Abstract Pacu (Piaractus mesopotamicus) belongs to the main native fish group of the continental aquaculture in South America. However, breeding programs are not available for this species. The estimation of parameters for different traits and in different environments are needed to set up optimized breeding programs Therefore, the objectives of this study were to estimate genetic parameters, to evaluate genotype by environment (GxE) interaction, and to identify morphotypes for growth traits in pacu, using an experimental data of a pedigreed population in Brazil. Data from 1380 individuals corresponding to 48 full-sib families for ten growth traits (initial weight, final weight, average daily gain, total length, standard length, head length, pelvis length, total height, head height, height at the posterior region) were evaluated in two distinct environments (breeding nucleus: env1; commercial fish farm: env2) at 15 months old. The average of final weight was 591.90 ± 274.60 g in env1 and 1035.80 ± 270.00 g in env2. The heritability estimates were registered as moderate/high, which ranged from h2 = 0.27 ± 0.12 to 0.74 ± 0.19. Correlation values between the growth traits were positive and low-high, ranging between 0.32 ± 0.04 to 0.96 ± 0.10 (phenotypic) and 0.33 ± 0.10 to 0.98 ± 0.01 (genetic). The genetic correlations between final weight and morphometric traits were significant and high (ranging from 0.70 ± 0.10 to 0.88 ± 0.05). Our results also revealed different morphotypes patterns for pacu (elliptical and rounded). GxE interaction was considered low for all traits between the two environments (correlation values of 0.80 ± 0.34 to 0.98 ± 0.23). In conclusion, our results suggest that growth traits can be incorporated into the breeding objective in pacu and superior animals evaluated at the breeding nucleus are predicted to be superior at the commercial environment. Moreover, selection can be driven according to the desired morphotype in pacu.

中文翻译：

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通过环境相互作用和遗传参数确定新热带鱼类 pacu（Piaractus mesopotamicus）生长性状的基因型

摘要 Pacu（Piaractus mesopotamicus）属于南美洲大陆水产养殖的主要本土鱼类群。但是，该物种没有育种计划。需要估计不同性状和不同环境的参数以建立优化的育种程序 因此，本研究的目的是估计遗传参数，通过环境（GxE）相互作用评估基因型，并确定生长性状的形态型pacu，使用巴西血统种群的实验数据。来自 1380 个个体的数据，对应于 48 个全同胞家族的 10 个生长性状（初始体重、最终体重、平均日增重、总长度、标准长度、头长、骨盆长度、总高度、头高、在 15 个月大时，在两种不同的环境（繁殖核心：env1；商业养鱼场：env2）中评估了后部区域的高度。最终重量的平均值在 env1 中为 591.90 ± 274.60 g，在 env2 中为 1035.80 ± 270.00 g。遗传力估计值为中/高，范围从 h2 = 0.27 ± 0.12 到 0.74 ± 0.19。生长性状之间的相关值为正和低-高，范围在 0.32 ± 0.04 至 0.96 ± 0.10（表型）和 0.33 ± 0.10 至 0.98 ± 0.01（遗传）之间。最终体重和形态特征之间的遗传相关性显着且很高（范围从 0.70 ± 0.10 到 0.88 ± 0.05）。我们的结果还揭示了 pacu（椭圆形和圆形）的不同形态类型模式。对于两个环境之间的所有特征，GxE 交互被认为很低（相关值为 0。80 ± 0.34 至 0.98 ± 0.23)。总之，我们的结果表明，可以将生长性状纳入 pacu 的育种目标中，并且预测在育种核心评估的优良动物在商业环境中更优越。此外，可以根据 pacu 中所需的形态类型来驱动选择。