26 Breeding and conservation of black poplar (Populus nigra) gene resources in Turkey F. Toplu With black poplar in native stands urkey is characterized by widely are hybrid poplars and 60 000 ha con- threatened in Turkey, action to varying climatic and topographic sist of various clones of black poplar. manage and conserve the genetic Tconditions which result in a Black poplar provides about 57 percent resources of this valuable species broad diversity of forest ecosystems, of Turkey’s 3.5 million cubic metres of is showing promising results. species and within-species variation. annual poplar wood production. Poplar European black poplar (Populus nigra) wood industries – particularly furniture, has a wide distribution in Turkey and has packaging, particleboard, plywood and been cultivated by farmers on private matches – have developed very quickly lands for centuries. It makes consider- in recent years and mainly use the wood able contributions to both the rural and of hybrid poplars. On the other hand, the national economy. However, with more than 80 percent of black poplar urban expansion and mismanagement wood (1.75 million cubic metres) is used of natural resources in rural areas, it is as roundwood for rural construction and one of the most threatened tree species for the daily needs of rural people. in native stands in Turkey – as it is also in Europe. Ferit Toplu is with the Poplar and Fast-Growing Turkey has approximately 130 000 ha Forest Trees Research Institute, Yahyakaptan, of poplar plantations, of which 70 000 ha Black poplar plantation Izmit-Kocaeli, Turkey. around agricultural fields, Yozgat, Central Anatolia region OPLU F. T F. Unasylva 221, Vol. 56, 2005 2 Black poplar field clone trial, Ankara, Central Anatolia In some parts of central, eastern and southeastern Turkey, black poplar is cul- tivated in field, roadside and riparian plantations using traditional methods. Where land is reserved for agriculture, row plantations can protect arable land and produce wood for local needs. In the T F. OPLU main river basins, about 100 000 km of waterways are suitable for gallery plan- tations, i.e. one to three rows of poplars Resources Programme (EUFORGEN). also capable of vegetative regeneration. planted on both sides of the waterway Under these programmes, five previ- Its seeds are disseminated by wind and (Semizoglu, 1979); some gallery planta- ously unknown natural populations of water, have short viability and need spe- tion projects are under way supervised black poplar have been identified in the cific soil and humidity conditions for by the Ministry of Forestry. Eastern Anatolia region. germination. Regeneration is generally Poplars are also of ecological poor within long-established stands. importance as centres for biodiversity. BIOLOGY, ECOLOGY AND The most widely cultivated clones of A large number of threatened and DISTRIBUTION black poplar in Turkey are P. nigra var. common species are associated with The natural range of European black italica, used mostly in the western part or dependent on poplars, particularly poplar, Populus nigra, includes most of the country, and Populus usbekis­ in floodplain forests, which are among of Western Europe (with the exception tanica var. afghanica, which is more the most diverse ecosystems in Europe of Scandinavia, Ireland and Scotland), widespread. Both have characteristic (Rotach, 2003). Thus the monitoring and Ukraine, the Russian Federation, parts narrow, pyramidal crowns. conservation of the genetic resources of North Africa and Asia Minor, and of black poplar in riparian ecosystems northern Islamic Republic of Iran. Black SELECTION AND BREEDING is of major significance, not only for poplar usually forms local populations Black poplar is used in breeding pro- the natural control of flooding, but also by colonizing open areas on alluvial grammes in many parts of the world: because the river borders harbour great soils through seeds, cuttings or root 63 percent of the poplar cultivars used biodiversity. fragments. Its distribution extends from in forest plantations descend from black This article describes efforts made in isolated trees to large blocks of pure or poplar. To improve the quantity and qual- recent years in the breeding, conser- mixed stands. Individual trees may live ity of wood harvested from poplar planta- vation, management and utilization of up to 400 years. Almost 40 percent of tions in Turkey, classical breeding pro- black poplar genetic resources in Turkey. black poplars are grown in line planta- grammes with Populus deltoides, native This work has included the establish- tions along canals and stream banks and P. nigra and Populus × euramericana ment of clone banks and clonal trials in around irrigable fields. are in progress