Assessment of Exterior Indicators of Parental and Hybrid Forms of African Catfish Clarias gariepinus

This article presents a comparative study of morphometric exterior parameters of African catfish Clarias gariepinus of parental forms (Mikhailovskaya and Taman breeds) with their hybrid offspring of the first two generations and one second generation. Nonparametric analysis (U Mann–Whitney criterion) revealed significant differences between the average values of the five samples for 12 of 17 morphometric measurements. It was found that hybrid individuals of the first and second generations have a different exterior phenotype from the parental one and are characterized by an elongated body, an elongated tail and a large head size. In the course of the subsequent principal components analysis two large clusters were revealed, the first of which was formed by individuals of the parental groups (Mikhailovskaya, Tamanskaya), and the second was formed by hybrid generations. In this case, the hybrid individuals formed a rather heterogeneous group, in which the F₁ hybrids of the first and second generations were similar and sufficiently consolidated. The individuals of the first generation, selected by the “growth rate” trait, demonstrated significant variability. The results show that the variability of the exterior indicators of the cultivated lines of C. gariepinus of the Mikhailovskaya and Tamanskaya breeds did not undergo significant changes during their isolated cultivation in conditions of a closed water supply cycle, and the hybrids obtained from their crossing, taking into account the higher average weight, are characterized by improved morphometric indicators and can be used to increase the yield of commercial products or in further selection programs for developing new breeds.