香港巨牡蛎杂交育种材料体系构建研究及杂种优势预测

Crassostrea hongkongensis is one of the most important bivalve species cultured in South China Sea coastal area. Based on the good understanding of its genetic background, the proposed project will aim at the following crossbreeding studies on this species:1) choosing at least four different populations with significant genetic variation and features as potential breeding materials for further studies; 2) establishing pure breeding lines using full-sib family selection, divegent selection and homogeneous matching techniques for assembling as many favourable genes and lingages as possible. And after several generation, an good "gene pool"which include the most potential parents for the coming hybydization should be created quickly;3) evaluate the parents' breeding values and general and special combining ability for each combination,using diallel-cross technique, and pridict heterosis and explain its genetic mechanism;4) analyze genetic structure of each generation and compare the genetic variability among groups to assist to the selection of the best canditate parents, using molecular marker technique; we expect to screen suitable markers to identify the hybrid offspring, and define the relationships between gene heterozygosities and their corresponding economic characters,and to facilitate the crossbreeding.With the implementation of this project,it is expected to get a better understanding genetically of the heterosis mechanism on mollusca hybridization.

香港巨牡蛎是我国华南沿海最重要的养殖双壳贝之一。本课题拟在我国华南沿海各主要地理分布群体的遗传背景分析基础上，1）筛选出四个遗传结构清晰、性状特点明显且群体间遗传差异显著的地理群体。2）采用家系选育、歧化选择、同质交配等方式对四个基础地理群体进行纯繁培育，聚合有利基因及连锁、增加优质高产基因频率,快速构建可用于高效杂交模式的基础材料体系。3)对经纯繁培育出的杂交基础群体采用双列杂交，分析育种值及各组合特殊配合力大小，为杂种优势预测及解释提供直接的依据。4）同时，采用分子标记技术对各中间材料体系逐代分析遗传结构变化及群体间遗传结构差异，科学评估该杂交体系效率，预测杂交优势；并分析重要经济性状与遗传杂合度的关系，揭示杂种优势的分子遗传机理。本课题实施，将探索解决牡蛎杂交育种因长期缺乏可靠中间材料体系而影响杂种优势利用和杂种优势预测的科学问题。

香港巨牡蛎是我国华南沿海最重要的养殖双壳贝之一。本课题在我国华南沿海各主要地理分布群体的遗传背景分析基础上，1）筛选出四个遗传结构清晰、性状特点明显且群体间遗传差异显著的地理群体。2）采用家系选育、歧化选择、同质交配等方式对四个基础地理群体进行纯繁培育，聚合有利基因及连锁、增加优质高产基因频率,快速构建可用于高效杂交模式的基础材料体系。3)对经纯繁培育出的杂交基础群体采用双列杂交，分析育种值及各组合特殊配合力大小，为杂种优势预测及解释提供了直接的依据。4）同时，采用分子标记技术对各中间材料体系逐代分析遗传结构变化及群体间遗传结构差异，科学评估该杂交体系效率，预测杂交优势；并分析重要经济性状与遗传杂合度的关系，揭示杂种优势的分子遗传机理。本课题实施，基本解决了牡蛎杂交育种因长期缺乏可靠中间材料体系而影响杂种优势利用和杂种优势预测的科学问题。