___

• 36
• Friedman and Adams (1985) 12.5 16 Isozymes (21) 21
• El-Kassaby et al. (1989) Pinus sylvestris Pinus sylvestris
• Pseudotsuga menziesii 12.5 2 Isozymes (11) 49
• Adams et al. (1997) Picea abies Quercus robur 13.2 4.5 nSSRs (6) 70
• Buiteveld et al. (2001) Pinus pinaster
• Pinus thunbergii 11.8 0.5 RAPDs (28) 2
• Goto et al. (2002) Pinus brutia Pinus pinaster 11.2 4 nSSRs (3) Kaya et al. (2006)
• Fernandes et al. (2008) Pinus sylvestris
• Pinus koraiensis 13.7 1 nSSRs (13) 25
• Feng et al. (2010) Pinus brutia 17.8 cpSSRs (6) 39 Present study earlier seed orchard studies in forest trees. Moreover, another study based on allozymes and carried out in another seed orchard of the same species within the same region showed 85.7% pollen contamination (Kaya et al.,
• 2006). The pollen contamination level in the present seed
• orchard was much lower than that reported by Kaya et al.
• (2006). The high contamination level of the latter orchard
• reported by Kaya et al. (2006) may be due to its relatively
• young age (11 years old) as well as to 2 neighboring stands
• located about 100 m away from the studied orchard. Harju
• and Nikkanen (1996) estimated 48% pollen contamination
• in a P. sylvestris seed orchard isolated from other stands
• by about 2 km. Pakkanen et al. (2000) in Picea abies
• and Slavov et al. (2005a) in Pseudotsuga menziesii also
• estimated pollen contamination levels in 3 different years
• and the mean contamination level was 70% and 35.3%,
• respectively. Although contaminant pollen generally has
• a lower breeding value than pollen originating from the
• seed orchard clones, the assessment of genetic quality of
• incoming pollen from outside stands is puzzling. If the
• genes are introduced to a seed orchard via alien pollen that
• originated from populations maladapted to the habitat of
• the offspring establishment, gene flow may reduce the
• fitness of the offspring and seriously affect the survival and
• production of operational plantations.
• Pollen contamination level depends on several factors,
• including the amounts of pollen production inside an
• orchard, the flowering synchronization among the orchard
• clones, the timing and duration of female cone receptivity
• of orchard clones relative to other pollen sources, the level
• of pollen production in neighboring stands, and annual
• weather variation (such as wind direction, temperature,
• and rainfall) during the period of male conelet maturation
• and female conelet receptivity (Harju and Muona, 1989;
• Burczyk et al., 2004b; Alizoti et al., 2010). The data related
• to annual climatic conditions prevailing over the last 10
• years in the seed orchard area show that the mean monthly
• temperatures during the flowering season (2006) had not
• significantly deviated for the last 10 years, including the
• year of the flowering. However, the last 10 years’ means
• of monthly precipitations were unstable during the
• flowering seasons of the involved years, ranging from
• 258 mm (2008) to 1410.20 mm (2012). Total annual
• precipitation of rain in the year of flowering (2006) was
• above average (1159.52 mm) (www.tutiempo.net). The
• timing of the flowering season for individual species varies
• from year to year, depending on weather conditions, and
• this may partly confound the relationship between pollen
• accumulation rates and climate conditions in individual
• months in the flowering year, as a given calendar month
• may in some years cover a larger or smaller proportion
• of the flowering season of a given plant species (Nielsen
• et al. 2010). Many reports about pollen contamination in seed orchards have demonstrated that gene flow can be extensive, and there is evidence that the pollen of widely distributed forest tree species can disperse over large distances, from 10 up to 100 km (Burczyk et al., 2004a).
• In this study, the per-mother-tree proportion of progenies
• fertilized by the pollen coming from the clones of the seed
• orchard ranged from 50% to 90%. This means that some
• factors such as flowering phenology and clonal fertility
• variation might cause pollination variation among mother
• trees. Additionally, earlier and later receptive trees in seed
• orchards are more prone to being fertilized by alien pollens
• (Harju and Nikkanen, 1996; Slavov et al., 2005a).
