Controlling Supply Quality and Waste in Brassica vegetables: Understanding the genetics of maturity to breed varieties in response to climate change.

Lead Research Organisation: John Innes Centre
Department Name: Cell and Develop Biology

Abstract

Flowering is a key component of plant adaptation, affecting geographical distribution and suitability for farming practices. It is highly relevant to yield, quality and environmental considerations as flowering at the appropriate time ensures best use of the available growing season, promoting sustainability and reducing the need for inputs. The genus Brassica includes species with many morphological forms that are cultivated for use as vegetables, oils, fodder and condiments, and much of this morphological diversity can be attributed to variation in flowering time. Biennial cultivars require a period of cold treatment (vernalization) to induce flowering. This flowering behaviour is critical for the production of some vegetable forms and for adaptation to certain agricultural practices, such as planting of overwintering cauliflower varieties. Annual Brassica cultivars do not require cold treatment to flower, although some annuals can respond to vernalization by flowering earlier and more uniformly. How different varieties respond to vernalization has a big effect on when and how they mature. Many vegetables are harvested and eaten at the vegetative stage, prior to flowering. Successfully predicting the timing and length of the vegetative phase has a big influence on the quality and commercial return from the crop. For other vegetables it is the timing of the floral transition that is critical. In this project we will identify genes which can exert greater or lesser control on the vernalization process with the aim of using this information to produce parent lines and hybrids which have a more predictable harvest period. We will relate variation at these loci to performance under present and historical weather patterns to associate specific allelic combinations with maturity under different climatic conditions. Knowledge of key Brassica vernalization genes and how they vary in different vegetable Brassicas will allow us to address key questions about the impact of climate patterns on the availability of UK-produced quality Brassica vegetables.

Technical Summary

The UK has a strong base in flowering time research, especially in the control of vernalization. From the work of Caroline Dean at the John Innes Centre, and others, much is now known about the genetic pathways regulating vernalization in the model plant Arabidopsis thaliana. Using the Genetic resources developed in Horticulture LINK project HL0186 we will identify the genes controlling vernalization in Brassica and exploit this information to develop tools to speed up the breeding in Brassica vegetable crops. We will exploit the continually expanding genomic resources in Brassica to map paralogues of key Arabidopsis genes involved in the control of flowering with a focus on known vernalization genes. We will use the most recent developments in the Dean lab to expedite this choice, together with Brassica: Arabidopsis synteny to identify putative candidates underlying QTL mapped under different temperature x time treatments. Identification of candidate genes for selected QTL will be confirmed by co-segregation of alleles with maturity phenotypes in backcross progeny. Early and late alleles of putative candidates will be transformed into appropriate Arabidopsis mutants to test complementation. We will demonstrate the generality of the findings by analysing allelic variation at these loci in current cauliflower varieties and compare this with known vernalization responses. To identify novel, functional allelic variation a wide range of germplasm will be screened at candidate gene loci including the Defra funded Diversity Fixed Foundation Sets (DFFS) for B.oleracea and the wild C genome being produced at Warwick HRI. Allelic variation at candidate loci will be related to performance under past and present weather patterns. We will use the UKCP scenarios, and in particular the Weather generator, to model future growing conditions. We will link past and current variety performance to inform future breeding strategies for continuity of production.

Planned Impact

All UK Brassica growing areas are subject to problems caused by climate changes influencing harvest dates. Increased understanding of the vernalization process in Brassica and its effect on maturity under a range of climate scenarios will result in the breeding of varieties with a more predictable, robust response to the effect of temperature. The information learnt from this project will be directly applicable not only to Purple Sprouting Broccoli, but to other Brassica vegetable crops such as green broccoli, calabrese and cauliflower. The introduction of F1 hybrids which give more predictable maturity will help to sustain the UK market share, provide flexibility and enable the industry to better adapt to both environmental constraints and changing market demands. The proposed project presents an exceptional opportunity to expand the work begun in Horticulture LINK Feasibility study HL0186 to translate basic research on a reference species to horticulturally important crops and to address issues relating to the key cross Research Council objective: Living with environmental change. The problem of planning for a consistent supply of quality product to the supermarkets is one growers have had to face since the introduction of high quality F1 hybrids. The supermarkets require a year-round supply and growers endeavour to meet this demand from UK and imported produce. The provision of varieties with more robust response to changes in temperature should help them to plan their product supply more effectively; resulting in a more reliable supply from the UK market, which in turn should result in more stable prices and less waste caused by gluts of produce. In addition the combined analysis with climatic data should aid the breeding of new varieties to help mitigate the impact of future climate patterns on the availability of UK-produced quality Brassica vegetables. The value of the total UK Brassica vegetable crop is £330M (Defra 2007 provisional statistics). The Prple Sprouting Broccoli market is around £4M and the UK is approximately 85% self sufficient. Customer research indicates that demand for the 9 month period when it is not in good supply would equal the 3 months when it is freely available and therefore there is a big scope for improvement. The current cauliflower and green broccoli market is around £200M, and the UK is approximately 50% self sufficient (2007 Defra statistics). The aim of this project is to provide tools and information that will help growers maintain their current competitive position and to support a viable and sustainable industry that can adapt to market demands and environmental constraints. The production of Brassica vegetables for the UK market extends from Jersey in the Channel Islands to Fife in Scotland, areas exhibiting very different temperatures and day lengths. An increased understanding of the genetic control of vernalization and flowering will benefit growers throughout these areas. The results will be communicated to others through publication in refereed journals and presentations at scientific meetings and at meetings of ELSA and UK Brassica Research Community. In addition the breeding companies hold open days at which demonstration plots and staff advisers will provide information to Breeders, UK and International vegetable growers and the horticultural press.

