Effect of inbreeding on some characters of bees

In a set of colonies headed by free-mated and also instrumentally inseminated honey bee queens (Apis mellifera) the effects of inbreeding of worker bees, queens and fathers (queens of drones used for the insemination) on four important characters were evaluated. Bee colonies were of carniolan race (Apis mellifera carnica), of two queen breeders in the north of Slovakia. Characters included in the analysis were: honey production in the spring nectar honey flow, honey production in the summer honeydew honey flow, the hygienic test as a parameter of the behavioral bee resistance to infectious brood diseases and proportion of parasitic mites Varroa jacobsoni damaged by bees, from all mites collected from the hive bottom board at the end of summer. The influence of breeding on honey production in the summer honeydew honey flow was not significant. But in the spring nectar honey flow a positive and significant effect of inbreeding of queens was found. With every 1 % of the inbreeding coefficient of queens the honey production increased by 0.1032 kg. It is possible to explain the positive effect of the inbreeding of queens to honey production in the spring honey flow to its biological role during the spring colony growth. For the hygienic test, only the regression on inbreeding of queens was significant. The regression of the ability of bees to damage mites Varroa jacobsoni on inbreeding coeficient of bees was positive and significant. With every 1 % of the inbreeding coefficient of bees the percentage of bee-damaged mites increased by 0.317 %. The result signals the possibility of improving the character using the close inbred breeding. The fact that higher values of inbreeding did not make significantly worse the analyzed characters may be connected with the intensive selection of these characters in the apiaries. This way, the expected expression of the inbreeding depression may be compensated for by the selection gain in the analyzed characters. The significant regressions of two from four characters to the inbreeding coefficient of queens suggest the existence of a strong maternal effect