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Value of Variety

'Variety' in vegetables has considerable commercial value, in terms of providing a range of products, which grow at different locations and times of the year. It includes cultivars that may be resistant to particular pests or diseases or may be able to grow in conditions that are particularly challenging.

‘Variety’ is obviously genetically-determined and Warwick researchers are developing resources and technology to identify useful attributes in vegetables that may be incorporated into the cultivars of the future.

Warwick Genetic Resources Unit (the UK vegetable gene bank) has a globally significant collection of almost 14,000 samples of important vegetable crops. The collections consist of a wide range of small-seeded, mainly outbreeding vegetables and associated wild taxa including onion, leek, celery, vegetable brassicas, carrot, lettuce and radish. Charlotte Allender, the GRU manager and her team explained the work of the gene bank, including facilities for the regeneration of seed stocks and seed packaging and storage. Wild relatives of crop species are an important part of the Warwick GRU collections, and visitors were able to see living examples of close relatives of crops such as carrot and lettuce and hear about how they can contribute to crop improvement programmes.

The extensive base collections held in Warwick GRU provided the ideal starting point to select smaller representative core collections to be characterised by researchers in the leafy vegetables component of the Defra-funded Vegetable Genetic Improvement Network (VeGIN) project. Graham Teakle, Peter Walley and colleagues were available to discuss their work screening for tolerance to pests including aphids, cabbage root fly, diamond back moth, resistance to virus diseases, and investigating the genetic control of nitrogen use efficiency/ nitrate accumulation. The plant material has been genetically characterised, allowing us to link variation in the plants DNA to the control of these characteristics. One of the key targets for breeding is disease resistance.

John Clarkson and his team explained how they have developed reliable screening methods for various fungal plant pathogens utilising brassica and onion diversity sets developed as part of the Defra-funded VeGIN and Oil Seed Rape Genetic Improvement Network (OReGIN) projects. Resistance to Sclerotinia disease which causes losses in oilseed rape, lettuce, carrot and a wide variety of other horticultural crops has been identified in B. napus as well as in some wild brassica species. Good resistance to basal rot caused by Fusarium oxysporum has also been identified within the onion diversity set which will be exploited in a new BBSRC Horticulture and Potato Initiative (HAPI) project with East Malling Research, Nickerson-Zwaan and HDC. Next generation sequencing will be employed to understand the genetic basis of the resistance and to develop associated markers which can be used to develop resistant onion cultivars. A similar approach is being used in a BBSRC-funded PhD CASE project with Elsoms Seeds where genotyped parsnip lines are being screened for resistance to canker pathogens. In all these projects we are aiming to combine a good understanding of plant pathogen biology with the latest genome-based technologies and genetic resources to provide durable and effective disease resistance in different crops.

Eric Holub explained the use, at Warwick, of the latest DNA mapping techniques to allow British farmers to grow one of the UK’s favourite foods. The navy bean (Phaseolus vulgaris) – also known as haricot bean– commonly ends up on our plates with a tomato-based sauce as baked beans. It is a staple of the British diet - we consume hundreds of millions of cans of baked beans in a year. However, every single baked bean we eat is grown outside of the UK. Eric's group have launched a research project at the Crop Centre to use DNA sequencing technology to begin mapping the genes governing the traits that are needed for the navy bean to thrive in the UK climate. Further information
Building a better British baked bean news feature

A further expression of ‘variety’ is in terms of differences in flavour/taste. This is well illustrated by the wide variety of chilli peppers that are available currently and continue to be bred. Andrew Jukes’ main interests are evaluating pesticides and bio-pesticides for control of insects and pathogens although he is also recognised as an authority on chilli pepper analysis, having tested several peppers which have been officially recognised as the worlds’ hottest. He explained his work at the Open Afternoon where there was a display of a range of chilli peppers and posters supplied by Sea Spring Seeds (Dorset).
BBC breakfast Chilli Hot Stuff news feature