Diversity and breeding potential of poplar species in China

Abstract

The genus Populus is composed of many species with an impressive variety of growth characteristics. Nevertheless, this abundant natural offering has been only partially utilized to date with the objective of promoting poplar breeding and cultivation. Following an old tradition, more or less inflexible production systems are mainly keyed to a few high-yielding P. x euramericana and P. x interamericana clones in most countries. Consequently, considerable economic failures have to be accepted repeatedly as a result of serious calamities.China ranks among the countries characterized by an exceptionally multifarious indigenous flora. Based on ample genetic variation, poplar species were able to settle in divergent habitats and to conserve the ability to survive and reproduce over long periods owing to adaptation processes. The diversity is concentrated, above all, in the subtropical mountain regions of southwest China. Comprehensive studies of the genus Populus in the southern and eastern mountain chains of the Qinghai-Tibet Plateau turned out to be particularly impressive; 3 sections, 17 species and 15 varieties have been recorded and taxonomically classified there. They grow at altitudes between 1500 m and 4300 m above sea level. Many of these poplar sources are notable for their remarkable site adaptation even in harsh conditions and also for their fast and vigorous growth.Species expected to be suitable for international breeding and cultivation objectives in the near future are presented in a general way. The necessarily subjective selection is based on the state of available knowledge mainly about site requirements, environmental importance, growth characteristics, regeneration ability, silvicultural behaviour, yield estimation and wood utilization. In particular, the following species are characterized in the paper in an abridged fashion: P. cathayana, P. davidiana, P. euphratica, P. simonii, P. szechuunica, P. ussuriensis and P. yunnanensis.The potential of poplars in China is considered to be instrumental in expanding and stimulating poplar breeding activities worldwide. Measures to be specified in the paper are considered important and could be implemented on the basis of a close and confident co-operation with Chinese colleagues and institutes relevant to the subject and under the umbrella of the International Poplar Commission.Key words: poplar, tradition, calamities, China, genetic variation, promising species, characteristics, breeding priorities Le genre Populus comprend plusieurs espbces dkmontrant une trbs grande variCt6 de caractCristiques de croissance. Neanmoins, cette abondance naturelle n'a Ct C que partiellement utilisCe B ce jour dans le cadre de la reproduction et de la culture du peuplier. Suivant une vieille tradition, des systkmes plus ou moins inflexibles de production sont principalement 21 la base du peu de clones B haut rendement de P. x euramericana et de P. x interamericana dans la plupart des pays. En conskquence, des Cchecs Cconomiques consid6rables dCcoulant de calamitCs sCrieuses...

Net NH4 + and NO3 − fluxes, and expression of NH4 + and NO3 − transporter genes in roots of Populus simonii after acclimation to moderate salinity

“…This species is an important poplar species in the northwestern area of China that grows in drought and saline conditions (Weisgerber and Han 2001). The noninvasive micro-test technique (NMT) was used to study the net NH 4 ?…”

Moderate drought did not affect the effectiveness of ethylenediurea (EDU) in protecting Populus cathayana from ambient ozone

“…In this study, Populus cathayana was selected because it is a native species distributed in the North China (Weisgerber and Han, 2000) and has been confirmed to be sensitive to O 3 with typical O 3 symptoms and significantly lower photosynthesis and biomass at AOT40 of 20 ppm.h in previous studies (Gao F. unpublished results). We propose that EDU protects the P. cathayana from ambient O 3 at well-watered condition, but does not protect under drought stress due to reduced stomatal O 3 flux.…”

Population Genetic Survey of Populus cathayana Originating From Southeastern Qinghai-Tibetan Plateau of China Based on SSR Markers

“…Due to its unique geographical and geological historical factors, variable terrain and complex climatic conditions, the Qinghai-Tibetan Plateau, especially its southern and eastern mountain areas, has abundant and special resources of the genus Populus, and it is regarded as the natural distribution and variation center of genus Populus in China (WEISGERBER and HAN, 2001;YU, 2003). Many Populus species, mainly of Sect.…”