TABLE 2.

Example of how variation in vernalization requirement arises.

Species	Line	Vernalization requirement	Note	References
B. rapa	Yellow Sarson (C634)	−	Low level of BrFLC2 expression in pre-vernalized sample	Li et al., 2009
	Yellow Sarson (L147)	−	Deletion in exon 4 and intron 4 in BrFLC2	Wu et al., 2012
	Nou-6 (Chinese cabbage)	++	Low repression rate of BrFLC1 and BrFLC5 following vernalization	Kakizaki et al., 2011
	Tsukena No. 2 (Leafy Green/Tsukena)	+++	Low repression rate caused by TE insertion in BrFLC2 and BrFLC3	Kitamoto et al., 2014
B. oleracea	Green Comet (broccoli)	−	Frameshift due to 1-bp deletion in exon 4 of BoFLC2	Okazaki et al., 2007
	Inbred lines (cauliflower)	−	Frameshift due to 1-bp deletion in exon 4 of BoFLC2	Ridge et al., 2015
	E9 (purple sprouting broccoli)	++	High reactivation rate of BoFLC2 expression on return to warm condition	Irwin et al., 2016
B. napus	Westar etc. (spring type)	−	Loss of BnaFLC.A10 function by TE insertion in the first exon	Yin et al., 2020
			Loss of BnaFLC.A02 function by TE insertion in the exon 7
	NIL L06 (spring type)	−	Loss of BnaFLC.A02 function by 2,833 bp insertion in the intron 1	Chen et al., 2018
	Zhongshuang 11 etc. (semiwinter type)	+	BnaFLC.A10 expression level before and following vernalization is lower than that in winter type, which may be due to TE insertion in the promoter region	Yin et al., 2020
	Darmor (European winter type)	++	Higher expression levels of BnaFLC.A02 before vernalization, lower repression rate following vernalization, and higher reactivation rate on return to warm conditions of BnaFLC.A02	Tudor et al., 2020
	Tapidor etc. (European winter type)	++	Low rate of BnaFLC.A10 repression following vernalization, which may be due to TE insertion in the promoter region	Hou et al., 2012; Yin et al., 2020

−, low or no vernalization requirement; +, vernalization requirement.