Since the late 1980s, Horticultural ResearchInternational (HRI) has undertaken farm

woodlands and forestry research in a wide rangeof disciplines including breeding and genetics,establishment, propagation, physiology (plantand seed), and pests and diseases. The work hasbeen carried out by researchers primarily at EastMalling where research expertise and experiencegained on fruit trees since the 1920s couldreadily be applied to forest tree research, but alsoat Efford and Wellesbourne. The research hasfocused largely on broadleaved trees, includingboth temperate and tropical species, and isfunded by DEFRA, the EC, the ForestryCommission and charitable bodies.

Our research is currently split into fiveinterdisciplinary themes:

1. Tree Genetic Resources including in-situ andex-situ conservation and characterisation.

2. Forest & Woodland Biodiversity includinghabitat and biodiversity assessment,restoration, and creation and genetic diversitystudies including geneflow.

3. Tree Breeding & Improvement involvingconventional selection and crossing ofparental material followed by selection andtrialling of seedlings as well as thedevelopment and use of molecular markersthrough to commercial release.

4. Tree Propagation, Growth & Developmentincluding vegetative cuttings, grafting,micropropagation and seed propagation,physiology and mycorrhizae.

5. Pathology, Pests and Diseases includingbacterial, fungal and viral pathogens,phytoplasmas, pests and integrated cropmanagement strategy.

Current work on improving treesMuch of the improvement work on trees for farmwoodlands and forestry has been undertaken bythe Forestry Commission on conifers,particularly Sitka spruce. With the exception ofpoplar and willow for biomass production, thepotential of broadleaf improvement has untilrecently been relatively neglected.

The British and Irish HardwoodsImprovement Programme (BIHIP), a forum forresearchers and landowners working together on

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Karen Russell describes how seed orchards are being created to produce nativeseed of known origin to improve wild cherry stocks.

Plus tree selected for seed orchard development.

Quarterly Journal of Forestry. 96 (4): 267-270. Russell, K. (2002) Developing seed orchards for Wild Cherry.

the improvement of broadleaf species, hasencouraged tree improvement in ash, birch,chestnut, cherry, oak and walnut throughresearch carried out by various institutesincluding the Oxford Forestry Institute, TheNorthmoor Trust, HRI, and the ForestryCommission. However, there is yet still much tobe done. Each species has a working group thatagrees the improvement approach and seeks theresearch funds to carry this work out. Furtherinformation can be obtained from the BIHIPwebsite: http://bihip.com

The wild cherry programme at HRIThe development of grants to encourage theplanting of woodlands on farmland in the late1980’s triggered DEFRA (formerly MAFF) tosponsor a series of improvement researchprojects at HRI East Malling. Our mainobjective has been to develop vigorous, well-adapted trees with good form and pest anddisease resistances suitable for farm woodlandplantings. Increasingly, we need to ensure thatthese trees are environmentally acceptable, e.g.

of local or native origin,where appropriate.

We chose to focus ourefforts on wild cherry(Prunus avium L.) as it isone of the most attractive,native trees, which cangrow on a wide variety ofsoil types and is particularlysuited to lowland, ex-arablesites. It also has theadvantages of beingunattractive to greysquirrels and fast growing,giving a quality hardwoodtimber after about 70 yearsthat is in demand forfurniture making and ableto substitute for tropicalhardwoods. In addition,HRI could apply itsextensive experience on thegenetic improvement ofsweet cherry, thedomesticated form of wild

cherry, to the wild cherry programme, enablingrapid progress.

The wild cherry improvement programmestarted in 1988 and was described by FionaNicoll in QJF (Nicoll, 1993). At the time, wildcherry did not have a very good reputation, asmany trees were raised from imported seed andwere of unknown origin or quality; many wereprobably of sweet cherry type. As a result, theadaptability of these trees to UK conditions wasoften very poor, with many dying from canker orforming poor trees. The programme at HRIsought to provide genetically reliable material ofknown UK origin to the UK nurseries.

