长牡蛎生长性状遗传力、遗传相关和表型相关分析

Analysis of heritability, genetic correlation and phenotypic correlation for growth trait in Pacific oyster(Crassostrea gigas)

为了查清乳山(RS)和崆峒岛(KTD)海域长牡蛎生长性状各指标的遗传力、遗传相关和表型相关,本实验通过部分因子交配设计和人工授精的方法建立家系,并在乳山和崆峒岛海域进行养殖。用混合线性模型分别计算RS和KTD海域188日龄、338日龄和474日龄长牡蛎生长性状各指标的遗传参数。结果发现:不同日龄长牡蛎生长性状各指标,在乳山海域的遗传力是0.28~0.55,为中高遗传力,在崆峒岛海域的遗传力是0.34~0.63,为高遗传力;与乳山海域相比,崆峒岛海域各指标的遗传力偏高。运用亲本模型,将日龄和地点作为固定效应,计算得到壳高、壳长、壳宽和湿重的遗传力分别为0.25±0.08、0.29±0.09、0.14±0.05和0.26±0.09。不同海域、不同日龄的遗传相关和表型相关结果各不相同,但各指标间均呈现正相关;总体来讲,性状间的遗传相关大于表型相关。实验结果有助于掌握山东半岛南北两侧长牡蛎生长性状的数量遗传学参数,为制定长牡蛎在该海域的选育技术路线提供数据支持。

Pacific oyster（Crassostrea gigas） has the characters of strong environmental adaptation, fast growth,delicious flavor and rich nutrition. C. gigas is the most widely cultivated aquaculture species, the highest production economic shellfish in the world. When carrying out genetic breeding of animals, genetic parameters play important role in such aspects： individual genetic evaluation, selection response prediction, best breeding scheme design and improving the efficiency of selective breeding. This study conducted the experiment at the both north and south sides of the Shandong Peninsula. Ru Shan（RS） area is the main market of oyster in Shandong Province. Through market research, about 90% of the oyster come from RS area in the winter market of Shandong Province. Kong Tong Dao（KTD） area is another main market of oyster in Shandong Province, which can have up to 50%–70% market share in spring and summer of Yantai aquatic market. Genetic parameters of different strains and in different environment will be different. Although the same genotype materials, when environmental contributions to phenotypic variation change, its genetic parameters will be changed. Strictly speaking, the genetic parameters of specific groups can only be applied to a particular environment. In order to improve the efficiency of selective breeding, obtaining important economic characters of heritability and genetic correlation of genetic parameters in specific environment is very important. So far, no report of genetic parameters in C. gigas has been found about RS and KTD area. In order to find out heritability, genetic correlation and phenotypic correlation of growth traits in C. gigas in RS and KTD areas, this study was carried out by partial factor mating design and artificial insemination method to establish the family, and the oyster families were bred in RS and KTD areas. The mixed linear model was used to estimate genetic parameters of growth traits of the RS and KTD areas at the age of188 days, 338 days and 474 days in C. gigas. The results show that the index of growth traits of C. gigas at different age, heritability in RS area was 0.28–0.55, which was medium to high heritability, heritability in KTD area was 0.34–0.63, which was high heritability. Compared with the RS area, heritability of growth trait in KTD area was height. By using the parent model, the age and location as fixed effects, and calculated heritability of the shell height（SH）, shell length（SL）, shell width（SW） and wet weight（WW）, which were： 0.25±0.08, 0.29±0.09,0.14±0.05 and 0.05±0.09. Genetic correlation and phenotypic correlation were varied at different areas and different age, but both correlations presented here were positive between each index. In general, the genetic correlation is higher than the phenotypic correlation between each index. Results of this study could provide data support of breeding route at both sides of north and south of Shandong Peninsula. The results also could help to obtain quantitative genetics parameter of growth trait in C. gigas in these areas.