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Controlling supply, quality and waste in brassica vegetable crops: understanding the causes of variation in maturity of purple sporouting broccoli (PSB) - HL0186LFV

Executive Summary - Final report

The vegetable Brassica industry requires reliable uniform cropping and harvest season extension. Growers are looking for high commercial quality throughout the year, so there is a real need for varieties with a more robust response to variable weather patterns to avoid peaks and troughs in crop production. How different varieties respond to vernalization has a big effect on when and how they mature. Identifying alleles for characters which control this trait and learning more about the differential temperature response of individual varieties will improve the grower’s
ability to reliably predict harvest periods.

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. This project utilized unique Purple Sprouting Broccoli(PSB) breeding material, which was produced independently by Elsoms Seeds Ltd, to explore the genetic basis of variation in the vernalization response in Brassica.

Using a high throughput, fluorescent-labelled marker system genetic maps were constructed from three populations of PSB that encompass a wide range of variation in vernalization response. Simultaneously field trials were conducted in two major Brassica growing areas (Lincolnshire and Cornwall) to identify QTL for heading date and vernalization response under two different growing regimes. QTL analysis identified 3-5 QTL per population that are common to both sites or that are present only under one set of growing conditions. From comparative analysis with the reference plant Arabidopsis, the regions of the B. oleracea genome underlying the QTL show synteny with regions containing members of Arabidopsis gene families known to be involved in the control of vernalization and flowering time. Weather data recorded close to each trial site showed clear differences in the temperature profiles between the two sites. Previous studies have shown that different cauliflower varieties respond to a range of cardinal temperatures for vernalization with an optimum of up to 12oC. The observed variation in heading date and flowering time in the PSB populations between the two field sites suggest marked differences between the parental genotypes and within the mapping populations in response to the growing conditions.

This feasibility LINK project has demonstrated that Brassica oleracea germplasm contains considerable genetic diversity for vernalization response and has the potential to be bred to produce varieties for growing under a range of climatic conditions. Using the outputs from this project we have developed a new research proposal to address key questions about the impact of climate patterns on the availability of UK produced quality Brassica vegetables. We will build on these initial findings and translate them into knowledge and tools that will have a major impact in Brassica breeding. Elucidation of the genetic basis mechanism controlling vernalization response in Brassica will allow us to identify varieties that are more or less responsive to different periods of cold and hence more or less susceptible to the fluctuations of the British weather.
Project Documents
• Abstract : HL0186 Abstract   (19k)
Time-Scale and Cost
From: 2007

To: 2008

Contractor / Funded Organisations
Elsoms Seeds Ltd, John Innes Centre (BBSRC)
Food Chain              
Food Quality              
Fields of Study