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Technical guidelines for genetic conservation and use Wild and pear M sylvestris/Pyrus pyraster B. Richard Stephan1, Iris Wagner2 and Jochen Kleinschmit3 1 Institut für Forstgenetik und Forstpflanzenzüchtung, Grosshansdorf, Germany EUFORGEN 2 Forschungsinstitut Pro Arbore, Dresden, Germany 3 Niedersächs. Forstliche Versuchsanstalt, Stauffenberg-Escherode, Germany These Technical Guidelines are intended to assist those who cherish the valuable wild apple and pear genepool and its inheritance, through conserving valuable seed sources or use in practical forestry. The focus is on conserving the genetic diversity of the at the European scale. The recommendations provided in this module should be regarded as a commonly agreed basis to be complemented and further developed in local, national or regional conditions. The Guidelines are based on the available knowledge of the species and on widely accepted methods for the conservation of forest genetic resources.

Biology and ecology

Wild apple (Malus sylvestris (L.) Mill.) and wild pear (Pyrus pyraster (L.) Burgsd.) belong to the family . They are insect pollinated and are both quite rare species. Wild apple trees have expanded crowns and often look like bush- es. They can grow up to 10 m tall with trunk diameters of 23-45 cm and can live 80-100 years. Under good growing condi- tions, wild pear trees have a remarkably slender form with a characteristic rising crown. In less favourable conditions they show other characteristic growth forms, such as one-sided or extremely low crowns. Trees can reach heights of 22 m with clean trunks up to 10 m, and diameters of 45-80 cm (maximum 130) at an age of 80-150 years (maxi- mum 250). P. pyraster is able to MalusWild apple and pearMalus sylvestris sylvestris Pyrus pyrasterWild apple and pearMalus sylvestris Py Pyrus

grow on very dry sites due to its Distribution Importance and use tap roots. Owing to their weak compet- itive ability, wild apple and wild Both species are native in most Hybridization with pear exist mostly at the edge of European countries, and they grown for fruit production is sup- forests, in farmland hedges or on occur in a scattered distribution posed to be very common, very extreme, marginal sites. pattern as single individuals or in making it very difficult to identify Without competition by other small groups. pure wild fruit trees. In the past, tree species, P. pyraster would only morphological characters have a wide physiological range were used for identifica- and physiological optimum. Wild tion purposes. Two main pear can grow on almost all soils, traits to characterize M. except the most acidic. Best sylvestris are hairiness growth occurs on fresh, calcar- of the undersides of eous soils. With competition, leaves and fruit width. the species is often Important traits to displaced to more characterize P. pyraster extreme sites (very are fruit width and fruit dry or wet). The pre- and leaf form. ferred niches for wild Wild apple timber is of pear are close to the low economic value, dry or wet edges of the whereas that of wild pear forest. P. pyraster favours is highly valued and has South and West facing slopes. many potential uses. The ecology of M. sylvestris is similar to that of P. pyraster, except that wild apple is more indifferent to soil type. The preferred niches are on the wet edge of the forest. Both species have extremely high light requirements and do not tolerate competitive pressure well, especially by beech. There are well known occurrences of wild fruit trees in river floodplain forests where both native species (apple and pear) are associated. Pyrusus pyrasterWild apple and pyrasterpearMalus sylvestris Pyrus pyrasterWild apple andMal pearMalus sylv

Genetic knowledge more than 100 individuals of M. has yet to be performed. Only a sylvestris from northwestern few experiences of applying PCR regions of Germany, partially based methods to M. sylvestris The genetic variation and struc- rejects this hypothesis since are available. ture of M. sylvestris and P. species-specific alleles have pyraster is not yet known in detail been identified. These alleles and requires extensive study. have been found at relatively The two species show great phe- high frequencies, indicating that notypic variation and it is the introgression of M. sylvestris assumed that various ecological genes into the M. ✕ domestica types can be distinguished due genepool has rarely or not to the large natural distribution occurred in the past at all since area. M. ✕ domestica has been grown. Genetic analyses have been Different genepools have also undertaken mainly on domesti- been identified by analysing cated varieties of apple. Malus is native M. sylvestris in Belgium. a of the northern temper- There is little genetic inform- ate zone with 25-35 (47) species ation known about P. pyraster. that are difficult to identify due to Working with iso- the lack of distinguishing traits. enzymes in pear is This is supposed to be largely more difficult than the result of introgression for apple. A between cultivated varieties and compari- wild species. Isoenzyme analy- son of 183 ses at the species level in Malus clones of are limited, but are a common P. pyraster method in identification. collected in Until recently, this method had northwestern failed to distinguish M. sylvestris Germany was (in the past represented only by a made with wild few single trees), M. pumila, M. pears growing on typ- orientalis, M. asiatica and M. ical species sites and sieversii from each other or these with cultivars. The closely related wild species from comparison revealed M. ✕ domestica. The level of differences between the genetic diversity was found to be three pear groups in phenotype very high in all these species and frequencies of two isoenzymes. very similar to that found in the Genetic analyses based on DNA domesticated apple. It has been markers may provide better suggested that these are not dis- information regarding the imme- tinct species, but have formed diate ancestor of cultivated one large population extending apple and pear, and regarding from western China to Europe. the influence of hybridization, but Recent research, investigating the research using DNA markers ylvestrislus Pyrus pyraster sylvestrisWild apple and pearMalus sylvestris Pyrus pyraster PyruWild apple and pea

