配套系在动物育种中能最大程度地利用品系的杂种优势, 以获得最大的经济效益, 配套系的选育是今后肉兔遗传改良的发展趋势。肉兔父系以选择平均日增重和上市体重为主, 断奶后生长性状一般与料肉比呈有利的负遗传相关, 可作为料肉比的间接选择标准。而母系以选择断奶数和产仔数为主。大多数繁殖性状的遗传力较低, 在进行遗传评估时应当尽可能全面地收集个体和相关亲缘关系个体的记录。重复观测值动物模型下的BLUP估计是进行肉兔专门化品系选育的主要方法。虽然窝内个体数性状的直接选择效率低于生长性状, 但其杂种优势一般高于生长性状。通过计算杂交参数和比较同代杂种与纯种间的生产性能可以进行杂种优势的估计。文章对肉兔专门化品系的选育、杂种优势的利用和良种繁育体系的建立进行了综述, 总结了肉兔专门化品系的培育方法, 性状选择的标准以及杂种优势的估计结果。
Best-hybridized crossing should ideally result in optimal exploitation of heterosis of lines and capitalize on expressed heterosis. Rabbit breeding is heading in the direction of breeding for best-hybridized crossing of meat rabbits. Most special sire lines are selected for post-weaning average daily gain and marketing weight. Post-weaning growth has a negative and favorable genetic correlation with the feed conversion ratio, which is used in indirect selection for feed conversion ratio. The most common selection criteria for special maternal lines are related to litter size at birth or at weaning. Since the heritability of most reproductive traits is low, we must collect as many individual and relative records as possible in the genetic evaluation of rabbits. The BLUP procedure under an animal repeatability model is the most common procedure used for evaluation of animals in selection programs for special lines of meat rabbits. Direct selection for litter size is less efficient than selection for post-weaning growth, but the estimation of heterosis is generally higher for litter size than that for the post-weaning growth. Evaluation of heterosis could be performed by estimating crossbreeding parameters in the cross or comparing contemporary productivity among purebreds and crossbreds. Here, we reviewed breeding of special lines, exploitation of heterosis of crossbreds, and establishment of crossbreeding system of hybrid meat rabbits and summa-rized the methodologies of breeding special lines, criteria in selection programs, and the result of heterosis estimates.
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