Аннотация:The breeding goal of the Genetic and Breeding Department, University of South Bohemia, Research Institute of Fish Culture and Hydrobiology at Vodňany along with the testing stations was to test weight, survival and heterosis effect in low, medium and high altitudes (250, 400 and 750 m respectively) above sea level. The breeding programme is focused to search for heterosis effect of hybrids by means of top-crossing. A newly established Hungarian synthetic mirror carp strain (HSM) was chosen for testing as a maternal strain. The HSM, as well as wild Amur carp (AC), Ropsha carp (ROP) and Tata carp (TAT) were used as paternal strains. The genetic distance between the maternal strain and the paternal ones according to Roger's test was 0.19 for AC, 0.15 for ROP and 0.12 for TAT. The first season of the top-crossing test on up to 4-month-old carp was performed by means of separate rearing of each group of fry with controls. The cross-bred HSM × ROP gained the best survival of 65.80 ± 38.45% compared with 53.40 ± 30.63%, 49.00 ± 45.95% and 34.90 ± 23.22% for HSM × AC, HSM × TAT cross-breds and purebred HSM respectively. The highest significant corrected weight was obtained with HSM × ROP cross-bred (43.95 ± 1.33 g), compared with HSM × AC cross-bred (38.96 ± 0.93 g), and significantly low corrected weights were obtained with HSM × TAT cross-bred and HSM purebred (28.08 ± 1.31 and 27.82 ± 0.97 respectively. Significantly, the highest heterosis effect was obtained in both HSM × AC, 62%, and HSM × ROP cross-breds, 58%, compared with HSM × TAT crossbred, 18%), as predicted from the highest genetic distances. Also, a HSM × ROP cross-bred was very adaptive to three different altitudes, regions and management in pond stations and meteorological conditions, in accordance with the best results in total altitude conditions.
