Genetic variation and potential genetic resources of several Romanian larch populations

Abstract

RAPD molecular markers and phenotypic growth traits were joined using different genotypes of Larix decidua (Mill.) to analyze genetic variation. Individual samples of vegetative clones were analyzed from Baciu orchard (obtained through a breeding program from regional stands from Romania) and pooled samples from places of origin (regional stands). Based on coefficients of variation for tree height, diameter, and volume, the greatest genetic variation in the orchard was observed at the Gura Humorului and Anina provenances (24.4%, 27.5%, and 14.4% for Gura Humorului and 26.9%, 29.46%, and 15.5% for Anina). In addition, the trees whose origins are Gura Humorului and Anina form the thickest branches. In stands from origin areas, the best performances of growth trait in height were scored in the Valea Popii (33.5 m) and Anina (33.1 m) populations. Stands from Valea Cetatii and Sacele recorded the smallest diameters. Both in orchards and in regional stands the trees with the greatest vigor were those from Gura Humorului and Anina and large variability was noted, which allows efficient selection in order to identify superior trees useful for larch breeding. RAPD analysis illustrated the genetic differences among the larch proveniences and some provenances represented distinct genetic entities, recognizable at the molecular level. The dendrogram indicates the diversity of the genotypes divided into seven groups as were the collection sites. Polled samples of DNA proved to be a valuable tool for determining the phylogenetic relationships in larch provenances. Thus, most populations from regional stands are grouped in the same branch (group) with clones from orchard. The correlation between genetic distance and geographical distance was not significant, with a correlation coefficient of 0.035. In addition, a slight decrease was observed in genetic distance with increase in geographical distance between genotypes.