近交对三疣梭子蟹若干经济性状衰退的影响

摘要

We quantified the effects of inbreeding on growth, survival and the yield which related to survival of domesticated Portunus trituberculatus for the inclusion in selective breeding programs of the future. To make this assessment, we systematically bred six inbreeding generations with known parentage. During the production sea-son, we assessed the growth, survival and yield, with One-Way ANOVA statistical analysis. The experimental results show that, compared with the F1 inbreeding generation by every per 10%inbreeding coefficient increasing, the estimated inbreeding depression coefficient was-2.4%--5.1%in overall carapace width,-0.8%--3.5%in body weight, -34.4%- -69.9% in overall survival and -14.1%- -35.4% in the yield which related to survival. And compared with the F1 inbreeding generation, the F3 did not appear inbreeding depression phenomenon, no matter in growth, survival and the yield which related to survival, and F2, F4, F5 and F6 all appeared different de-gree of inbreeding depression compared with F1 in growth, survival and the yield which related to survival, and had a high and significant effect between six inbreeding generations (P<0.05). At the harvest time, we analyzed uniformity and found that the variation coefficient of F6 inbreeding generation is the largest in six inbreeding gen-erations, means the uniformity of F6 inbreeding generation is the worst in six inbreeding generations, but the dif-ference with other each generation is not significant (P>0.05). The consistency in direction of the inbreeding de-pression coefficients for six generations lends to support to the hypothesis that inbreeding reduces growth, survival and the yield which related to survival, even though the coefficients were not statistically significant due to high variability among animals. These results suggest that inbreeding should be avoided in crab breeding programs.%本实验通过定向交尾技术构建了三疣梭子蟹(Portunus trituberculatus)全同胞交近交家系。在生长季节，通过对相关形态学指标的测定，对F1-F6家系的生长、存活以及与存活相关的产量进行评估，用单因素方差分析进行统计学分析。实验结果表明，相比于 F1家系，近交系数每增加10%，就会引起全甲宽-2.4%~-5.1%的衰退，体质量-0.8%~-3.5%的衰退，存活-34.4%~-69.9%的衰退，与存活相关的产量-14.1%~-35.4%的衰退，可以发现全甲宽和个体平均体质量的衰退程度较低，存活以及与存活相关的产量的衰退程度较高。近交系数为37.5%的 F3无论在生长、存活还是产量上都没有出现近交衰退，但150日龄时各个指标的差异系数明显较 F1、F2大，表明其整齐度比F1、F2差； F2、F4、F5和 F6相比于 F1在生长、存活和与存活相关的产量上都出现了不同程度的近交衰退，差异显著(P<0.05)；在150日龄收获时，分析各代家系的整齐度发现， F6的变异系数最大，整齐度最差，但与其他各代的差异并不显著(P>0.05)。6代家系近交衰退的一致性表明近交确实降低了三疣梭子蟹的生长、存活和产量，尽管一些衰退的差异性并不显著。在实际的养殖生产中，应当尽量避免近交的发生，近交应当在动物育种工作需要时才使用，只适宜在培育新品种、建立新品系、种群提纯与保纯的过程中采用，在无目的或目的性不明确的情况下应避免近交。本研究通过观察连续近交的三疣梭子蟹在生长、存活及相关的产量方面的变化，旨在为三疣梭子蟹选择育种的研究与生产提供数据支持。