tailieunhanh - Báo cáo lâm nghiệp: "rigins and diversity of the Portuguese Landrace of Eucalyptus globulus"

Tuyển tập các báo cáo nghiên cứu về lâm nghiệp được đăng trên tạp chí lâm nghiệp Original article đề tài: Origins and diversity of the Portuguese Landrace of Eucalyptus globulus. | Ann. For. Sci. 64 2007 639-647 INRA EDP Sciences 2007 DOI forest 2007042 Available online at Original article Origins and diversity of the Portuguese Landrace of Eucalyptus globulus Jules S. FREEMANa Cristina . Marques0 Victor CAR0CHAb Nuno BoRRALHOb Brad M. PoTTSa René E. Vaillancourt a School of Plant Science and Cooperative Research Centre for Forestry University of Tasmania Private Bag 55 Hobart Tasmania 7001 Australia b RAIZ Centro de Investigacao Florestal Quinta de S. Francisco Apartado 15 Aveiro Portugal Received 21 July 2006 accepted 7 February 2007 Abstract - The Portuguese Landrace of Eucalyptus globulus is of unknown origin with the earliest plantings of this tree species dating back to the early 19th century. In Portugal it is currently a major seed source for plantations and is also used in breeding programs. Eucalyptus globulus is native to south-eastern Australia. The substantial genetic differentiation of chloroplast and nuclear DNA markers between different native geographic races of this species allowed us to uncover the Australian origins of the Portuguese Landrace and to study its genetic diversity. To achieve this we sequenced a highly polymorphic region of chloroplast DNA from 47 Portuguese Landrace individuals and genotyped 34 of these using seven nuclear microsatellites. We compared these individuals to those in a database comprising chloroplast DNA sequence profiles from 292 native trees and seven nuclear microsatellites from 372 native trees. The majority of the Portuguese Landrace samples had closest affinities in both marker systems to native trees from south-eastern Tasmania but some had affinities to trees from south-eastern Victoria. The discrepancies in the affinities indicated by chloroplast versus nuclear DNA markers could be explained by inter-race hybridisation after introduction. The genetic diversity in the Portuguese Landrace was less than that found in native E. globulus at the species level .