Cytogenetics of interploid hybridization of sturgeons

Arefjev VA.

In this study we investigated the chromosome pictures in four combinations of interploid hybrids: 1) Russian sturgeon (female) x sterlet; 2) sterlet (female) x Russian sturgeon; 3) Russian sturgeon (female) x great sturgeon; 4) Russian sturgeon (female) x bester (hybrid between great sturgeon and sterlet) in 3rd generation. On the basis of morphological assessments of somatic karyotypes, the following conclusions are drawn: a) all hybrid combinations have an intermediate karyotype with statistically significant bias of chromosome number (2n) to the diploid parent (2n=160-168, on average); b) the variation in all karyotype parameters is relatively high with a coefficient of variation (CV) of more than 12% (in comparison with 2-4% in “pure” species); c) taking into account the known relationship between increased karyotype variability and decreased fertility, or, more precisely, survivorship of progenies (as had been shown on successive generation of the bester), a high level of chromosome set variation in interploid hybrids is proof of practically complete sterility.