Crop Genetic Diversity - A Plant Health Solution
Charlotte Allender, Warwick Genetic Resource Unit
Managing and preventing outbreaks of pests and diseases on our crops is a financially and environmentally expensive activity. Globally, crop losses due to pests and diseases may reduce yields by up to 40%. The application of chemical controls (including pesticides and fungicides) is an additional cost to farmers, and these substances can have unwanted environmental impacts. Finding another solution to the issue of managing crop pest and diseases is essential in order to support more sustainable food production and to improve to global food security.
Genetic variation within crops is an important resource to use to improve the health of our crops. Pest and disease resistances are valuable traits, and may be found in less utilised parts of the crop genepool, for example in populations of wild relatives of crops and in landraces (traditional varieties developed through many generations of selection by farmers). Crop genebanks like the UK Vegetable Genebank have the role of conserving crop genepool diversity to ensure it remains available for research and breeding. Valuable diversity is at risk of loss through habitat destruction for wild populations and historical changes to farming practices. Diverse landraces have been replaced by commercial varieties (which benefit crop production). Some of these landraces have been lost altogether, others only exist in genebank collections. Whilst many of these are not suited to modern, highly mechanised farming practices, they may harbour genes conferring resistance to plant pests and diseases.
The UK Vegetable Genebank manages a collection of around 14,000 seed samples of vegetable crops. Opened in 1980, our seed has been used around the world for research and crop improvement, often to screen to look for new sources of resistance to diseases such as black rot and clubroot, and pests such as carrot root fly and diamond back moth. Once a resistance trait has been identified, it is then possible to cross it into breeding lines for new varieties. It can be helpful to screen for DNA markers associated with the resistance trait in order to follow it more efficiently across generations in the breeding process.
You can hear from some researchers about how they use crop diversity in their research with the aim of improving resistance to pests and diseases.