Approccio molecolare per la scomposizione dei caratteri adattativi in Populus nigra L.: costruzione di una mappa genetica basata su marcatori AFLP, SBR e SNP
Author(s)
Gaudet, Muriel
Date Issued
April 10, 2006
Type
Doctoral Thesis
Abstract
The genus Populus has been accepted as model for fundamental research on trees. Populus trichocarpa is in fact the first tree to have its whole genome sequenced. In addition, poplars are forest trees of considerable commercial importance for their fast growth. Among the native European poplars, Populus nigra L. (black poplar) is a tree of ecological and economic interest. It is a pioneer species of riparian ecosystems but it is threatened with extinction because of the loss of its natural habitat. Populus niga also plays a central role in breeding programs and has contributed to many successful interspecific hybrids (Populus deltoides x Populus nigra = Populus x canadensis). For an effective protection and use of the remaining Populus nigra genetic resources, a better knowledge of Populus nigra genome is needed. In this context, the main objective of this study is the construction of a highly informative genetic map in Populus nigra. For this purpose, two Populus nigra genotypes, with divergent phenotypes, from natural Italian populations were selected as parents of a controlled intra-specific cross, which generated a mapping pedigree of 165 individuals. AFLP, SSR and SNP markers were used to genotype 92 F1 individuals for mapping analysis. The map construction was based on the pseudo-testcross strategy. In this way, two maps were obtained, one for each parent. The map of the female parent included 368 markers (274 AFLPs, 91 SSRs and 3 SNPs) and spanned 2789 cM with 20 linkage groups, whereas the male parent map, including 317 markers (205 AFLPs, 106 SSRs and 5 SNPs), spanned 2816 cM with 23 main linkage groups. Sex morphological trait was also mapped on the linkage group XIX on the male parent. The generated maps are rich in SSRs also shared among the published Populus maps. The alignment with the Populus trichocarpa physical map and the Populus genetic maps from other studies allowed the identification of the 19 haploid chromosomes of Populus. The comparison of these Populus nigra maps with the other Populus maps validated the accuracy of locus ordering and showed an important synteny and co-linearity of the genomes. A framework map for each parent was also constructed to allow the perspective of mapping QTLs for phenology and growth. The possible applications of these maps in comparative mapping, QTL analysis and marker-assisted selection are discussed.
Additional information
Dottorato di ricerca Ecologia forestale
File(s)![Thumbnail Image]()
Name
mgaudet_tesid.pdf
Size
5.4 MB
Format
Adobe PDF
Checksum (MD5)
052556a980eb44565a7e479907c71e92