运用聚丙烯酰胺凝胶等电聚焦技术（IEF-PAGE），对有代表性的王浆蜂蜜双高产的"浙农大1号"意蜂品种（浙意，Ea）和中国本地意蜂（本意，Eb）、美国意蜂（美意，Em）、澳大利亚意蜂（澳意Eo）、意大利意蜂（原意，Ee）等5个意大利蜂（Apis mellifera Ligustica）品种试飞前的幼龄工蜂进行了苹果酸脱氢酶（MDH）同工酶的基因型、基因型频率、基因频率、杂合度和纯合度的研究。由a、b、c 3个等位基因编码的MDH图谱第二区带应有的a/a、a/b、a/c、b/b、b/c和c/c 6种基因型，在Ea、Eb、Ee 3种意蜂中全部出现；在Eo中出现a/b，a/c，b/c，c/c 4种，在Em中出现a/c，b/c，c/c 3种。联列表独立性检验结果，5个意蜂品种间的基因型频率、基因频率、杂合度、纯合度存在显著差异。

The young workers (in three days) of five races of Apis mellifera ligustica- ZAU — 1 Italian honey bee (Ea), Chinese Italian honey bee (Eb), American Italian honey bee (Em), Italian Italian honey bee (Ee) and Australian Italian honey bee (Eo) have been used to study the genotype, genotype frequency, allele frequency, heterozygous and homzygous degrees of the malate dehydrogenase Ⅱ (MDH Ⅱ ) isozymes with polyacrylamide gel isoelectrofocusing (IEF-PAGE). There are six genotypes (a/a, a/b, a/c, b/b, b/c, c/ c) in MDH Ⅱ that is coded by three alleles： a，b and c. All of them are found in Ea, Eb and Ee; four (a/b, a/c, b/c, c/c) are found in Eo; three (a/c, b/c, c/c) in Em.The genotype frequencies are aa (0.022), ab (0.028), ac (0.296), bb (0.007), be (0.140), cc (0.508) in Ea; aa (0.003), ab (0.011), ac(0.117), bb (0.006), be (0.156), cc (0.706) in Eb; aa (0.033), ab (0.203), ac (0.224), bb(0.021), be (0.252), cc (0.267) in Ee; aa (0.000), ab (0.000), ac (0.313), bb (0.000), be(0.253), cc (0.433) in Em; aa (0.000), ab (0.006), ac (0.011), bb (0.000), be (0.172), cc (0.811)in Eo. The allele frequencies are a (0.184), b (0.091), c (0.726) in Ea; a (0.067), b (0.090), c (0.717) in Em; a (0.008), b (0.089), c (0.903) in Eo. The heterozygosities (H) of the MDH Ⅱ locus equal to 0.464 in Ea; 0.284 in Eb; 0.679 in Ee; 0.566 in Em; 0.189 in Eo.

The results of test-independence show that there are significant differences in the distributions of genotype frequency, gene frequency, heterozygous and homozygous degrees among five races of Apis mellifera.