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ŠUMARSKI LIST 7-8/2021 str. 49     <-- 49 -->        PDF

the second discriminant function explained 29.0%. The discriminant analysis showed that the trees from eight natural populations of Scots pine in Turkey cannot be clearly separated.
The conducted research established significant variability of the morphological characteristics of Scots pine populations in Turkey. Statistically significant differences between the trees within and between populations were confirmed for all studied characteristics, except for the sheath length. In general, the morphological traits of needles appeared to be a useful tool for estimating pine species variability (Irvine et al. 1998; Niinemets et al. 2001; Pensa et al. 2004; Pravdin 1969; ¯elawski and Niwiñski 1966; Paule 1971; Urbaniak et al. 2003; Androsiuk et al. 2011; Jasiñska et al. 2014; Poljak et al. 2020).
It is well known that phenotypic differences among populations are often a result of the environmental distances between populations (Dewoody et al. 2015; Poljak et al. 2012, 2014, 2018; Zebec et al. 2014). This is because the distribution of plant species depends highly on their competitive abilities to respond to environmental factors (Schoettle and Rochelle 2000). In some cases, morphological variability can be related to the altitude (Friend and Woodward 1990; Schoettle and Rochelle 2000; Poljak et al. 2015, 2018, 2020; Zebec et al. 2015). Specific gradient i.e. changes in morphological variability related to the change in altitude have been reported for Scots pine populations in Turkey (Turna and Güney 2009) and Croatia (Poljak et al. 2020). The mentioned authors stated that populations from lower altitudes had smaller cones as compared to the populations from higher altitudes. The present study revealed that needle length, needle width and the ratio of needle length to needle width significantly vary depending on altitude. In general, we reveled that populations from lower elevations were characterized with lager needles than the populations from higher altitudes. This may be related to the capacity of trees to adapt to environmental variation, which causes morphological changes in plant species and also facilitates the successful survival of plants subjected to new environmental conditions (Abrams 1990; Ellsworth and Reich 1992; Kubiske and Abrams 1992; Lei and Lechowicz 1997; Teklehaimanot et al. 1998; Aranda et al. 2001). Similarly, needle length of P. roxburghii Sarg. from the northwestern Indian Himalayas significantly correlated with altitude (Tiwari et al. 2013). Furthermore, differences in the morphological and anatomical properties of cones, needles and seeds along altitudinal and longitudinal gradients were reported in four populations of P. brutia Ten. by Dangasuk and Panetsos (2004). In addition, Xu et al. (2016) noted that needle length and the ratio of needle length to fascicle sheath length showed clinal variation in response to latitudinal and altitudinal gradients in P. yunnanensis Franch.
The results of the cluster and discriminant analysis did not confirmed divergence between the populations from different habitat zones from Turkey. Moreover, microclimatic effects that depended on existing geological structures, even when very short distances are considered, can result with significant interpopulation variability of Scots pine populations in Turkey (Ergül Bozkurt 2017). According to Kantarcı (2005), vicinities in which Bolu, Kastamonu, Ankara and Eskiºehir are found share similar ecological conditions. However, samples collected from these localities were not distinctly separated from the rest of the samples examined via multivariate statistical analysis.
According to reports within the Flora of Turkey and the East Aegean Islands (Davis et al. 1984), only P. sylvestris var. hamata is naturally distributed in Turkey. However, Farjon (2008) noted that P. sylvestris var. sylvestris and P. sylvestris var. hamata are naturally distributed in Turkey. In addition, Kandemir and Mataracı (2018), described a new variety of P. sylvestris, var. elicinii Kandemir and Mataracı, based on needle length from a Sürmene-Çamburnu population (TS). However, average, minimum, and maximum values of needle length of the TS population are closely related to Artvin-Arhavi (AH) and Kastamonu-Taºköprü (KT) populations. Additionally, present findings inferred from multivariate statistical analysis did not support the separation of TS population. In general, our result does not support the validity of different subspecies and variates of Scots pine in Turkey. In addition, Jasiñska et al. (2014) reported that the morphological needle and cone characteristics of P. sylvestris varied among the populations of Iberia, Anatolia, the Balkans, and Crimea. Nevertheless, their results did not confirm the existence of P. sylvestris subsp. sylvestris and P. sylvestris subsp. hamata.
We observed significant phenotypic differentiation of studied populations of P. sylvestris in Turkey. Those populations represent the valuable relict genetic resources that are of high conservation priority. To confirm the conclusions reached on the variability of the Scots pine populations obtained by morphometric methods, the research also needs to be extended to molecular methods.
We would like to express our special appreciation to staff of Forest Enterprises of Ardahan, Artvin (Arhavi, Hopa), Trabzon (Sürmene), Giresun (Espiye), Kastamonu (Taºköprü), Bolu (Karacasu-Aladağ), Ankara (Çamlıdere) and Eskiºehir (Çatacık) for their kind assistance with the field studies.