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UK National Fruit Collections

NATIONAL FRUIT COLLECTIONS ACCESSIONS POLICY

This document describes the rationale used to determine the content of the DEFRA National Fruit Collections (NFCs) and the methods by which they are conserved. A clear accessions policy has been defined in order to ensure that the selection of germplasm maintained in the Collections fulfils specific objectives and reflects the needs of users. The accessions policy guides the curators in selecting high priority material for accession into the Collections and in identifying low priority material for de-accession.

The collections, particularly the Malus collection, include varieties from a wide variety of locations in the UK and beyond. Approximately half of the varieties conserved in the Malus collection originated in the UK. In addition, varieties with interesting or unusual morphological and phenological characteristics have been selected for conservation. On this basis, it is assumed that the collections adequately represent genetic diversity occurring in the target crops.

Objectives of maintaining the Collections

1. To conserve the genetic diversity present in cultivated temperate fruit genera, in particular that which has been grown in or originated in the UK, or is of actual or potential value to horticulture in the UK.
2. To facilitate the supply of fruit germplasm samples to scientific researchers, commercial interests and the public.

Needs of the main users

One of the most important functions of the NFCs is that they act as living herbaria for Plant Variety Rights (PVR) testing. Submitted varieties are tested against existing described varieties. The NFCs must therefore contain a wide selection of described varieties. The varieties required include those named by The International Union for the Protection of New Varieties of Plants (UPOV) characterisation lists, all varieties that have been granted rights in the UK and commercially important varieties that it is possible to grow in UK. Many of the newer apple varieties have been obtained by mutation of existing varieties, rather than cross-pollination. These mutation varieties are of equal importance to PVR testing as sexually derived varieties.

Plant breeders form an important set of users. In the UK, most fruit breeding takes place at Horticulture Research International, East Malling. The most valuable genetic resources to breeders at HRI are accessions of cultivars that originated in the UK and have been verified against descriptions in historical documents, scientific reports or nursery catalogues. Foreign cultivars of known merit are also of use. Material from the NFCs is mainly used by breeders in crosses with advanced selections to introduce a particular character missing from the selection.

A wide range of scientific studies utilise the Collections, many of which take place at HRI (East Malling and Wellesbourne). Recent projects have included research into the genetic basis of disease resistance and fruit firmness. The needs of these users are less predictable than for PVR and breeders, however in general germplasm that has been authenticated against varietal descriptions in peer reviewed literature is of most value. Close contact must be maintained with scientific users in order to obtain feedback on whether the NFCs are meeting their needs.

Users in industry require variability within traits such as storage potential and disease resistance. Therefore the needs of these users are met by maintaining a selection of varieties that show diversity in all traits. Currently, it is assumed that variability in these traits occurs within the Collections. A continuing program of characterisation is underway to quantify the morphological variation.

Brogdale Horticultural Trust provides gardeners and the general public with propagating material from the Collections. Many of these users are interested in varieties traditionally grown in their region, for projects such as the creation of community orchards. To meet the needs of amateur users, the Collections should contain varieties of a wide range of provenances within the U.K.

Method of conservation

The National Fruit Collections are maintained in a field genebank. This method of maintenance is used for several reasons;

1. The varieties of fruit existing today have been selected by a process of domestication that has taken thousands of years. Fruit cultivars cannot be propagated by seed, and therefore have to be maintained by vegetative propagation. A seed genebank could be used to conserve genetic diversity of cultivated fruit, but would not be suitable for conserving fruit varieties.
2. Maintaining the Collections as mature trees facilitates the distribution of graft- and bud-wood, and samples of leaf, bark, pollen and fruit. If the accessions were maintained only by micropropagation or cryopreservation, then it would take several years to recover material such as pollen and fruit. In addition, mature trees form a valuable resource for breeders because sufficient flowers are available to make a large number of crosses.
3. The Collections also act as a living herbarium against which samples of unknown varieties may be compared.

Collection security

For the majority of species in the NFC, two plants are maintained per accession. Most accessions of vine are represented by three replicates of five plants each, which is the minimum number required for trial vinifications. If one of the individual plants within an accession dies, it is replaced by repropagating material from another plant of the same accession. Field genebanks are vulnerable to environmental stresses, therefore added security is provided by back up collections. A database has been created of specialist orchards in the UK that contain rare apple varieties. Owners of such collections should be encouraged to grow varieties that are currently known at only very few sites.

Priorities for new accessions

Varieties required for PVR testing that are not currently contained within the collections have a high priority. Varieties that have been granted PVR are routinely accessed. UK varieties with associated published descriptions not currently contained within the collections are a high priority for accession. In particular, the UK Network for Malus project has identified more than two hundred apple cultivars exist in a very small number of private collections but not in the NFC. The first step in accessing this type of material is a preliminary verification from fruit samples. Newly received material is held in an observation plot before full accession into the NFC. The status of collections of wild relatives at the NFC is currently unresolved.

Priorities for de-accession

The Collections currently contain a number of accessions that are incorrectly named, shown in the catalogue as 'Bloggs Pippin (false)'. These varieties will be investigated, and if they have no apparently interesting or useful characteristics they form a high priority for de-accession. A programme of verification and characterisation of material accessed since the early 1970's is in progress. This will assist in identifying duplicates in the collections (particularly apple). Varieties that failed PVR testing, such as King Jonagold and Highwood will be de-accessed. Foreign varieties that are represented in overseas collections, which have not been used in the UK historically, commercially or scientifically may also be de-accessed.

Main users of the NFC are consulted before material is de-accessed.

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nfc@ic.ac.uk

Last updated 23 November 2001