虹鳟(Oncorhynchus mykiss)选育群体主要体尺性状表型和遗传相关分析

以虹鳟(Oncorhynchus mykiss)优良品系选育群体作为试验群体,采用单性状动物模型估计头长、体长、体高、体厚、尾柄长、尾柄高、背吻距、背鳍基长等8个主要体尺性状的遗传力。结果显示,上述8个性状的遗传力在0.131—0.313之间,多为中等或偏低遗传力,其中背鳍基长遗传力最低,为0.131±0.039,体高遗传力最高,为0.313±0.086。采用皮尔逊相关法估计上述性状之间的表型相关,结果显示,上述性状间表型相关变化范围为0.016—0.815。采用两性状动物模型估计上述性状间的遗传相关,结果表明,上述性状间遗传相关变化范围为0.065—0.866。在本研究中,比较分析表型和遗传相关结果发现,虽然体厚与尾柄长的表型相关最低,仅为0.016,相关性不显著(P0.05),但是遗传相关为0.247,似然比检验(likelihood ratio test,LRT)统计分析达到显著水平(P0.05)。体厚与背鳍基长的表型相关为0.647,t检验达到显著水平(P0.05);但遗传相关仅为0.305,LRT统计分析未达到显著水平(P0.05)。上述结果说明,在该群体中各体尺性状的表型相关和遗传相关水平不完全相同,在设计育种方案时应综合考虑各个性状间的表型相关及遗传相关。

ESTIMATION OF PHENOTYPIC AND GENETIC CORRELATION FOR BODY MEASUREMENT TRAITS IN A SELECTIVE BREEDING POPULATION OF RAINBOW TROUT (ONCORHYNCHUS MYKISS)

The second generation (G2) of a rainbow trout selective strain population was used as the experimental population. This strain was being selectively bred in the Heilongjiang River Fishery Research Institute (HRFRI), the Chinese Academy of Fishery Sciences (CAFS). Single-trait animal model was used to estimate the heritability of eight body measurement traits, including head length, body length, body height, body thickness, caudal peduncle length, caudal peduncle height, and the distance from dorsal ?n to the snout and dorsal ?n base length. The results show that the heritabilities of these measurement traits ranged from 0.131 to 0.313, mainly at middle or low level. The heritability of dorsal fin base length was the lowest one at 0.131 ± 0.039, and that of body height the highest at 0.313 ± 0.086. The genetic correlations between each pair of the above traits were estimated by using two-trait animal model, and phenotypic correlations between each pair of these traits were estimated by using Pearson correlation method. The results show that the genetic correlations ranged from 0.065 to 0.866, and the phenotypic correlations from 0.016 to 0.815. In addition, we found that the phenotypic correlation between body thickness and caudal peduncle length was the lowest, with a value of only 0.016, and did not reach significant level (P > 0.05). However, the genetic correlation between them was 0.247, which is significant (P < 0.05) as indicated in likelihood ratio test (LRT) statistics. The phenotypic correlation between body thickness and the dorsal ?n base length was 0.647, reaching a significant level (P < 0.05) by t-test, but the genetic correlation between them was only 0.305, which is not significant (P > 0.05) indicated in LRT statistics. Therefore, not all of these body measurement traits were in similar levels of phenotype and genetic correlation in this experimental population. Mistakes may occur when only phenotypic or genetic correlation is considered in a design of a breeding program. The results could provide useful knowledge for selective breeding in body measurement traits of rainbow trout (Oncorhynchus mykiss).