To achieve this we have used the followingapproach. The first step is to identify superiortrees found in our ancient and semi-ancientwoodlands across the UK. Once identified, thegraftwood is collected during the winter monthsby using a long-armed pruning saw or a climber.The graftwood is then taken back to East Mallingwhere it is propagated by grafting on torootstocks, thereby enabling its conservation foruse in the breeding programme. These young

Horticulture Research International

Horticulture Research International (HRI) is the single largestteam of horticultural research and development scientists in theworld with over 550 science and support staff. It is the principalUK organisation tasked with carrying out basic and strategichorticultural research and development and transferring theresults to industry. Its customers include UK research councils,government departments, the EC, overseas agencies, growers,grower-funded levy bodies and the commercial industry.

HRI has five sites, the main ones being at Wellesbourne inWarwickshire, East Malling in Kent and Efford in Hampshire.Wellesbourne focuses on strategic science, annual crops andmushrooms, East Malling on fruit, hardy nursery stock, hops, farmwoodlands and forestry, and Efford on protected crops, nurserystock and soft fruit. Each commodity has a research scientistappointed to provide the link between the science and industry.Karen Russell is the forestry commodity specialist, and is basedat East Malling, Kent.

Further information can be found on the HRI website:http://www.hri.ac.uk

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grafted trees are then tested for various virusesusing herbaceous indicator plants (cucumber andhenbane). Any trees indicating virus symptomswere rejected at this stage to prevent the spreadof viruses and their detrimental effects in theprogramme. Typically about 5% of the treescollected were found to contain viruses. Thehealthy trees, about 100 accessions in all from1989 to 2002, are being used in three ways:

1. They are propagated vegetatively bymicropropagation for multisite trials with aview to choosing the best selections forcommercial release. This approach, simpleand straightforward, is the one we used tocreate the WildstarTM collection, the UK’s firstten wild cherry clones that we released in2000. www.hri.ac.uk/wildstar.

2. The second is to create seed orchards, wheregood accessions are grafted on to rootstocks.The trees of several accessions are plantedout to cross-pollinate each other to producenative seed of known origin and, we hope, ofreasonable quality.

3. The third approach, long term but with thegreatest potential benefits, is to selectindividual trees with desirable characters andto cross pollinate them, with the aim ofcombining these characters in the seedlings.The seedlings are then selected and the mostpromising are propagated clonally andtrialled to identify the best for commercialrelease.

These approaches provide material which issuitable for different circumstances, e.g. cloneswill be desirable for commercial plantings andseedling material for planting in ancientwoodlands.

The rest of this article focuses on thedevelopment and creation of wild cherry seedorchards.

Seed orchardsWild cherry is typically found in woodlandgrowing in small groups or as individual trees.As it frequently reproduces clonally by suckers,the genetic diversity found within a stand is oftenlow, as few of the individuals are genetically

distinct. Stands of good quality with more then 30

genetically distinct individuals in the UK arevery scarce. This, plus predation of seed by birdsand mammals, makes the collection of seed fromquality stands very difficult and it is seldomundertaken. The propagation of trees to createUK seed orchards overcomes these problems andhas the additional advantages that the source ofthe seed and the quality of the parents are known,and dependency on foreign imports is avoided.So far, one seed orchard is producing seed,another has been planted and a third is planned.

Our first seed orchard comprised 17 cloneswhich I’ll describe in a moment. These werepropagated by budding on to Tabel®-Edabrizrootstocks, a French, Prunus cerasus rootstock,by Blackmoors Nursery, Liss, Hampshire inAugust 1997. Tabel® rootstocks were used, asthey not only reduce the vigour of the trees by upto 60% compared to P. avium rootstocks, therebymaking the trees easy to net against birds toreduce seed losses, but they also induce verygood precocity and productivity. The seedorchard was planted at the nursery of WoodlandImprovement & Conservation Limited (WICLtd.), Gloucestershire in May 1998. In total, 290trees were planted at 4m apart in rows and at 5mbetween rows, and on average, there were 15trees of each clone.

