Method to predict flowering time to inform crop selection and breeding

Weather Window - rapeseed CREDIT Phil Robinson

Technology reference: J20RM1

Proposed use

Vernalization is the induction of a plant’s flowering process by exposure to the prolonged cold of winter, or by an artificial equivalent.

This invention is a method to enable selective breeding of Brassicaceae family plants including oilseed rape, broccoli, and turnips with desired vernalization requirements to optimise commercial production.

Problem addressed

Vernalization is a period of prolonged cold exposure that controls flowering time in plants.

Saturating vernalization requirements allows for flowering synchronisation between plants of the same cultivar.

In an agricultural setting, knowledge of the vernalization requirements of crops is essential to coordinate cultivation and harvest.

A method has been developed to predict vernalization requirements in crop cultivars. This method aids selective breeding to achieve synchronised flowering in the desired climate and environment.

Technology overview

The floral repressor FLOWERING LOCUS C (FLC) controls the cold requirements for flowering, and natural variation in FLC expression leads to differences in flowering time.

Many key crops are polyploid and have multiple copies and variants of FLC.

For example, Brassica napus (oilseed rape) has nine copies of the FLC paralogue and the many varieties of the crop have different vernalization requirements.

The combined effects of the total FLC expression dynamics are responsible for the vernalization requirements in different B. napus crop types, rather than an individual contribution of the FLC paralogues.

Quantitative differences in total BnaFLC expression levels changes vernalization requirements. Flowering is initiated when the total BnaFLC expression level falls under a certain threshold; how long it takes before this moment is reached is determined by the pre-vernalization BnaFLC expression level, the relative contribution of the different BnaFLC paralogues and the decay rate of their expression in response to cold.

Based on these findings a method had been developed to predict the chill time required for the FLC expression to reduce to the pre-determined threshold to allow flowering.

This vernalization requirement can be calculated using the expression of total FLC under normal growth conditions and its decay during vernalization, which could either be measured directly, or inferred from the relative contribution of the different FLC paralogues.

The threshold can be determined from the FLC expression levels in a spring type cultivar that does not require any vernalization, or directly from the cultivar of interest in vernalization experiments.


  • Selecting crops with a specific vernalization requirement synchronizes the transition to flowering, better informing the grower of the optimum time to harvest their crop and consequently improving crop yield
  • Our method predicts vernalization requirements in plants. In particular, the Brassicaceae family including oilseed rape, broccoli, and turnips
  • Vernalization predictions allow plant cultivars to be selected and crossed to suit the intended geographical region and environment

Intellectual property information

Pending PCT Patent Application (unpublished) – “Regulation of flowering time”.

Published paper(s)

Calderwood, A., Lloyd, A., Hepworth, J., Tudor, E.H., Jones, D.M., Woodhouse, S., Bilham, L., Chinoy, C., Williams, K., Corke, F., Doonan, J.H., Ostergaard, L., Irwin, J.A., Wells, R., Morris, R.J., 2020. Total FLC transcript dynamics from divergent paralogue expression explains flowering diversity in Brassica napus. New Phytol.

Inventor information

  • Professor Richard Morris – Group Leader at the John Innes Centre with expertise in mathematical and computational approaches to provide mechanistic insights in complex phenomena
  • Dr Judith Irwin – Former Group Leader at the John Innes Centre focused on translating fundamental research on the control of flowering to improve Brassica crop productivity
  • Professor Dame Caroline Dean – Group Leader at the John Innes Centre with expertise in flowering time genetics
  • Dr Alex Calderwood – Former postdoctoral scientist at the John Innes Centre in the group of Prof Morris, where he investigated how gene networks work to control developmental transitions in Brassica, particularly the switch to flowering. He is now a research associate working at the Cambridge Stem Cell Institute