The article reports the positional cloning of the wheat vernalization gene VRN2, which is a dominant repressor of flowering that is down-regulated by vernalization. The loss of function of VRN2 results in spring lines, which do not require vernalization to flower. RNA interference (RNAi) of VRN2 accelerated flowering time in transgenic winter wheat plants by more than a month. The VRN2 gene was mapped to chromosome 5A and identified as ZCCT1, a gene encoding a CO-like protein with a CCT domain. The down-regulation of ZCCT1 during vernalization was accompanied by an increase in VRN1 transcription, consistent with epistatic interactions between VRN1 and VRN2. Allelic variation at ZCCT1 was associated with spring growth habit in cultivated wheat accessions. RNAi of ZCCT1 transcripts in transgenic wheat plants confirmed its role as VRN2. The study highlights the importance of flexible regulation of flowering time in the wide adaptability of temperate cereals.The article reports the positional cloning of the wheat vernalization gene VRN2, which is a dominant repressor of flowering that is down-regulated by vernalization. The loss of function of VRN2 results in spring lines, which do not require vernalization to flower. RNA interference (RNAi) of VRN2 accelerated flowering time in transgenic winter wheat plants by more than a month. The VRN2 gene was mapped to chromosome 5A and identified as ZCCT1, a gene encoding a CO-like protein with a CCT domain. The down-regulation of ZCCT1 during vernalization was accompanied by an increase in VRN1 transcription, consistent with epistatic interactions between VRN1 and VRN2. Allelic variation at ZCCT1 was associated with spring growth habit in cultivated wheat accessions. RNAi of ZCCT1 transcripts in transgenic wheat plants confirmed its role as VRN2. The study highlights the importance of flexible regulation of flowering time in the wide adaptability of temperate cereals.