Mapping and analysis of genetic loci controlling quality traits in broccoli

Abstract

The consumption of Brassica vegetables in the UK has increased over the past 10 years. In particular, the demand for fresh broccoli has increased in line with increased public awareness of the nutritional profile and health benefits associated with this crop. Broccoli has an unpredictable shelf life attributed primarily to genetic and environmental variation. Differing supply-chain components exacerbate the situation. Most leafy vegetables are supplied on a three-day delivery cycle; broccoli requires a 2-day delivery cycle. Improving broccoli shelf life by 1 day would benefit the supply chain considerably. The rapid post-harvest senescence of broccoli heads is characterised by visible phenotypic changes such as head yellowing, browning and reduced turgor. However, these changes in organoleptic quality are preceded by a decline in the nutritional status of the heads. Since post-harvest yellowing is not visible until the later stages of head senescence, consumers may be eating broccoli of inferior nutritional status. At WHRI we have developed a unique ‘broccoli x broccoli’ doubled haploid mapping population derived from the F1 of the cross between a poor performing line (yellow in 2 days) with a line that stayed green for more than 4 days at 16°C. The fixed mapping population captures the complete range of diversity in days to yellowing and has been scored for quality traits in field trails at WHRI over 4 growing seasons. Data for shelf life traits including bud yellowing are being used to identify putative QTL positions on our framework linkage map. We are extending this work to investigate the nutritional status of the broccoli head at harvest and how the metabolite profile changes through storage. This project will deliver valuable breeding resources that will benefit the supply chain and ultimately the consumer