Cherry is self-incompatible, i.e. self pollencannot set fruit. A laboratory techniquedeveloped at East Malling was used to determinethe incompatibility group of each clone. Usingthis information, the seed orchard was carefullydesigned so that each tree was surrounded byneighbouring trees with which it was fullycompatible to maximise the chance ofpollination and therefore, fruit set. Seeds werefirst collected from the orchard in 2000 and arenow collected each year, contributing to theprovision of native genuine wild cherry seedlingsto the UK industry. The resulting seedlings areraised and sold by WIC Ltd.

Clones 1 to 4 (Accession numbers 1904,1909, 1912 and 1919 respectively) were chosenfor their good vigour and form in the wild. Theywere selected by Drs Neil Hammatt and FionaNicoll from the first 17 clones collected between

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1989 and 1992 from woodlands in Oxfordshire,Powys, Cumbria and Buckinghamshirerespectively. All are in multisite trials and clones1 and 3 have been used in the breedingprogramme.

Clones 5 and 6 (Seedling numbers F12/1(wild seedling from a seedlot in 1917) and FD1-57-4/13 (seedling of F1/3a) respectively) wereselected by East Malling many years ago forvigour and bacterial canker resistance. Both areperforming well in clonal trials and have beenused as parents in the breeding programme.Clones 1 to 6 have also been selected asWildstarTM clones.

Clones 7 to 15 (Accession numbers 2916,2971, 2973, 3177, 3185, 3183, 3180, 3179 and3181 respectively) were selected by KarenRussell as the best of 9 out of 20 clones of wildcherry collected by her from 14 woodlands inKent, Suffolk, Gloucestershire, East Sussex,Hampshire and Nottinghamshire in the period1994-96. These are currently being evaluated forbacterial canker resistance, vigour and form andall are in trials except clones 11 and 13.

Clones 16 (Accession number 3156) fromLeicestershire and 17 (Accession number 2884)from Yorkshire are recorded by the Tree Registerof the British Isles as the largest and widest(respectively) wild cherry trees in the BritishIsles. These are not in trials.

A second seed orchard of 20 clones(Accession numbers 5005, 3181, 1922, 3146,3180, 3537, 2916, 1918, 5022, 3185, 2474, 1919,3183, 1902, 5009, 1921, 5010, 5007, 1904 and

3543 respectively) collected from the ForestryCommission Zone 405 (South East England),was propagated on to a German rootstock calledGisela 5 (a hybrid of P. cerasus x P. canescens)in March 2001 at HRI East Malling to create thefirst regional wild cherry seed orchard.

The Gisela rootstock was used as it is moredwarfing than Tabel® allowing a more intensiveplanting and the trees are spaced at 2.5m in therow. The clones were collected from woodlandsin Buckinghamshire, East Sussex, Essex,Hertfordshire, Kent, Oxfordshire and Surrey andhave been chosen for their good vigour and form.

As the emphasis was on providing trees on aregional basis, only five are in clonal trials.Again, the incompatibility genotypes of theseclones were established and these were takeninto account when designing the planting so thatall adjacent trees were cross-compatible, whichshould help maximise seed set. The seed orchardwas planted at HRI East Malling in March 2002and should be producing seed in increasingquantities from 2004 onwards. If you areinterested in seed from this orchard, pleasecontact Karen Russell at East Malling.

Twenty clones from Forestry CommissionRegion 30 (South West England, Wales andNorth West England) have been identified with aview to establishing a western local seed orchardin 2002/03.

These seed orchards will provide good, nativeand local planting stock which will complementthe other plant material coming from EastMalling’s breeding programme. It is plannedthat, in the future, regional, clonal seed orchardswill be developed for other important broadleafspecies such as oak, sweet chestnut, ash andwalnut in association with BIHIP. If you know ofany potential plus trees of these species, pleasecontact me at the address below.

REFERENCESNicoll, F. (1993) Quarterly Journal of Forestry,

87, No.3, 187-194.

Karen Russell is the forestry commodityspecialist at Horticulture Research International,East Malling, West Malling, Kent ME19 6BJ.

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Propagation of cherry trees for seed orchard.