheat and barley, as well as duplication of FT family genes contribute to environmental adaptation, and could be targeted in plant breeding