• Although pollen contamination might increase genetic
• diversity in a seed orchard crop, it also seriously reduces
• the potential genetic gain to be obtained from the seed of
• the orchard (Fast et al., 1986). In addition, outside gene
• flow might reduce or improve the adaptability of produced
• seeds. The background pollination estimated in this study
• appears to have caused losses in the predicted genetic
• gains from the clonal seed orchard crop by 20%. Plomion
• et al. (2001) reported the pollen contamination rate as 36%
• in the P. pinaster polycross seed orchard and estimated that
• genetic gain was reduced by 18.25%. Kaya et al. (2006)
• reported that the expected genetic gain in P. brutia seed
• orchard crops was reduced by at least 43% due to a high
• level of pollen contamination. Flowering asymmetry and
• variations of pollen production among trees within the
• orchard were probably the main factors that cause pollen
• contamination and thereby reduction in the genetic gain.
• In order to reduce pollen contamination and thus
• increase the genetic gain obtained from the seed orchard
• crops, some precautions should be taken. First, the
• establishment of seed orchards in areas well isolated from
• putative contamination sources can be one of the most
• practical methods. Second, using a greater number of
• ramets in wider areas might increase pollen production in
• the orchard. Third, selection of clones that synchronize well
• and produce abundant and almost equal numbers of male
• and female conelets might also increase pollen production
• in the orchard. Another approach is the reorganization of
• the seed orchard environment. If there are trees belonging
• to natural (wild) populations, as was the case in the present
• study, the removal of these trees could help reducing
• pollen contamination. Fast-growing and adaptable species
• to the region (i.e. Pinus pinea, Eucalyptus sp., Cupressus
• sp.) can also be planted to establish an isolation zone
• around the seed orchard. It may be worthwhile to apply
• pollen management strategies such as cone stimulation
• (for example, use of gibberellins to increase reproductive
• output), use of controlled pollination whenever possible,
• and supplemental mass pollination to increase the genetic
• quality of the seeds produced (Caron and Leblanc, 1992;
• Kaya et al., 2006; Stoehr et al., 2006; Fernandes et al., 2008). Ecol 12: 2087–2097.
• Dellaporta SL, Wood J, Hicks JB (1983). A plant DNA minipreparation: version II. Plant Mol Biol Rep 1: 19–21.
• Dzialuk A, Burczyk J (2004). PCR-multiplex of six chloroplast microsatellites for population studies and genetic typing in Pinus sylvestris. Silvae Genet 53: 246–248.
• Dzialuk A, Muchewicz E, Boratynski A, Montserrat JM, Boratynska K, Burczyk J (2009). Genetic variation of Pinus uncinata (Pinaceae) in the Pyrenees determined with cpSSR markers. Plant Syst Evol 277: 197–205.
• El-Kassaby YA, Rudin D, Yazdani R (1989). Levels of outcrossing and contamination in two Pinus sylvestris L. seed orchards in northern Sweden. Scand J For Res 4: 41–49.
• Excoffier L, Laval G, Schneider S (2005). ARLEQUIN Ver 3.0: An integrated software package for population genetics data analysis. Evol Bioinform Online 1: 47–50.
• Fady B, Semerci H, Vendramin GG (2003). EUFORGEN Technical Guidelines for Genetic Conservation and Use for Aleppo Pine (Pinus halepensis) and Brutia Pine (Pinus brutia). Rome, Italy: International Plant Genetic Resources Institute.
• Fast W, Dancik BP, Bower RC (1986). Mating system and pollen contamination in a Douglas-fir clone bank. Can J For Res 16: 1314–1319.
• Feng FJ, Sui X, Chen MM, Zhao D, Han SJ, Li MH (2010). Mode of pollen spread in clonal seed orchard of Pinus koraiensis. J Biophysical Chem 1: 33–39.
• Fernandes L, Rocheta M, Cordeiro J, Pereira S, Gerber S, Oliveira MM, Ribeiro MM (2008). Genetic variation, mating patterns and gene flow in a Pinus pinaster Aiton clonal seed orchard. Ann For Sci 65: 706.
• Friedman ST, Adams WT (1985). Estimation of gene flow into two seed orchards of loblolly pine (Pinus taeda L.). Theor Appl Genet 69: 609–615.
