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Genetic variability in insect populations in relation to host plant specificity - HH1766SFV

Description
Herbivorous insects are pests of many agricultural and horticultural crops. The effective control of these insects is essential for the sustainability of a competitive industry. Many control strategies are targeted at individual species or groups of species and take little or no account of the variation that might occur within the species. The overall objective of this project is to provide a measure of the genetic variability within the population of an aphid species and how this is associated with its host plant specificity. The cabbage aphid, Brevicoryne brassicae, and its host plants within the Cruciferae, including many Brassica crops, will be the model system studied. The results of this study will have three primary uses. Firstly they will inform crop improvement programmes on the variability within parasite species to which resistance is being sought. Secondly, they will provide background strategic information for those developing integrated pest management strategies on the diversity within species, the relevance of alternative crop host plants in the management of pests and an indication of the spatial scale over which pest forecasts might operate. Thirdly, an understanding and knowledge of the diversity within species is essential for the preservation of biodiversity. The methodologies developed in this programme will provide the tools to measure the impact of the introduction of genetically modified plants on the biodiversity of target and non-target species. This information is all vital for the development of environmentally benign and sustainable control of pests that is essential for the maintenance of a competitive industry and the reduction in pesticide use.

During the first two years of the project it has become apparent that:
i) Genetic diversity within Brevicoryne brassicae is extremely low.
ii) Host plant utilisation has no structuring effect upon genetic diversity in this species. Consequently, it has been agreed that the remainder of the project will focus on the lettuce root aphid (Pemphigus bursarius) and its hosts within the Compositae, including lettuce as a second meodel system.
As part of a one year additional funding opportunity,we will assay aphid morphs for changes in gene expression during important shifts in the life cycle, as a preliminary insight into real adaptive physiological adaptations involved in aphid survival.

As part of a one year additional funding opportunity,we will assay aphid morphs for changes in gene expression during important shifts in the life cycle, as a preliminary insight into real adaptive physiological adaptations involved in aphid survival.
Objective
The overall objective within four years is to provide a measure of the genotypic variation in one aphid species and indicate how this is associated with host plant specificity. To achieve this the specific objectives are to:1. Molecular methodology. Identify and refine the most appropriate molecular methods for the study to enable the rapid genotyping of large numbers of samples of individual aphids.2. Molecular variability within UK. Determine the extent of variability within populations of one aphid species within the UK.3. Molecular variability between crop types. Quantify the differentiation between populations of one aphid species on different plant types.4. Biological specificity on crop types. Quantify the virulence and performance of genotyped clones of one aphid species on different plant types.5. Determine changes in gene expression profile and characterise some selected genes involved during host shift phases of the aphid life cycle.

Project Documents
• Final Report : Genetic variability in insect populations in relation to host plant specificity   (285k)
Time-Scale and Cost
From: 2000

To: 2004

Cost: £673,854
Contractor / Funded Organisations
Horticulture Research International
Keywords
Biotechnology              
Brassicas              
Breeding              
Farming              
Horticulture              
Organic Farming              
Pest Control              
Vegetables