A review of genotype‐by‐environment interaction and micro‐environmental sensitivity in aquaculture species

Abstract

Generating breeding programmes that effectively improve farmed fish performance across multiple environments and make fish more uniform within production environments would aid farmers to produce food under diverse environments. We review genotype-by-environment interaction leading to re-ranking of genotypes across environments, that is non-unity genetic correlation between traits measured in different environments, and micro-environmental sensitivity leading to a change in environmental variance of a trait. A quantitative review across 38 species showed that (i) genotype-by-environment interaction studies are lacking for many economically important traits. (ii) Re-ranking is moderate for growth (average genetic correlation = 0.72) and survival (average genetic correlation = 0.54). Significant re-ranking is of concern because selection in a nucleus leads to lower genetic responses in commercial environments compared to a case when re-ranking does not exist. (iii) Re-ranking is weak for age-at-sexual-maturity and fish appearance (average genetic correlation = 0.86), implying that genetic improvement in one environment is expected to be effective in the other environments. Future research should provide guidelines for how to account for genotype-by-environment interaction when collecting data, estimating breeding values and optimising the structure of the breeding programme. (iv) Coefficient of genetic variation for sensitivity against unknown micro-environmental factors within a single environment for body weight is high. Hence, genetic improvement towards less sensitive fish, resulting in more uniform production, is possible, but a large number of relatives with phenotypes is needed for obtaining moderate accuracy of selection. This review elucidates needs for further research on genotype-by-environment interaction and micro-environmental sensitivity in economically important traits and species.

Future directions in breeding for disease resistance in aquaculture species

“…An additional challenge for breeding programmes of many aquaculture species is genotype by environment interaction, in which the performance of the selected animals can vary markedly across diverse production environments (e.g. in tilapia breeding; Sae-Lim et al, 2016). This results in reranking of genotypes across environments and effectively reduces the overall response to selection within a breeding programme (Sae-Lim et al, 2016).…”

“…in tilapia breeding; Sae-Lim et al, 2016). This results in reranking of genotypes across environments and effectively reduces the overall response to selection within a breeding programme (Sae-Lim et al, 2016).…”

“…based on family selection with sib-testing), improving response to selection in multiple environments will be a major goal. This will be particularly relevant for species such as tilapia (especially Nile Tilapia, Oreochromis niloticus), in which major breeding programmes are underway, and stock is typically disseminated to several countries and diverse farming systems (Sae-Lim et al, 2016;Omasaki et al, 2016). Therefore, it is important to quantify and incorporate G × E interaction when optimising a breeding programme for these species and the high fecundity may facilitate trait recording in multiple environments (Sae-Lim et al, 2016).…”

Estimating genetic parameters and genotype-by-environment interactions in body traits of turbot in two different rearing environments

“…The presence of a re-ranking effect can change the ranking of genotypes in different environments (Sae-Lim et al, 2015). The presence of a reranking effect was determined by the significant difference from unity in the genetic correlations across environments.…”

Genetics of inherited variability : Increasing uniformity by reducing competition

“…We analyzed within-family variance of harvest weight, body length, depth, and width, by applying a double hierarchical generalized linear models (DHGLM) to individual trait values (Rönnegård et al, 2010). In addition to quantifying genetic variation in inherited variability of those traits, we also looked into possibilities of Mulder H, Kause A (2015). A review of genotypeby-environment interaction and micro-environmental sensitivity in aquaculture species.…”