Genetic diversity, structure and differentiation of Gmelin larch (Larix gmelinii (Rupr.) Rupr.) populations from Central Evenkia and Eastern Zabaikalje [Russian Fedetation]

On the basis of 17 loci, coding allozyme diversity G-6-PD, 6-PGD, IDH, MDH, SKDH, GDH, GOT, LAP, EST, ME, the values of the main parameters of genetic variability, structure and differentiation of Gmelin larch (Larix gmelinii (Rupr.) Rupr.) populations from Central Evenkia and Eastern Zabaikalje were established. The studies were conducted by method of horizontal starch-gel electrophoresis. 76.5% of gene loci assayed were revealed to be polymorphic at 95% and 94.1% at 99 % criteria. The mean number of alleles per locus, the mean observed heterozygosity as well as the mean expected heterozygosity and the effective number of alleles were equal to 2.59, 0.100, 0.141 and 1.21, respectively. A11 populations of L. gmelinii examined showed a deficit of heterozygous genotypes. The highest deficit of heterozygotes was characteristic of L. gmelinii populations from Evenkia (Fsub(is)=0.2672). More than 92% of total genetic variability was within the population and only 7.89% (Fsub(st)=0.0789) was among the populations. The mean genetic distance D (Nei 1972) between populations ranged from 0.0025 to 0.0343 and averaged 0.0168. The most substantial differences were revealed between populations from Evenkia and Eastern Zabaikalje (D changed from 0.0270 to 0.0343). The populations of L. gmelinii in Evenkia were slightly differentiated (D changed from 0.0025 to 0.0042). The data obtained suggest that geographically distant from each other populations of L. gmelinii from Central Evenkia and Eastern Zabaikalje have more significant level of genetic differentiation in comparison with geographically close populations from Evenkia. The mean value of genetic distance D between populations from these regions is equal to 0.03. Analysis of data obtained as part of the study of genetic variability and differentiation a great variety of conifer species showed that such extent of genetic differences is usually observed between populations belonging to different geographical races of a single species (Millar et al. 1988, Conkle et al. 1988, Krutovskii et al. 1989, Hamrick and Godt 1989 and etc.). On this basis the larch population from Evenkia and Eastern Zabaikalje can be regarded as geographic races of L gmelinii. Results of our studies confirm the opinion of Abaimov and Milyutin (1995) about heterogeneity of L. gmeliniii in various regions of its range.