The document summarizes a study on the genetic structure of an Austrian relict population of English yew (Taxus baccata L.). A total of 2236 individual yews were observed with an average diameter at breast height of 8.8 cm. Isozyme analysis of 10 gene loci found 36 alleles and high genetic diversity, with an average of 3.4 alleles per locus and 90% polymorphic loci. Genetic parameters like expected and observed heterozygosity were estimated for the overall population and across different treatments, sexes, and other studies, showing generally high genetic variation in the population.

1. On the structures and genetics of an Austrian relict population of English yew ( Taxus baccata L.) AMALESH DHAR*, Raphael Klumpp, Herwig Ruprecht, Harald Vacik Institute of Silviculture, Department of Forest and Soil Sciences, University of Natural Resources and Applied Life Sciences, Peter-Jordan Str. 82, A-1190 Vienna, Austria. *Corresponding author (amalesh.dhar@boku.ac.at) Results and Discussion We observed in total 2236 no of individual yew with DBH ≥ 5 cm where the average DBH, height and basal area were 8.8 cm, 6.3 m and 3.20 m 2 ha -1 respectively (Table -2). The average extracted timber volume was 416 Vfm ha -1 whereas highest the volume was extracted from the treatment no II although 27 % of the total stand volume was removed. For evaluating the genetic structure of the yew population 10 isozyme gene loci and 36 alleles were studied where the mean number of alleles per locus was 3.4 and 90 % of the gene loci were polymorphic. Among these 10 loci only one locus SKDH-A is monomorphic. T he average expected heterozygosity was estimated to be ( He ) 0. 292 and the mean observed heterozygosity ( Ho ) 0.2 55 respectively (Table 5 ). To obtain clear information about the genetic structure, data were analysed as male, female and unidentified as well as different silvicultural treatments (see table 3 and 4). Having a closer look to table 3, the range of alleles per locus was 2.7 to 3.0 in respect of the different treatments operation however the total no of alleles per locus for the whole population was 3.4. Comparing the heterozygosity there was no big difference among the different treatment. From the bud analysis it was shown that the mean no of alleles per locus was 3.0 whereas in male, female and unidentified it was 2.9, 2.5 and 2.7 respectively. Regarding the observed heterozygosity there is no difference between male and female which is some how justified by Hertel (1996) interpretation though the unidentified sample shown high hetrozygosity 0.315. The over all estimation of all genetic parameters of the population compared to other studies revealed in Table 5 where we have found more alleles per locus and less observed heterozygosity 0.255 with respect to other studies. It is also mentionable that in our study t hree seeds from each tree h as been used to get the preliminary genetic structure of yew population , although 6 seeds from each tree is recommended. Rest of the three seed will be analyse to predict the actual genetic structure of whole population . From the overall observation it is concluded that the Stiwoll population has high genetic diversity in respect of number of alleles per locus and high percent of polymorphic loci. Considering the in-situ consevation effort, the gene conservation forest S tiwoll represents high endurance ability and a valuable gene pool for future conservation of Taxus baccata in Austria. References Cao Von C.-P., Leinemann M. Z., Finkeldy R. 2003. Study of the genetic variation and differentiation of yew ( Taxus baccata L.)Stands using Isozyme and DNA Marker. Allg.Forst-u.J.Ztg.,1/2:21-28 Cheliak W.M., Pitel J.A., 1984.Techniques for starch gel electrophoresis of enzymes from forest tree species. Inf. Rep. PI-X-2, Petawawa Nat. For. Inst., Canadian For. Service., Agric. Canada. Dhar, A., Ruprecht, H., Klumpp, R., Vacik, H., 2006. Stand structure and natural regeneration of English yew ( Taxus baccata L.) at Stiwollgraben in Austria, Dendrobiolog, 56,19-26. Dhar, A., Ruprecht, H., Klumpp, R., Vacik, H., 2007. Comparison of ecological condition and conservation status of English yew population in two Austrian gene conservation forests. Journal of Forestry Research, 18 (3), 181-186 Hertel H., 1996. Vererbung von Isoenzymmarkern bei Eibe ( Taxus baccata L). Silvae Genetica 45:284-290. Herz H., Bernhard A., Nebenführ W., Slunsky R., Litschauer R., Heinze B. ,2005. Das Eibenvorkommen in den Österreichischen Generhaltungswäldern. Poster bei der “12. Tagung der Eibenfreunde”, 2005 Sept 29 –Oct 2; Kempten in Allgäu. Lewandowski A., Burczyk J., Mejnartowicz L., 1995. Genetic structure of English yew ( Taxus baccata L .) in the Wierzchlas Reserve:implications for genetic conservation. Forest Ecology and Management 1995 ;73:221-227. Svenning, J.-Ch., Magárd E., 1999. Population Ecology and conservation status of the last natural population of English yew Taxus baccata in Denmark. Biological Conservation, 88, 173-182. Thomas, P.A,. Polwart, A., 2003. Taxus baccata L. Biological flora of the British Isles 229. Journal of Ecology, 91, 489-524. Tröber U., Paul M., Kahlert K., 2004. Genetic characterisation of English yew ( Taxus baccata L.) in Thuringia and Saxony as basis for gene conservation. 