星突江鲽和石鲽正反杂交种的形态变异分析

对星突江鲽(Platichthys stellatus)、石鲽(Kareius bicoloratus)及其正反杂交种的形态特征进行了测定与分析。结果显示,正交种(星突江鲽♀×石鲽♂)和反交种(石鲽♀×星突江鲽♂)左眼型比例分别为66.9%和57.3%,介于星突江鲽(84.7%)和石鲽(0%)之间;正反杂交种体表未见似石鲽的长骨板样结构,在此大致位置处仅分布有星突江鲽体表相似的鳞片;杂交种的背鳍、臀鳍及尾鳍上均有比星突江鲽偏小、颜色偏淡的条纹,但侧线均与母本相似,正交种在胸鳍末端处弯曲,而反交种近似直线形;两杂交种可数性状的杂种指数平均值分别为20.73和20.76,可量性状的杂种指数平均值分别为27.16和26.47。卡方检验和聚类分析结果表明两杂交种的性状总体上偏向于母本;利用判别分析构建了4种鱼的判别公式,综合判别准确率达到97.50%;主成分分析显示,提取的4个主成分对总变异的累积贡献率为82.562%,主成分1对主成分3的散点图显示两杂交种在形态差异上独立于星突江鲽和石鲽。研究表明:星突江鲽与石鲽的正反杂交种在眼睛位置、鳞片和鳍的形态特征上更倾向于星突江鲽,而侧线、可数、可量性状则更多地遗传了母本的形态特征。本研究旨为星突江鲽、石鲽及其正反杂交种的形态判别和亲缘关系鉴定以及杂交选育提供理论依据。

Morphological variations analysis of reciprocal hybrids from Platichthys stellatus and Kareius bicoloratus

Morphological variations inPlatichthys stellatus,Kareius bicoloratus, and their reciprocal hybrids were measured and analyzed. The results showed that the ratios of left eye type in the obverse hybrid (P. stellatus♀×K. bicoloratus♂) and inverse hybrid (K. bicoloratus♀×P. stellatus♂) were 66.9% and 57.3%, respectively, which was between that ofP. stellatus(84.7%) and K. bicoloratus(0). The scales on the reciprocal hybrids were distributed similarly to those onP. stellatusand on the equivalent body positions where bony plates occurred onK. bicolora-tus. The reciprocal hybrids had dorsal, anal, and caudal finstripes similar to those ofP. stellatus, but they were smaller and more lightly colored. The lateral lines of the obverse hybrid andP. stellatusbent at the end of the pectoral fin, whereas the lateral lines of the inverse hybrid andK. bicoloratus were approximately linear. The av-erage hybrid meristic character index values of the two hybrids were 20.73 and 20.76, indicating that their meristic characters tended to be more similar to those of their female parents, as shown by the chi-square analysis. Among 11 metric character ratios, most of the metric characters were not different (P>0.05) between the hybrids and their female parents, and the average hybrid index values of the two hybrids were 27.16 and 26.47, indicating that their metric characters tended to be more similar to those of their female parents, as shown by the cluster analysis. Four discriminant functions were established in the discriminatory analysis. Average discriminant accuracy was 97.50%, indicating that the discriminant effect was ideal. Four principal components were constructed by factor loadings in the principal component analysis, and the cumulative contributing proportion was 82.562%. Scatter plots showed that the morphological differences between the two hybrids were independent of P. stellatus and K. bicoloratus. Therefore, a multivariate analysis of meristic and metric characters could be useful to identify and distinguish the morphological variations among P. stellatus, K. bicoloratus, and their reciprocal hybrids. These results indicate that the reciprocal hybrids between P. stellatus and K. bicoloratus resembled P. stellatus in eye position and scale and fin morphological characteristics and resembled their female parents in the lateral line and meristic and metric characters. The results will help discriminate the morphological characters and determine the genetic relationships between P. stellatus, K. bicoloratus, and their reciprocal hybrids and allow for breeding excellent hybrids.