Introduction
 

Plants have evolved sophisticated mechanisms to ensure that they flower when the chances of pollination, seed development and seed dispersal are highest. For most plants this means that flowering is restricted to a particular time of year.

The timing of flowering is also very important for crops as it has major impacts on yield and quality. But how does a plant “know” what time of year it is? Many plants, including cereals, use environmental cues, particularly the length of the day (photoperiod) and extended periods of low temperature (vernalization).

During domestication the responsiveness of crops to these signals has altered so that they can now be grown in regions outside the ecogeographical limits of their wild ancestors.

In our research we study genetic variation in barley and wheat for response to photoperiod and vernalization. For example, UK winter barley (sown in the autumn) has a requirement for vernalization and flowering is promoted by long photoperiod. UK spring (spring sown) barley has no requirement for vernalization and is less responsive to long photoperiod (tell me more).

Our aims are:

to understand how barley’s responses to these cues varies and how this provides adaptation to different farming environments.

and
to provide knowledge and resources that plant breeders can use to enhance adaptation and sustainability of production.
 

We are also interested in the evolution of flowering time control. Flowering is being extensively studied in the model plant Arabidopsis thaliana and we want to understand whether the genetic basis of flowering time regulation is conserved. In other words, do cereals and Arabidopsis have the same regulatory pathways inherited from their common ancestor? Where they have, Arabidopsis provides fast-track access to important genes in cereals.

Four genetic pathways controlling flowering have been identified In Arabidopsis.  (LINK)

Photoperiod
The photoperiod pathway promotes the expression of floral pathway integrators called LEAFY (LFY), FLOWERING LOCUS T (FT) and AGAMOUS-LIKE20 (AGL20) in long days.

Vernalization
FLOWERING LOCUS C (FLC) represses flowering by preventing the expression of FT and AGL20. FLC expression is removed by exposure to extended periods of cold (vernalization).

Autonomous
The autonomous pathway comprises genes that are involved in FLC regulation.

Gibberellic acid
The plant hormone gibberellic acid (GA) is also involved in the regulation of LFY and AGL20.