11. Arbeitstangung von 20-22. September 2004 in Teisendorf, pp 275-288. Table 1 . Enzyme system used for electrophoretic analysis of the yew population Figure 1. Location of the study population( ) Table 2. Different chracteristics of forest parameters according to treatments Table 5. Estimation of genetic variation for parameters in different studies on Taxus species Table 3. Metric traits of the trees sample and estimation of different genetic parameters according to treatments Table 4. Estimation of different genetic parameters according to sex on the basis of buds samples Introduction English yew ( Taxus baccata L.) is a slow growing, shade tolerant, long-liv ing dioecious conifer tree of temperate forests. It grows as a subordinate but sometimes habitat-determining species in a range of different forest types (Thomas and Polwart 2003). In Austria , yew is predominantly found in Beech and Norway spruce-dominating montane forest s . In recent time the distribution of yew species has been severely reduced due to natural disturbance and human intervention s . The reasons for the yew decline have been discussed by many articles (see Svenning and Magard 1999, Bugala, 1978, Dhar et al., 2006; 2007 ). Some of them suspected that a low level of genetic variation might be one of the main reasons f or a yew decline . H owever Lewandowski et al. (1995) observed high level of genetic variation at the Wierzchlas reserve in Poland although it is a declining population . The estimation of genetic variation for allozymes of plants within and among populations components can provide the basis for the conservation of genetic diversity of plant programmes (Hamrick et al.1991). These estimates of allozyme diversity, along with information on population biology and ecology of plants, can also be used as yardstick to measure the effectiveness of in-situ and ex-situ conservation programmes of tree species. The “Stiwoll” valley was identified as an gene conservation forest in 2004 ( Herz et al.2005 ) for in-situ conservation of yew. Objectives The main goal of this study is to characterize the structure and genetic of the all yew individuals. The isozyme biochemical marker s were used for understanding of the genetic structure of the yew population. Materials and Method The “Stiwoll” valley is situated in the Eastern Alpine mountains (Fig.1) with estimated 4.6 ha of land at 580 to 700 m a.s.l. elevation . Altogether, t h ree different levels of thinning operation were carried out to find the best way of silvicultural treatment for attaining the management approach : I) an intensive thinning (T I) by reducing 56 % of the standing volume, II) moderate thinning (T II) with a removal of 27 % of the standing volume and III) third no thinning (T III). The y ew stand structure was illustrated with respect t o height distribution, DBH distribution, basal area , tree voluame etc. A total bud sample from 109 trees and a seed sample from 39 trees were taken for isozyme analysis. Horizontal starch gel electrophoresis was applied for separating the isozymes and S even enzyme systems (Table 1) were chosen for this study, which are known to exhibit polymorphism in at least one of the encoding gene loci (Hertel 1996) . Electrophoretic procedures and staining protocols followed the methods described by Cheliak & Pitel ( 1984 ) and Hertel ( 1996 ) . We used the GSED-1.1 (Gillet 1998) computer programme to analyse the genetic data. Genetic diversity was assessed by following parameters: percentages of polymorphic loci (P), average number of alleles per locus (A/L), average expected (He) and observed (Ho) heterozygosities per locus and gene pool d i versity (Ne) among the populations . Acknowledgement We would like to thank Ing. Schuster from local forest authority, Ing. Monika Lex for technical support during lab work and the Forest Province Office of Styria for financial support. We also thank the Österreichische Orient-Gesellschaft (ÖOG) for the One-World Scholarship and funds for participating to this conference. 3.4.11.1 4 5 LAP-A LAP-B Leucine-aminopeptidase 5.3.1.9 5 PGI -B Phosphogluco isomerase 2.7.5.1 4 PGM - A Phosphoglucomutase 1.1.1.25 3 SKDH-A Shikimate-dehydrogenase 1.1.1.44 2 6-PGDH- A 6-Phosphogluconate-dehydrogenase 1.1.1.42 3 4 IDH-A IDH-B Isocitrate-dehydrogenase 2.6.1.1 2 3 AAT- A AAT- B Aspartate-aminotransferase E. C. number Allele no Gene locus Enzyme 50-80 9-58 30 148 Sample size Taxus baccata Species 5 6 18 10 No of gene loci Tröber et al. (2004) 7.839 0.308 0.302 1.4 -- -- Cao et at. (2003) -- 0.316 0.340 1.48 2.62 (80.6) Lewandowski et al. (1995) -- 0.419 (poly. loci) 0.429 (poly. loci) 1.37 2.83 61.11 This study 51.68 0.292 0.255 1.41 3.4 90 He Ho Ne A/L P 95 (%) Different studies Hypo. gametic diversity Parameters 148 38 32 78 No of Sample 51.68 0 .292 0.255 1.41 3.4 90 6.5 9.6 total 30.37 0.260 0.221 1.35 2.8 80 6.7 10.1 T III 53.25 0.303 0.272 1.42 2.7 80 6.6 9.4 T II 60.09 0.302 0.265 1.43 3.0 90 6.2 9.3 T I Hypoth. game Diversity He Ho Ne A/L polimorphe Loci P 95 (%) Parameter Ave. Height [m] Ave. DBH [cm] Treatment 418 321 530 403 Volume extraction [Vfm ha -1 ] 33 0 33 57 Proportion of reduction [%] 6.3 6.6 6.5 5.9 Ave. Height [m] 8.8 27.5 4 959 2236 4.55 Over all 8.9 30.99 882 779 1.76 T III 8.6 34.13 1398 764 1.16 T II 8.8 17.77 648 693 1.63 T I Ave. DBH [cm] Basal Area [m 2 ha -1 ] Other trees no. [nha -1 ] Total no.yew Trees ≥ 5 cm DBH Area Treatment 69.59 0.312 0.286 1.45 3.0 90 109 Total 112.25 0.349 0.315 1.52 2.7 90 27 unidentified 55.09 0.298 0.284 1.42 2.5 90 38 Female 58.79 0.301 0.270 1.42 2.9 80 44 Male Hypoth. game Diversity He Ho Ne A/L Polimorphe.loci P 95(%) Parameter Sample size Sample