The present invention relates to plant genes involved in regulating flowering, and especially to genes involved in the induction of flowering in response to cold, or vernalization. In particular, the present invention provides the identification, cloning, and characterization of genes involved in vernalization, and specifically of VIP genes, as well as to the proteins encoded by these genes, and to methods of using the VIP genes and proteins. Mutants of VIP genes, where the mutation is a knock-out mutation, confer a vernalization independence, or constitutively vernalized, phenotype in a plant which in the non-mutant form requires vernalization to flower.