Red tilapia is a phenotype with potential value to the tilapia industry due to its attractive skin coloration. However, the presence of black blotches scattered on the body makes these fish less valuable than blemish-free red fish. The correlation between the degree of blotching and other economic traits is important for selective breeding programs including high-performance red fish without black blotches. Therefore, this study aimed to assess the magnitude and direct and indirect effects of blotching in crossbred red tilapia on the growth rate and body measure traits using path analysis methodology. Six genetic groups were evaluated in terms of body measurements, body weight rate, and proportion of black blotching over 250 days of growth: Chitralada and Red-Stirling; crossbred F1—♀ Red-Stirling × ♂ Chitralada and ♀ Chitralada × ♂ Red-Stirling, and the introgressive crossbreeding—♀ CR × ♂ Chitralada and ♀ Chitralada × ♂ CR (C × CR). All variables showed high and positive linear correlations. Individuals with black blotches had lower coefficients of correlation with other variables (body weight and measurements); the direct and indirect effects are near zero. The path analysis indicated a lack of genetic correlation between the degree of black blotches and the economic traits of red tilapia. This facilitates the development of high growth performance red fish with blotched-free reddish skin.

中文翻译：

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通过路径分析方法对杂交红罗非鱼中黑色斑点的定量分析及其对性能特征的影响。

红色罗非鱼是一种具有吸引力的皮肤颜色，对罗非鱼产业具有潜在价值的表型。但是，散布在身体上的黑色斑点使这些鱼的价值不如无瑕疵的红色鱼。斑点程度与其他经济性状之间的相关性对于选择性育种计划（包括没有黑色斑点的高性能红鱼）非常重要。因此，本研究旨在使用路径分析方法评估杂交红罗非鱼的斑点的数量以及对生长速度和身体测量特征的直接和间接影响。对六个基因组进行了身体测量，体重比率和生长250天后黑色斑点的比例评估：Chitralada和Red-Stirling；杂交F1-♀Red-Stirling×♂Chitralada和♀Chitralada×♂Red-Stirling，和无性繁殖-CR×Chitralada和Chitralada×CR（C×CR）。所有变量均显示出高线性正相关。黑色斑点的个体与其他变量（体重和测量值）的相关系数较低；直接和间接影响几乎为零。路径分析表明，黑斑点的程度与红罗非鱼的经济性状之间缺乏遗传相关性。这促进了具有无斑点的微红皮肤的高生长性能红鱼的发展。直接和间接影响几乎为零。路径分析表明，黑斑点的程度与红罗非鱼的经济性状之间缺乏遗传相关性。这促进了具有无斑点的微红皮肤的高生长性能红鱼的发展。直接和间接影响几乎为零。路径分析表明，黑斑点的程度与红罗非鱼的经济性状之间缺乏遗传相关性。这促进了具有无斑点的微红皮肤的高生长性能红鱼的发展。