Forest genetic resources / Projects / China
Conservation of native poplarsConservation of the remaining genetic resources of native poplar species, concentrating on P. nigra L., P. simonii Carr. and the related P. pseudosimonii Kitag., the only fast-growing indigenous species adapted to the extreme climatic conditions and the poor soils of the region. Whenever possible, this unique genetic material is conserved in situ. When this option was not possible, samples of genetic diversity were explored, collected, propagated and stored in ex situ collections, genebanks and arboreta.
Populus nigra is naturally distributed in China only in two river valleys of the Altay region, Xinjiang. These natural stands are threatened by over-cutting, conversion to farmland and overgrazing, causing severe environmental problems. These changes in land use and the land degradation also prevent the natural regeneration of the species. Natural regeneration still occurs on a limited scale, but is further damaged by livestock grazing. The ¿009¿ Project has initiated emergency ex situ conservation and the use of native P. nigra in its poplar breeding programme. However, more urgent action is needed, especially political decisions towards in situ conservation. The protection of remaining stands and natural regeneration on the riverbanks should be a priority for the local forest managers and authorities.
Populus simonii, an important species of poplar in North China, is widelydistributed across 18 provinces (in Chinese) and autonomous regions of China, with more than 2 000 years of cultivation history. Since 1949, P. simonii has been used as the major tree species in establishing 700 000 ha of plantations. As a native tree species, P. simonii has been grown in many paces in North China and has played a vital role in speeding up the greening and afforestation of land and barren hills. With strong cross-compatibility, P. simonii became the first parent of poplar cross-breeding in China in the 1960s, with several well performing crossbred progenies. Since the 1980s, however, the resource base of P. simonii has decreased dramatically, and natural forest stands are becoming rare due to natural disasters and deforestation.
Field investigations studied P. simonii not only in natural stands across northern China, but also in plantations (an innovation). Collections of P. simonii were established from material collected during these investigations, and set up a P. simonii genebank with 645 lots of cuttings selected from seven provinces in the Three-North Region. In addition, 321 superior individuals were selected for seed collection and comparative tests in 1992. Among the trees propagated from superior parent clones, six showed good growth and scored well for resistance to frost and drought. (after 6 years)Activities related to the establishment of in situ and ex situ genebanks and improvement of P. simonii were also conducted by the project. These included studies on growth, resistance, phenology and phenotypic variations of various provenances of P. simonii; intraspecific crossing among different provenance of P. simonii; and interspecific controlled crosses between P. simonii and other poplar species. Good phenotypic sources were selected from in situ and ex situ genebanks as parent material for cross-breeding, from which F1 seedlings were planted in comparative trials in arid areas. Apoplar breeding strategy , customized to the conditions of North China in general, and the Korqin Lands in particular, was defined and implemented in participating project outstations and collaborating institutions. A number of unique and promising combinations, especially P. deltoides x P. simonii and P. simonii x P. simonii, were obtained and are still currently under observation.At the same time the project also reviewed research activities on P. simonii in China. In particular, studies on P. simonii yielded interesting results. Organized by the project, a number of scientific research papers written by poplar experts were published, including Collection of scientific research papers on P. simonii in northern China, which provides a theoretical basis for future research work on P. simonii. In January 2002, a booklet entitled<i>Populus simonii</i> in North China (in Chinese, with a summary in English), compiling and summarizing previously scattered information on the species' biology, distribution, use and cultivation, was published by the project.
FAO. 2002. Technical project review document. Rome.