Assessment of the effect of heterosis by productive parameters of young-of-the-year carps obtained from crossing Ukrainian and Polish breeds

Purpose. The aim of the work was to study the effectiveness of using structural units of Ukrainian carp breeds in combination with Polish carp lines to obtain new promising lines for industrial cultivation at different levels of aquaculture intensification. Methodology. The studies were conducted in pond conditions at the State Enterprise Research Farm “Lviv Research Station” and at the State Enterprise Research Farm “Nyvka”. Females of the Galician and few scaled Nyvka hatchery line of intrabreed carp types and framed and scaly males of the Polish line imported from the fish farm of the Olsztyn Voivodeship were selected for crossing. During the autumn harvest, weights and lengths of fish juveniles were determined, based on which the main body composition indices were calculated: body length to height ratio (l/H), girth (l/O), and the Fulton’s condition factor (CF) was determined. The heterosis effect for the main productive parameters was calculated by exceeding the corresponding parameter in the inbred group over that of the original maternal line. The data obtained as a result of the experiments was processed using a graphic method. The significance of differences between obtained values was tested using ANOCA in MS Excel. Findings. It was found that in the first year of cultivation, the offspring obtained from crossing carp of Ukrainian and Polish selection allow, on average, increasing the productivity of fish farming water bodies compared to pure lines by 48.1% using Galician females, and by 54.6% using Nyvky females. The maximum manifestation of heterosis phenomenon in terms of individual body weight was observed in interbred YOYs obtained from Nyvky females, the superiority of which over pure lines was: for framed – 246.8%, for scaly – 230.5%. This parameter in YOYs obtained from a similar cross with Galician females, compared to the pure line, was 132.0% for framed and 143.5% for scaly. At the same time, the crossbred YOYs were characterized by a survival rate above 40.0% and exceeded the standard rate by 2–7%. Originality. For the first time, crossbred carp offspring from crossing offspring of Ukrainian and Polish selection in conditions of industrial cultivation in pond farms in Ukraine were obtained and comprehensively studied, the results of which showed that the heterosis effect on fish productivity on breeding ponds was at the level of 148.1–154.6%. Practical Value. The results obtained demonstrate the effectiveness of using new foreign carp lines to improve the genetic structure of domestic carp farming. A comprehensive analysis of the productive and biological parameters of the offspring obtained from the crossing of Polish lines and structural units of Ukrainian carp breeds will allow developing strategies for obtaining and growing new highly productive lines and crosses. Keywords: carp, genesis, survival, weight, growth rate, fish productivity, heterosis.