Threats to Guidelines for genetic genetic diversity conservation and use

Genetic resources of wild apple The natural situation of and wild pear are seriously these rare fruit tree endangered, for the following species and their occur- reasons: rence as single individu- Rare occurrence and a narrow als or in small groups, genetic base cause genetic drift restricts the possibilities due to small numbers of mother for implementing in situ trees and large distances conservation strategies. For between adult trees; both species, the establishment Natural regeneration is not of ex situ conservation seed guaranteed and, if it occurs, it is orchards seems to be the most endangered by grazing; suitable and efficient conserva- Hybridization with cultivated tion measure to undertake. forms of apple and pear is con- Natural regeneration should sidered to be a major obstacle. be supplemented by planting of Recent investigations in apple seedlings originating from seed indicate that hybridization has orchards. This method extends not been that rampant as the genetic base of regeneration, expected. which is important for future Useful identifi- adaptability. cation keys have Grafting is not difficult and been developed, seed orchards can be relatively but are not satisfac- easily established. A minimum of tory (distinguishing 50 clones per seed orchard and characters may not be region should be selected. New developed consistently breeding populations can be on an individual tree restored when individual speci- level); and mens, scattered over a large, but Uncontrolled seed trans- ecologically similar area, are col- fer. In EU countries wild lected and planted apple and wild pear are not together in the included under national seed orchard. legislation for forest reproductive materi- al. Therefore, seed of unknown origin is used for afforesta- tion purposes in the landscape and along highways. MalusWild apple and pearMalus sylvestris sylvestris Pyrus pyrasterWild apple and pearMalus sylves

Distribution range of wild apple.

Distribution range of wild pear. estrisPyrus Pyrus pyrasterWild apple and pearpyrasterMalus sylvestris Pyrus pyrasterWild apple andM pea

EUFORGEN

These Technical Guidelines were Selected bibliography produced by members of the EUFORGEN Noble Hardwoods Network. The objective of the Net- Coart, E., X. Vekemans, M.J.M. Smulders, I. Wagner, J. Van Huylenbroeck, E. Van Bockstaele and I. Roldan-Ruiz. 2003. Genetic variation in the endan- work is to identify minimum genet- gered wild apple (Malus sylvestris (L.) Mill.) in Belgium as revealed by AFLP ic conservation requirements in and microsatellite markers. Molecular Ecology (12: 845-857). the long term in Europe, in order Vornam, B. and K. Gebhardt. 2000. PCR-based markers reveal genetic identi- to reduce the overall conserva- ty and diversity in subset collections of wild and cultivated apple. Acta tion cost and to improve the qual- Hort. 530:463-467. ity of standards in each country. Wagner, I. 1996. Summarizing of morphological characters and their properties to distinguish wild and culture forms of the European apple (Malus) and pear (Pyrus) tree [in German]. Mitt. Dtsch. Dendrol. Ges. 82:87-108. Wagner, I. 1998. Evaluation of wild forms of apple and pear [in German]. Pp. 68-82 in Wild pear, Pyrus pyraster (L.) Burgsd. (J. Kleinschmit, B. Soppa and U. Fellenberg, editors). Schrift. Forstl. Fak. Univ. Göttingen und Nieders. Forstl. Vers.anst., Vol. 125. (Sauerländer’s Verlag, Frankfurt am Citation: Stephan B. R., I.Wagner Main) and J.Kleinschmit. 2003. EUFOR- Wagner, I. and N.F. Weeden. 2000. Isozymes in Malus sylvestris, Malus domes- GEN Technical Guidelines for tica and in related Malus species. Acta Hort. 538:51-56. genetic conservation and use for Wagner, I., H.P. Schmitt, W. Maurer and U. Tabel. 2003. Isozyme polymorphism wild apple and pear (Malus and genetic structure of Malus sylvestris (L.) Mill. in western areas of sylvestris and Pyrus pyraster). Germany with respect to Malus x domestica Borkh. (manuscript). International Genetic Resources Institute, Rome, Italy. The distribution maps were compiled by members of the EUFORGEN 6 pages. Noble Hardwoods Network based on an earlier maps published by (i) Kutzelnigg, H., 1995: Pyrus. In: Scholz, H. (Hrsg.), 1995: Gustav Hegi. Illus- trierte Flora von Mitteleuropa. Band IV, Teil 2B (2. Aufl.). Blackwell, Berlin. Drawings: Pyrus pyraster, Giovanna S. 278-288); (ii) Meusel H., Jäger E. Weinert E. 1965. Vergleichende Chorologie der Zentraleuropäischen Flora. Veb Gustav Fischer Verlag, Bernetti. © IPGRI, 2003. Jena, 1. Karten, pp. 258 (iii) Wagner, I., 1995: Identifikation von Wildapfel (Malus sylvestris (L.) MILL.) und Wildbirne (Pyrus pyraster (L.) BURGSD.) Voraussetzung zur Generhaltung des einheimischen Wildobstes. ISBN 92-9043-604-2 Forstarchiv 66: 39-47.

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