Genetic diversity of Russian sturgeon broodstocks in the Azov Sea basin and evaluation of the application of optimal crossbreeding schemes to increase the adaptive potential of released juveniles

   The aim of this study is to assess the level of genetic heterogeneity in broodstock populations of Russian sturgeon in the Azov–Black Sea basin, as well as to analyze different parental pairing schemes aimed at preserving and enhancing the genetic diversity of offspring.

   Methods: microsatellite DNA polymorphism was analyzed based on fi ve loci (AoxD161, AfuG41, An20, AfuG51, AoxD165) in three Russian sturgeon broodstocks – the Don Sturgeon Hatchery (DOZ), the Temryuk Sturgeon Hatchery (TORZ), and the Grivensky Sturgeon Hatchery (GORZ), with 100 specimens analyzed from each broodstock population.

   Novelty: or the first time, a comparative assessment of the genetic heterogeneity of broodstock populations from three main sturgeon hatcheries of the Azov Sea basin was conducted, followed by an evaluation of the genetic heterogeneity of the predicted offspring based on parental genotypes.

   Results: High levels of genetic variability were observed in all studied samples (Mean Ho = 0.920-0.940; Total Na = 59-60; Mean Na/locus = 11.8-12); however, pronounced intergroup differentiation in allele structure was detected. The broodstocks DOZ and TORZ exhibited a more stable genetic state, whereas GORZ showed a tendency toward increased homozygosity at specifi c loci (AfuG51 and AoxD165). Simulation of mating pairs demonstrated that the use of optimally selected parental combinations increases the expected offspring heterozygosity to 0.991-0.995 and reduces the proportion of weak heterozygotes by anaverage of 46 % compared to random pairings.

   Practical significance: The results of this study can be applied for the scientifi cally based selection of parental pairs in broodstocks of Russian sturgeon, aiming to preserve allelic diversity and maintain a high level of offspring heterozygosity in artificial breeding programs.

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