for commercial release of nurseries and fields and the identifica- Black poplar trees are dioecious, with the most productive hybrid clones. Use- tion of black poplar clones with high separate male and female individuals. ful traits of parents such as fast growth, growth performance and adaptability They grow fast and reach the reproduc- desired wood quality and resistance to to different ecological conditions. In tive stage at approximately ten years of frost can be combined in a hybrid, and addition, ex situ and in situ conservation age. In the early spring (early April in some clones are selected from intra- or programmes for black poplar have been Turkey), male and female trees produce interspecific crossings. in progress in Turkey under the frame- flowers clustered in pendulous catkins. Domestic black poplar provenances work of the European Forest Genetic Black poplar is wind pollinated and is are included in the breeding programme Unasylva 221, Vol. 56, 2005 2 Natural distribution of black poplar Black (Populus nigra) Sea in Turkey Melet Kelkit Ankara Munzur Pülümür Karasu Mediterranean Sea Locations of clone banks and field trials in Turkey Finally, gene introgression (i.e. move- Locality Region Clone banks and field trials ment of genes between genetically dis- Harran Southeastern Anatolia Nursery clone trial tinct populations) from cultivated clones First selection clone trial and other poplar species is a potential Tunceli Eastern Anatolia First selection clone trial threat to the integrity of black poplar, Erzurum Eastern Anatolia Clone bank because only a few clones are widely Nursery clone trial First selection clone trial cultivated and these contribute mark- Ankara Central Anatolia Clone bank edly to the pollen and seed pools in Nursery clone trial native stands. This risk concerns not only First selection clone trial introduced hybrids, but also pure black Kutahya Inner Aegean Nursery clone trial First selection clone trial poplar varieties with wide distribution Second selection clone trial such as P. nigra var. italica. Izmit Marmara Clone bank Therefore, it has been necessary to take action to conserve and manage Turkey’s because of their adaptability to continen- THREATS TO GENETIC RESOURCES valuable black poplar heritage. Clone tal conditions. They are widely planted in Three main factors threaten the genetic banks in nurseries and clonal field tri- eastern European countries for domestic resources of European black poplar als have been established in a range of use and for soil protection and afforesta- (Lefèvre et al., 2001). First, human activ- climatic zones (see Table). Considerable tion in polluted industrial zones. Black ities alter riparian ecosystems through- progress has been made in the conserva- poplar is hybridized with P. deltoides and out the species’ distribution area. Native tion and identification of black poplar other introduced poplar species such as poplar stands are being displaced by clones with high growth performance Populus maximowiczii and Populus tri­ agriculture and floodplain areas are sub- and adaptability to different ecological chocarpa which provide adaptability to ject to urbanization. Regulation of floods conditions. various soil and climate conditions, root- has altered the regeneration capacity of ing ability, high resistance to bacterial the species and favoured the succession CONSERVATION OF BLACK canker caused by Xanthomonas populi of poplar stands by hardwood forests. POPLAR IN TURKEY and fair resistance to Marssonina brun­ Although regeneration may be success- In situ conservation nea and to poplar mosaic virus (Cagelli ful locally, some regions of Europe Conservation programmes in Turkey, and Lefèvre, 1995). have witnessed significant reductions undertaken within the framework of the Populus nigra × P. nigra hybrids and in native black poplar populations or European Forest Genetic Resources Pro- P. deltoides × P. nigra hybrids are being their complete disappearance. gramme (EUFORGEN), focus on in situ selected through nursery and field clone Second, the autochthonous black pop- conservation. trials in Turkey. Successful clones are lar resources have been overexploited The ultimate aim of in situ conservation registered nationally and internationally for the use of wood and wood products of a species is to maintain broad genetic by the International Poplar Commission and faster-growing hybrid poplars have diversity so that the species can retain (IPC). been planted to replace them. its potential to adapt to changes in the Unasylva 221, Vol. 56, 2005 2 environment. When the objective is to conserve genetic diversity and maximize the adaptive potential of the species, dynamic conservation is preferable. This can be achieved through in situ conserva-