Resistance and susceptibility in interactions between apple and woolly aphid
Godfrey, C.J. (2024) Resistance and susceptibility in interactions between apple and woolly aphid. Doctoral thesis, Harper Adams University.
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Cindayniah Godfrey Corrected PhD Thesis C Godfrey 18241800 (1).pdf Download (3MB) | Preview |
Abstract
The woolly apple aphid (Eriosoma lanigerum Hausmann; WAA) is a widespread sap-sucking pest of Malus × domestica (Borkh.) which has spread from its native range in northeast America worldwide, feeding on all parts of the tree above and belowground year-round. There are four known WAA resistance genes, three of which have been used in rootstock breeding programmes to great commercial success. Reports have emerged of WAA feeding on rootstocks deriving from these three genes, highlighting a need to identify novel resistance sources and to improve genetic resources for existing resistance genes to increase development and release of durably resistant rootstocks. We identified SNP markers significantly linked to the Er2 gene and a region of the genome in which this gene may lie. We also suggest accessions of the crab apple species Malus floribunda as likely novel resistance sources for further investigation. The loss of host-alternation outside of its native range is thought to also indicate exclusive asexual reproduction. We found genetic variation within the UK, and when compared to ten sites abroad, suggestion of sexual reproduction at some sampling locations. We also found varied population structure with some isolated clonal populations. Estimations of individual and population growth metrics suggested reduced performance when feeding on WAA-resistant rootstocks, although traditional metrics were not suitable for a fragile, slow-growing species such as WAA. The findings of this project have been used throughout to inform apple growers of best practice for monitoring and managing WAA.
| Item Type: | Thesis (Doctoral) |
|---|---|
| Divisions: | Agriculture and Environment (from 1.08.20) |
| Depositing User: | Mrs Rachael Giles |
| Date Deposited: | 01 Nov 2024 15:15 |
| Last Modified: | 01 Nov 2024 15:15 |
| URI: | https://hau.repository.guildhe.ac.uk/id/eprint/18141 |
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