• Goto S, Miyahara F, Ide Y (2002). Identification of the male parents of half-sib progeny from Japanese black pine (Pinus thunbergii Parl.) clonal seed orchard using RAPD markers. Breeding Science 52: 71–77.
• Goto S, Watanabe A, Miyahara F, Mori Y (2005). Reproductive success of pollen derived from selected and non-selected sources and its impact on the performance of crops in a nematode-resistant Japanese black pine seed orchard. Silvae Genet 54: 69–76.
• Harju A, Muona O (1989). Background pollination in Pinus sylvestris seed orchards. Scand J For Res 4: 513–520.
• Harju AM, Nikkanen T (1996). Reproductive success of orchard and nonorchard pollens during different stages of pollen shedding in a Scots pine seed orchard. Can J For Res 26: 1096–1102.
• İçgen Y, Kaya Z, Çengel B, Velioğlu E, Öztürk H, Önde S (2006). Potential impact of forest management and tree improvement on genetic diversity of Turkish red pine (Pinus brutia Ten.) plantations in Turkey. For Ecol Manag 225: 328–336.
• Jones ME, Shepherd M, Henry R, Delves A (2008). Pollen flow in Eucalyptus grandis determined by paternity analysis using microsatellite markers. Tree Genet Genomes 4: 37–47.
• Kandemir GE, Kandemir İ, Kaya Z (2004). Genetic variation in Turkish red pine (Pinus brutia Ten.) seed stands as determined by RAPD markers. Silvae Genet 53: 169–175.
• Kang KS, Lindgren D, Mullin TJ (2004). Fertility variation, genetic relatedness, and their impacts on gene diversity of seeds from a seed orchard of Pinus thunbergii. Silvae Genet 53: 202–206.
• Kang KS, Harju AM, Lindgren D, Nikkanen T, Almqvist C, Suh GU (2001). Variation in effective number of clones in seed orchards. New For 21: 17–33.
• Kaya N, Işık K (2010). Genetic identification of clones and the genetic structure of seed crops in a Pinus brutia seed orchard. Turk J Agric For 34: 127–134.
• Kaya N, Isik K, Adams WT (2006). Mating system and pollen contamination in a Pinus brutia seed orchard. New For 31: 409–416.
• Kimura M, Crow JM (1978). Effect of overall phenotypic selection on genetic change at individual loci. P Natl Acad Sci USA 75: 6168–6171.
• Kurt Y, Bilgen B, Kaya N, Işık K (2011). Genetic comparison of Pinus brutia Ten. populations from different elevations by RAPD markers. Notulae Botanicae Horti Agrobotanici Cluj-Napoca 39: 299–304.
• Kurt Y, Gonzalez-Martinez SC, Alia R, Işık K (2012). Genetic differentiation in Pinus brutia Ten. using molecular markers and quantitative traits: the role of altitude. Ann For Sci 69: 345–351.
• Lise Y, Kaya Z, Işık F, Sabuncu R, Kandemir İ, Önde S (2007). The impact of over-exploitation on the genetic structure of Turkish red pine (Pinus brutia Ten.) populations determined by RAPD markers. Silva Fenn 41: 211–220.
• Mirov NT (1967). The Genus Pinus. New York, NY, USA: The Ronald Press Company.
• Moriguchi Y, Prescher F, Lindgren D (2008). Optimum lifetime for Swedish Picea abies seed orchards. New For 35: 147–157.
• Ne’eman G, Trabaud L (2000). Ecology, Biogeography and Management of Pinus halepensis and P. brutia Forest Ecosystems in the Mediterranean Basin. Leiden, the Netherlands: Backhuys Publishers.
• Nei M (1987). Molecular Evolutionary Genetics. New York, NY, USA: Columbia University Press.
• Nielsen AN, Moller PF, Giesecke T, Stavngaard B, Fontana SL, Bradshaw RHW (2010). The effect of climate conditions on inter-annual flowering variability monitored by pollen traps below the canopy in Draved Forest, Denmark. Veget Hist Archaeobot 19: 309–323.
