Morphometric and heterotic analysis on two breeds of Apis mellifera and their filial generation

ObjectiveMorphological characteristics and heterosis of two varieties of Apis mellifera and their cis-hy-bridization and trans-hybridization offspring were compared in order to provide references for further research on productivity and heterosis of the two varieties.MethodTwelve samples of American-Italian hybrid bees, the honeybees of high yield royal jelly breed and their filial generation (cis-hybridization, trans-hybridization) were collected. Forty morphological indexes of fifteen bees per group were measured to calculate heterosis rate for factor analysis, discriminant analysis and cluster analysis.ResultIn 20 body size-related morphological indicators, 15 indicators of the honeybees of high yield royal jelly breed were higher than those of American-Italian bees. Seventeen body-related indicators of the trans-hybridization progeny were higher than those of cis-hybridization offspring. Among the 8 body color related morphological indicators, average color value of the honeybees of high yield royal jelly breed was higher than that of American-Italian bees. Average color value of the trans-hy-bridization progeny was lower than that of cis-hybridization. Among the 9 optimized productivity related indicators, heterosis of the trans-hybrid offspring was better than that of cis-hybridization offspring. Factor analysis results of the four types of Italian bee species showed that total variation coefficient of the three factors was 53.291%, mainly with the characteristic indexes of size. Discriminant analysis results showed that the cis-hybridization offspring, the trans-hybridization progeny and the honey-bees of high yield royal jelly breed were basically in the same group, while the American-Italian bees were relatively separat-ed. Clustering analysis results showed that the trans-hybridization progeny, the honeybees of high yield royal jelly breed and the American-Italian bees gathered for a branch, while the cis-hybridization offspring was separate. ConclusionEven if the parents are the same, morphological indexes of the offspring are totally different under different hybrid equipping methods.