遗传选育对野生和养殖中华绒螯蟹蟹种形态学特征的影响

以野生和养殖蟹种及其选育后代作为研究对象,实验采用单因素方差分析、判别分析、主成分分析和聚类分析等方法对各组形态特征进行分析。结果显示,(1)野生和养殖群体原代(G0)雌雄个体分别有16和15个形态指标差异显著,而选育2代后36个形态学指标均无显著差异;(2)判别分析中野生和养殖G0的判别准确率高达93%~100%,而2群体G1和G2个体判别准确率仅为56.67%~76.67%,且G2判别率低于G1;(3)主成分散点图显示野生群体G0与G1、G2个体分别可以形成较集中的区域,而主成分分析难以区分养殖群体G0、G1和G2个体;(4)聚类分析将6种群蟹种分为2支,其中养殖群体G0、G1和G2与野生群体G1和G2聚为一支,而野生G0单独聚为一支。研究表明,长江野生和池塘养殖蟹种的形态学差异较大,但在选育过程中逐渐消失,最终与养殖群体趋于一致,因此形态学特征不能作为中华绒螯蟹良种选育的可靠指标。

Effects of selective breeding on the morphological characteristics of wild and cultured juvenile Chinese mitten crab (Eriocheir sinensis)

The morphology is an important criterion for the evaluation of carb breed quality of Eriocheir sinensis. High-quality carb breed were thought to possess patent rostral spine and verruca as well as relatively longer periopods, but it remains unclear whether these morphological characteristics can be stably inherited and be served as indicators for selective breeding of E. sinensis. Therefore, thirty-six morphological indices were used to evaluate the changes and difference of juvenile E. sinensis from pond-reared(PR) and wild-caught(WC) populations before and their offspring from the first generation (G1) and the second generation (G2) after the selective breeding programs; and the analysis methods included One-Way Analysis of variance, discriminant analysis, principal component analysis and cluster analysis for discrimination. The results showed that:(1) in One-Way Analysis of variance, there were significant differences between unselected PR and WC populations (G0) in the 16 and 15 out of 36 morphological indices for females and males respectively, and these differences disappeared gradually during selection so that no significant difference could be found in 36 morphological indices after selection for two generations (G2); (2) in discriminant analysis, the accuracy rate of discrimination were 93%-100% between unselected populations and this value decreased obviously after first and second generation of selection (G1 and G2), only 56.67%-76.67%; (3) in principal component analysis, only G0 individuals of PR and WC population could be divided into two independent groups by the first two principal components; in terms of WC populations, G0 individuals were separated from G1 and G2 individuals, and it is hard to distinguish G0, G1 and G2 individuals of PR population between each other either; (4) in cluster analysis, G0, G1 and G2 individuals of PR population clustered with G1 and G2 individuals of WC population while G0 of WC individuals clustered independently, whether females or males. In conclusion, although there was significant difference in many morphological indices between WC and PR juveniles, these differences disappeared gradually during the selection process, and the similar morphological indices were found in the juveniles of G2 between PR and WC populations. Therefore, morphological characteristics could not be used as effective indices for the selective breeding of E. sinensis.