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Development of novel plant breeding and biological strategies for the protection of parsnips and carrots from free living plant parasitic nematodes

Primary supervisor: Dr Matthew Back, Department of Agriculture and Environment

Secondary supervisor: Dr Charlotte Allender, University of Warwick

Project title: Development of novel plant breeding and biological strategies for the protection of parsnips and carrots from free living plant parasitic nematodes

Project description:

Being able to produce sufficient food to feed a growing population, whilst reducing undesirable environmental impacts of farming, is one of the major challenges of the 21st Century. Reducing loss and wastage caused by pests and diseases is a necessary part of the solution; host plant resistance and biological approaches to managing crops pests and diseases offer alternatives to synthetic pesticides as a solution.

British parsnips and carrots are popular, nutritious root vegetables, available in our shops for 11 and 12 months of the year respectively. Both crops are produced in light, sandy soils in various counties of England and Scotland. Other than aphid-transmitted viruses, the British Carrot Growers Association regard free-living nematodes (FLN) as the most important threat to production. In the last national surveys of FLN in carrots and parsnips (Boag, 1979 and 1980), the main FLN genera found were stubby root (Trichodorus and Paratrichodorus spp.), root lesion (Pratylenchus spp.), pin (Paratylenchus spp.) and needle (Longidorus spp.) nematodes. Although the majority of these genera are ectoparasites, feeding externally, the root lesion nematode is a migratory endoparasite that creates invasions tracts through roots often leading to secondary infections. Meanwhile, ectoparasite feeding can result in reduced water and nutrient uptake and distortion of the roots known as ‘fanging’. Up until recently, FLN were managed through the application of the nematicide Vydate (oxamyl). However, Vydate was withdrawn in December 2020, leaving carrot and parsnip growers with limited options for managing FLN other than the application of a garlic-based product (Nemguard). A recent AHDB review project (FV 477), highlighting the lack of control options, identified arbuscular mycorrhizal fungi as an alternative control strategy with a high potential of success.

The aim of this project is to evaluate available carrot and parsnip genetic resources for resistance against the most damaging FLN genera and investigate whether mycorrhiza treatment can be integrated to improve tolerance to nematode feeding. Moreover, the synergy between promising varieties/lines and mycorrhiza will be evaluated in order to develop a robust crop protection approach. The project will utilise a range of techniques including phenotyping, transcriptomics and microscopy. It is anticipated that a small survey will be conducted to identify commonly occurring FLN found in carrot and parsnip rotations. Experiments will be conducted in controlled environments and in the field to evaluate the performance of accessions and mycorrhiza treatments. Finally, the mechanisms behind observed nematode suppression will be investigated.

BBSRC Strategic Research Priority: Sustainable Agriculture and Food: Plant and Crop Science & Animal health and Welfare & Microbial Food Safety

Contact: Dr Matthew Back, Harper Adams University