• OGM (2012). Türkiye Orman Varlığı-2012. Ankara, Turkey: T.C. Orman ve Su İşleri Bakanlığı, Orman Genel Müdürlüğü, Orman İdaresi ve Planlama Dairesi Başkanlığı Yayın No.: 85 (in Turkish).
• Pakkanen A, Nikkanen T, Pulkkinen P (2000). Annual variation in pollen contamination and outcrossing in a Picea abies seed orchard. Scand J For Res 15: 399–404.
• Paule L, Lindgren D, Yazdani R (1993). Allozyme frequencies, outcrossing rate and pollen contamination in Picea abies seed orchards. Scand J For Res 8: 8–17.
• Peakall R, Smouse PE (2006). GENALEX 6: Genetic Analysis in Excel. Population genetic software for teaching and research. Mol Ecol Notes 6: 288–295.
• Petit RJ, Mousadik A, Pons O (1998). Identifying populations for conservation on the basis of genetic markers. Conserv Biol 12: 844–855.
• Plomion C, LeProvost G, Pot D, Vendramin G, Gerber S, Decroocq S, Brach J, Raffin A, Pastuszka P (2001). Pollen contamination in a maritime pine polycross seed orchard and certification of improved seeds using chloroplast microsatellites. Can J For Res 31: 1816–1825.
• Scalfi M, Piotti A, Rossi M, Piovani P (2009). Genetic variability of Italian southern Scots pine (Pinus sylvestris L.) populations: the rear edge of the range. Eur J Forest Res 128: 377–386.
• Shannon CE, Weaver W (1949). The Mathematical Theory of Communication. Champaign, IL, USA: University of Illinois Press.
• Slavov GT, Howe GT, Adams WT (2005a). Pollen contamination and mating patterns in a Douglas-fir seed orchard as measured by simple sequence repeat markers. Can J For Res 35: 1592–1603.
• Slavov GT, Howe GT, Gyaourova AV, Birkes DS, Adams WT (2005b). Estimating pollen flow using SSR markers and paternity exclusion: accounting for mistyping. Mol Ecol 14: 3109–3121.
• Slavov GT, Howe GT, Yakovlev I, Edwards KJ, Krutovskii KV, Tuskan GA, Carlson JE, Strauss SH, Adams WT (2004). Highly variable SSR markers in Douglas-fir: Mendelian inheritance and map locations. Theor Appl Genet 108: 873–880.
• Smith DB, Adams WT (1983). Measuring pollen contamination in clonal seed orchards with the aid of genetic markers. In: Proceedings of the 17th Southern Forest Tree Improvement Conference, 6–9 June 1983; Athens, GA, USA; pp. 69–77.
• Squillace AE, Long EM (1981). Proportion of pollen from nonorchard sources. In: Franklin EC, editor. Pollen Management Handbook. Washington, DC, USA: USDA, pp. 15–19.
• Stoehr M, Mehl H, Nicholson G, Pieper G, Newton C (2006). Evaluating supplemental mass pollination efficacy in a lodgepole pine orchard in British Columbia using chloroplast DNA markers. New For 31: 83–90.
• Torimaru T, Wang XR, Fries A, Andersson B, Lindgren D (2009). Evaluation of pollen contamination in an advanced Scots pine seed orchard. Silvae Genet 58: 262–269.
• Tozkar CO, Önde S, Kaya Z (2009). The phylogenetic relationship between populations of marginally and sympatrically located Pinus halepensis Mill. and Pinus brutia Ten. in Turkey, based on the ITS-2 region. Turk J Agric For 33: 363–373.
• Van Buijtenen JP (1971). Seed orchard design, theory and practice. Southern Conf Forest Tree Imp Proc 11: 192–206.
• Vendramin GG, Lelli L, Rossi P, Morgante M (1996). A set of primers for the amplification of chloroplast microsatellites in Pinaceae. Mol Ecol 5: 595–598.
• Yazdani R, Lindgren D (1991). Variation of pollen contamination in a Scots pine seed orchard. Silvae Genet 40: 243–245.
• Zobel BJ, Talbert J (2003). Applied Forest Tree Improvement. Caldwell, NJ, USA: The Blackburn Press.