Publications

10 25 50
 
Description This Horticulture LINK project used a combined candidate gene and Quantitative Trait Locus (QTL) approach to identify Brassica genes involved in the regulation of heading date in purple sprouting broccoli (PSB). Our approach was informed by the extensive existing understanding of the regulation of flowering time in the related model species, Arabidopsis thaliana

The harvested crop in Brassica oleracea vegetables, such as cauliflower and broccoli, is dependent on the plant making the switch from vegetative to reproductive growth to produce an immature inflorescence.

Working closely with our industrial partners, we have mapped QTL variation for heading date in three divergent populations. These populations have been phenotyped in the greenhouse and in field trials at two UK locations that experience very different winters: Cornwall (relatively mild) and Lincolnshire (relatively cold). The segregation in these populations has allowed us to identify individuals with heading dates ranging from 80 to 320 days with the potential to significantly extend the growing season in the UK. Together we have developed comprehensive linkage maps for these populations that have allowed us to identify 11 QTL affecting heading date. Four of these QTL were mapped in multiple environments in which we phenotyped the populations.
We focussed on five of these QTL in two of the populations and have identified Brassica orthologues of the Arabidopsis flowering time genes, FLOWERING LOCUS C and FRIGIDA among the potential candidate genes for these QTL. Screening a diverse array of Brassica oleracea germplasm we found allelic diversity across crop types that segregated with vernalization response: for example different alleles at one FRIGIDA locus ( BolC.FRI.a) segregate with annual (eg broccoli, autumn cauliflower) or biennial (e.g. Brussels Sprout, Kale) crop type.
In collaboration with our third partner, Weatherquest, we used the phenotypic data from the field trials conducted in geographic locations with contrasting winter climates to improve our understanding of vernalization response to variability in winter climate. We then used these results to predict the impact of possible future climate scenarios on crop scheduling and to identify types of vernalization response which might need to be bred into new varieties for enhanced food security. Final analysis of this data has still to be completed and a manuscript submitted.
Exploitation Route Information will be useful to industrial partners in their breeding program both in Brassica and other species. It will also be of use to those working independently and in collaboration on flowering and other developmental processes in Brassica and other complex genomes
Sectors Agriculture, Food and Drink

 
Description The results and data produced from this project will have impact in a number of ways: • The analysis was conducted using populations of plants that form part of the breeding programs of the industry project partners. • More than 5,000 putative polymorphic markers were identified between the parent lines that can be used to develop both gene-targeted and generic markers • Several hundred SNP based markers were developed and used in the project and these are now being used by the industrial partners • Genomic and Transcriptomic illumina sequence data from 4 parent lines has been shared with the industrial partners • A number of QTLs associated with flowering genes have been identified as affecting flowering time and backcrossed into a common background • Partner awareness was enhanced regarding the impact of weather and climate on field trials and associated impact prevention measures, as was appreciation of how scientific understanding can be deepened through a multi-disciplinary approach
Sector Agriculture, Food and Drink
Impact Types Societal,Economic

 
Description Interview for BBC Radio 4 farming today 
Form Of Engagement Activity A press release, press conference or response to a media enquiry/interview
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Public/other audiences
Results and Impact Radio interview discussimg new short generation broccoli
Year(s) Of Engagement Activity 2017
 
Description Interview for BBC Radio Norfolk Drive time 
Form Of Engagement Activity A press release, press conference or response to a media enquiry/interview
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Public/other audiences
Results and Impact Live radio interview discussing new short generation broccoli
Year(s) Of Engagement Activity 2017
 
Description Presentation at Brassica workshop, PAG 2019 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Invited presentation in Brassica workshop at Plant and Animal Genome conference, 2019 entitled: Dissecting vernalisation: keeping the greens on your plate
Year(s) Of Engagement Activity 2019
 
Description Press article for regional newspaper 
Form Of Engagement Activity A magazine, newsletter or online publication
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Public/other audiences
Results and Impact Article the the Press and Journal following press release about new short generation broccoli
Year(s) Of Engagement Activity 2017
 
Description Talk at Eastern Agritech event 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Industry/Business
Results and Impact Talk to a business audience on developing germplasm for 21st Century Horticultural production
Year(s) Of Engagement Activity 2017
 
Description Talk at Vegetable consultants conference 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Industry/Business
Results and Impact Talk and Q&A session to group of Vegetable consultants who inform framers, growers and producers
Year(s) Of Engagement Activity 2017