prilagođeno pretraživanje po punom tekstu

ŠUMARSKI LIST 11-12/2019 str. 34     <-- 34 -->        PDF

country in terms of ecological and silvicultural aspects. Natural distribution ranges of oriental spruce are between 550 and 2400 m and it is widespread in the Eastern Black Sea Region, the center of its distribution areas. On the other hand, the species is dominant at treeline and upper subalpine forest, the elevation of this zone varies between 1800 and 2400 m depending on anthropogenic pressure and local ecological conditions in its natural distribution area (Üçler et al. 200l; Üçler et al. 2018). However, a small number of studies were conducted on genetic variation of oriental spruce. In a study about morphological characters of P. orientalis in Turkey, it was determined that the main reason of seed, cone and wing size variation was ecological differentiation throughout gradients, especially regarding watershed parameters and altitude (Turna 2004). In another study performed in P. orientalis, genetic variation was attempted by using only two enzyme systems (Turna and Yahyaoğlu 2002). Results of genetic monitoring in populations concerning the species were rare. Goncharenko et al. (1996) stated that heterozygosities and genetic diversities of P. orientalis clearly fell below the average.
For sustainable forest health, genetic diversity provides evolutionary potential against a changing environment. As trees are normally the key element of forest ecosystems, their genetic diversity has also special importance. At the same time, it is known that genetic variability is the basis for tree breeding. Thus, the genetic diversity of trees can be seen as the primary factor for forest sustainability and ecosystem stability. Allozymes and molecular markers (Avise 1994; Ouborg 1999) based on DNA can assist in the estimation of genetic diversity, in the development of sustainable forest management practices as genetic, in the determination of genetic structure and diversity of populations (Luo et al. 2005).
Although genetic diversity has been predominantly predicted by DNA markers over the last decade, allozyme still remain a preferred marker due to a number of advantages. These indicators, which demonstrate the genetic diversity between individuals and populations, are necessary for the development of effective strategies for sustainable management and protection (Crawford 1989; Hamrick et al. 1992; Vicario et al. 1995; Luo et al. 2005; Radu et al. 2014). In addition, the allozyme markers are useful for monitoring the genetic changes in the evolutionary process and for identifying geographic variation models that are useful in gene conservation.
Monitoring the geographical genetic variation within natural populations of P. orientalis in Turkey consists of the aim of the present study. In this way, it can be provided a contribution to the characterization of genetic resources and to the practical measures for in-situ conservation of genetic variation. A check on genetic erosion and inbreeding will help to detect genetic loads and thus to avoid destabilization following the use of unqualified forest reproductive material.
In the scope of this study, seeds were collected from 10 different populations (to be at least 20 trees per population) of oriental spruce. Haploid endosperms and diploid embryos of the air-dry seeds of oriental spruce were used in isoenzyme analysis. Sampling in 10 populations of this species a smaller amount of material was available so that routinely only 60 samples per stand were genotyped, i.e. endosperm and embryo of each of 30 seeds.  The geographical coordinates of selected populations of oriental spruce naturally grown in Turkey (Table 1) and distribution on the map, determined by using management plans belong to the country, (Figure 1) are given in below. The geographic distribution of sampled populations allowed an evaluation of overall genetic diversity of this species in Turkey.