Genetic Evaluation by Microsatellite Loci of Pinus sylvestris L. Plus Trees

Abstract

In this study, a comparative analysis was performed to estimate the genetic diversity levels of Pinus sylvestris L. in 49 seed orchards of I generation and progeny test plantings using 4-nucleus microsatellite loci. The seed orchards are located in the Petrozavodsk and Zaonezhye regions of the Republic of Karelia. The progeny trials were created by half-sibling seed progenies of the clones in the Petrozavodsk seed orchard. Micro-Checker software was used to identify null alleles and exclude genotyping errors. Coefficients of genetic originality were determined by examining the genetic structure of breeding objects in relation to the proportion between the rare and the dominant alleles for each selected tree. A major part of the rarest alleles (27.3–37.0 %) and a small fraction of the most common alleles (3.3–14.8 %) were detected for the distinct range of the pine trees in both seed orchards and test cultures. The largest number (40) of all identified alleles (51) was found in the Petrozavodsk seed orchard. The Hardy-Weinberg test comparing allele rates to expectational values showed a lack of heterozygotes in each category of the empirical substances. The selected material also had high levels of allelic and genetic diversity. The average number of alleles per locus ranged from 7.75 to 10.50. The average effective number was from 5.00 to 6.54. The observed heterozygosity varied from 0.60 to 0.70. The expected heterozygosity was 0.63–0.71. The numerical deviations were statistically insignificant. The AMOVA molecular dispersion result was 5 %, indicating the absence of significant genetic differentiation between the breeding objects. The heterozygote deficiency was caused not only by the presence of null alleles, but also by the selection. Namely, the set of alleles in the experimental material, randomly selected from a limited number of genotypes (clones), may differ from the natural population. The high level of the rarest alleles in the given range of the pine trees can also be explained as a selection effect. The results obtained in this study are important for creating breeding objects with higher genetic value. For citation: Ilinov A.A., Raevsky B.V. Genetic Evaluation by Microsatellite Loci of Pinus sylvestris L. Plus Trees. Lesnoy Zhurnal = Russian Forestry Journal, 2023, no. 3, pp. 48–68. (In Russ.). https://doi.org/10.37482/0536-1036-2023-3-48-68