大口黑鲈北方亚种、佛罗里达亚种及其杂交子代的生长和形态差异分析

以大口黑鲈北方亚种和佛罗里达亚种为亲本,建立了北方亚种自交N(北方亚种♀×北方亚种♂)、佛罗里达亚种自交F(佛罗里达亚种♀×佛罗里达亚种♂)、正交子代NF(北方亚种♀×佛罗里达亚种♂)和反交子代FN(佛罗里达亚种♀×北方亚种♂)4个试验群体,并对其生长性能和形态学差异进行了比较。N、NF和FN的生长性能比较结果表明,在90～152日龄期间,3个试验群体生长速率差别不大,在152日龄后大口黑鲈北方亚种的生长速度明显快于两杂交子代。可数性状的分析结果表明,4个试验组在腹鳍、臀鳍硬棘、鳃耙和脊椎骨上均无差异;正反交子代与两亲本在背鳍条、胸鳍条、臀鳍条、尾鳍条、侧线上鳞、侧线下鳞的数量上均达到极显著差异(P0.01)。可量性状和框架结构数据的聚类分析结果表明,N和F聚为一支,NF和FN聚为一支,然后这两支再汇聚;主成分分析概括出方差贡献率较大的3个主成分,累积贡献率为71.44%,主成分1主要反映鱼体框架的变化,方差贡献率为54.90%,主成分2和主成分3主要反映鱼的头部、背部和尾部的形态变化,方差贡献率分别为11.21%和5.33%。在35个测量参数中挑选11个对判别贡献较大的参数建立4个群体的判别函数,判别准确率为83.90%～100.00%。研究结果为杂种大口黑鲈的鉴定、育种及养殖提供了科学依据。

Growth and morphological characteristics comparison of northern largemouth bass, Florida largemouth bass and their reciprocal hybrids

Based on northern largemouth bass and florida largemouth bass, four populations including selfing of N(Micropterus salmoides salmoides ♀×M. s. salmoides♂) and F(M. s. floridanus ♀×M. s. flori-danus♂), direct cross NF(M. s. salmoides♀×M. s. floridanus♂) and FN(M. s. floridanus♀×M. s. sal-moides♂) were established. Further comparative analysis of growth and morphological characteristics were carried out between parents and their reciprocal hybrids. The results were as follows. The growth rates had no difference between N, NF and FN on 152nd day. After 152 days the northern largemouth bass grew more rapidly than two hybrids. As meristic characters, the numbers of soft ray of pelvic, spine of anal fin, gill raker and vertebra were consistent in these four populations, and the chi-square analysis of meristic characters showed highly significant differences between parents and hybrids in soft ray of dorsal, soft ray of pectoral, soft ray of anal fin, soft ray of tail fin, scales above lateral line and scales below lateral line. The results of cluster analysis have revealed that the morph metric characters of N and F were much closer, the same to the reciprocal hybrids groups. Three principal components with accumulative variance per-centage 71.44% were summarized in principal component analysis. The principal components 1, 2 and 3 reflected the morphological variations of frame, head and caudal peduncle, with the variance percentage being 54.90%, 11.20% and 5.33%. In discriminant analysis, 11 parameters were selected from 35 measured parameters to establish discriminant functioned of the populations. Discriminant accuracy was 83.90%—100.00%. This study would be beneficial to the identification, breeding and aquaculture of largemouth bass.