Báo cáo khoa học: "Intra- and interpopulational genetic variation in juvenile populations of Quercus robur L and Quercus petraea Lieb"

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Original and genetic juvenile of Quercus robur L and Quercus petraea Liebl G S Herzog HH Institut für und der für Wald, Schnee und 111, 8903 — In each of 5 of Quercus robur and Q petraea (single and samples), genetic variation was with respect to 13 enzyme loci. Genetic control and of was verified by means of of full-sib families. The observed average were 21.3% Q robur and 21.9% for Q petraea of 56.6 and 56.7 The mean number of locus is 3.2 for Q robur and 3.1 for Q petraea. The small genetic indicate mi- nor The genetic distances between pairs of samples indicate between Most of the single samples could be proven to share a of the entire gene pool than each of the samples. There is a strong genet- ic between Q robur and Q petraea in terms of common alleles. It is concluded that, more than in other species, large genetic variation must be into oak in order the ability of these species to adapt to robur / Q petraea / / / diversity / genetic distahce / gene- tic — génétique intra- et dans de jeunes de Quer- cus robur L et de Quercus petraea Liebl. La générique a été estimée dans 5 de Quercus robur et 5 de Q petraea à partir de 13 loci des isozymes a été au préalable vérifiée par Send all to address 2. de dans les Les valeurs moyennes de de 21,3% chez Q robur et 21,9% chez Q petraea. Les mêmes valeurs pour les sont de 56,6% et 56,7%. Le nombre moyen d’allèles est de 3,2 pour Q robur et 3,1 pour Q petraea. Les sont peu élevées. Les distances indiquent de très fortes entre elles. Les prises partagent une partie plus faible de du pool génétique que les entre elles. Les allèles communs indiquent une très forte entre Q robur et Q il est de conserver une génétique élevée dans les manière à maintenir leur aptitude à s’adapter à des milieux robur / Quercus petraea / allozymes / / diversité / distance génétique robur L oak) petraea Liebl (sessile oak) be- long to the major deciduous tree Germany. Like Fagus sylvatica L, oaks are carrier tree species of complex which range from the to the or even regions. Oaks are species with forest rotation cy- cles of 200 or more years. Oaks are to more over time than any tree species. In the study variation and its on the ability of tree to survive oaks may function well as model objective of the present study was to proceed in the of the in oak and thus in of the natural of forest Data on patterns of ge- netic variation will to a better of of of oaks and are needed as the choice of material, treatment as well as for and of genetic AND each species, 5 were utilized seed lots (see table I) which are commonly used for in Germany. Two of material are involved: 1) seed lots which originate from harvest in stands which all together belong to the same region of and 2) material which oak stands which cover areas of All stands are supposed to be A total of 1605 at the age of 2 yr. For location of of the studied samples, see Ziehe control and of verified by utilizing full-sib and their parents of Q robur and Q and Hattemer, 1990). For of bud and leaf tissues, enzymes were by and focusing mean of see and Ziehe (1991). Enzyme systems dependent of such as acid or were excluded from further studies. Ten systems were studied and EC No / in, (GOT , (= aspartate AAT)), malate (PER, isomerase (PGM, (SKDH, were scored at 13 AP-A, DIA-A, GOT-B,C, IDH-A, 6PGD-A,B, PGI-B, PGM-A, of genetic variation was measured by means of the observed and the (Ha,Hc), et al, number of alleles and of genotypes per lo- cus, and the genic (allelic) 1987). variation was by genetic distance 1974) and 1986); for a summary see Gregorius AND Quercus robur and Q degrees of are in tables II and III; The (Hc) are given in addition to the observed (Ha) because the latter values can be biased as a of their upon the gene For Ha, the given mean for Hc it is equal to the ratio of Ha values to the summed maxi- mum Ha values showed among the gene loci. Loci were: AP-A, PER-B and PGM-A. the samples was by the gene loci PER-B and SKDH- A. The mean Ha value for the 2 oak spe- cies were nearly the same: 21.3% for Q ro- bur and 21.9% for Q petraea. The of the slightly smaller than the (21.1 % for Q robur) or identical to trends in the Hc values III) as compared to the Ha a of in the gene among samples and among loci within samples. For PER-A and PGM-A reflected great Ha values but small Hc values. This leads the Ha values to appear large but to be small in reality, if the potential to form is taken into The opposite trend was revealed, by the loci GOT-B and 6PGDH- B: large Hc values that small Ha values could not have been much larger due the (1 frequent and a few very rare alleles). Loci AP-A, DIA-A, IDH- A, PER-B and PGM-A have 2 or 3 variation with respect to MDH-B and MDH-C was primarily a of gene close to in most of the samples. The values showed little deviation among the samples. The overall mean values of the species were nearly identical 56.7%, were lacking and the samples vs ones) did not seem to affect The did not from those reported for other tree species, such as Fagus values (2-yr old plants from 5 samples genotyped at 12 gene loci) were; Ha = 22.2% and Hc = 52.4% and Ziehe, in terms of of alleles or genotypes per locus in table IV. There is no occurs in all samples of one not in any sample of the other which are in some of the samples of only one species are so 1 %) that sample size may account for in the other largest mean numbers of revealed by the gene loci and AP-A (4.7), the smallest ones by MDH-B (1.5) and MDH-C (1.8). The means of the samples from compared to single (3.4 vs 2.9 for Q robur, 3.3 vs 2.8 for Q petraea. The overall means of both spe- cies are nearly (3.2 and 3.1 al- leles mean number of genotypes per lo- cus varied more among the samples than the gene number did. This finding is not only a of the sample sizes of samples 5,7 and 10 are small (between 72 and 96 (see table I) but these not reveal the smallest number per locus. In contrast to the mean number of alleles per locus, the values for genotypes in Q robur than in Q petraea, ie, 5.1 vs 5.4 genotypes per locus (for Q ro- bur, this is to 76% of the maxi- mum mean number of for Q petraea to 85%). For the it is suggested that of the system of the may to these (allelic) values (see table V) as harmonic means. The gametic diversity equal to the number of gametic types which can be produced by of each sample on the basis of their 13-locus vl is the diversity at locus l) et al, 1986). This measure potential for creating genetic the next and is therefore of the of forest tree most cases, the single locus genic reflected trends similar to in the genic values for PER-B and AP-A). This was not true in cases of deviating of allele for locus DIA-A reflected on the numbers of alleles but larger than the GOT-C locus vs 2.1; GOT-C: 4.0 vs 1.5). The this is the greater the allele from the state in the case of GOT-C that of variation among the of the samples was smaller than that among the mean number of alleles per locus (see table IV). In both species, there was not more deviation between the val- ues from samples and those from single gametic revealed a large variation among the samples. The sample size did not seem to affect these values 2 of the smallest samples (5, 7) show quite large values. In the case of Quercus robur, the values of samples did not from those of the mixed samples (on the average 136.9 vs 137.4), but are smaller in the case of (164.9 vs Quercus robur and Q table VI, results are given for 2 out of 13 loci: AP-A those loci which re- veal in both species, at least for some pairs of samples, large genic SKDH-A, showed on the large values for Quercus petraea small values for Q robur. In SKDH-A reveals greater the 2 species than any other the results of a samples (log ratio test in tables), it can be stated that genic distance values 0.1 will reveal in most cases (at least at a level of 0.05). Genic distances larger than 0.2 can be expected to indicate genetic For of samples, these values are eg, in case of 8 and 9 (AP- A). Each of these can be easily from the other not from each other. The be- tween 8 and 9 is a because these 2 samples from single and should re- lect more specific genetic samples. As can be seen from the same table, this trend was not confirmed The highly specific ef- fect of adaptive loci may account for was by means of the genetic distances sample an the remaining ones combined in order to form the In this way genetic variation was measured as a whole and not only in 1 and 2 genetic for 5 out of 13 gene loci (for a summary of numerical and Ziehe, 1991). For each species, the graphs refer to the In each graph, the radius of the dotted line is equal to the average lev- el of at that given scale measures the of genes by which any from the For the radii of the sec- tors are equal to the of genes by which one sample differs from remainder (the angles of the sec- tors to the sample size). The more the sector radii approach the more of the the genetic of this is to reduction of In the combined (see graph ’gene pool’), effects can be single locus graph show that level of varied among the loci and among For both species, a large level was found for instance, between the 2 evident in the case of SKDH-A and to a certain extent also those of AP-A and GOT-C. The gene pool greater among of Quercus petraea than of Q robur. Within the first 4 and 5 were although the among the samples were small. In the case petraea, all samples except no 6 were above average. which from seed in single (no 4 and 5, and 8, 9 and 10) tended to be more than the remaining samples which de- scend from mixtures. This means that single share a smaller of genetic than the gene marker reveals a between Quercus robur and Q petraea. None of the genes in only one of Within each species, appear to be smaller than in sever- al other tree species (for of and see 1991). Because in adult stands is still it cannot be excluded that might Quercus but not life stages. The genetic was very large in all samples including finding concurs with results of a re- cent study in 32 European petraea (Kremer et al, 1991). Great variation could a strategy of survival of species which are and exposed to genetic indicate ie, a with and a few rare alleles. distances between pairs of sam- ples indicate in many cases. These values tend to be high- er than those of Kremer et al (1991). genetic samples tend to share a larger of the entire gene pool than each of the Gene loci reveal very different each of the adaptive gene loci may be subject to different selective thus monitor genetic or among in a way. The results presented herein forest tree breeding and robur and Q petraea need to take into account large genetic genetic seems to to the to which oak are exposed. in it appears that large genetic should be in in order to maintain the of these to adapt to and in complex technical of G Dinkel is This study was by the of the European GD XII, Brussels, (1972) Erste des Gesetzes über Pflanzgut (1 FSaat V). I, 92, HR (1974) Abstand 1. Zur Silvae Gen- et 23, HR (1978) The concept of genetic and its formal to and genetic distance. Math Biosci HR, Roberds JH (1986) of genetical among Theor Appl Genet 71, HR, J, G (1986) Spatial and temporal genetic among the seed in a stand of L. Heredity 57, A, Petit R, Zanetto A, Fougere V, A, Wagner D, Chauvin C (1991) and organelle gene diversity in Quer- cus robur and Quercus petraea. In: in European of G, Ziehe M, G (1991) Survey of genetic inferred from enzyme gene markers. Variation of Forest Tree Europe G, Ziehe M, G, Gregorius HR (1986) genetic variation in forest tree In: Proc 19th IUFRO World 1986, div 2, vol II, G, Hattemer HH (1990) Breeding of Oaks. Final Report, MA 1 CEC, DG XII, Brussels, G, Ziehe M (1991) Genetic in of Fagus Quer- cus petraea, and Q robur in Germany. In: Ge- netic Variation of Forest Tree in Europe G, Ziehe M,