The usefulness of triploid sib records for selection of diploid candidates in rainbow trout breeding programs for growth, processing traits and hypoxia tolerance
- 1INRAE
Abstract
This study investigates the benefits for rainbow trout selective breeding of using triploid performances rather than diploid ones. Its objectives were to estimate genetic parameters, assess genetic correlations between ploidy levels, and evaluate the gain in selection efficiency using triploid sib testing. The traits analysed were growth, carcass traits, fat content, and acute hypoxia tolerance using pedigree-based and genomic models. Results showed that diploids were heavier and longer than triploids at slaughter age. Triploids exhibited greater tolerance to acute hypoxia in this experiment, although the underlying mechanisms remain unclear. However, heritability estimates for most traits were similar between ploidy levels when genetic models correctly accounted for triploidy and the unequal maternal and paternal chromosome contributions. Incorrectly treating triploids as diploids substantially overestimated genetic variance and heritability values. Genetic correlations between diploid and triploid performances were high for all traits but varied from 0.60 to 0.98. Correlations were particularly high for carcass yield, fat-related traits and hypoxia tolerance indicating that selection based on diploid performance can efficiently improve these characteristics in triploid offspring. Conversely, correlations for body weight and length were lower, suggesting that evaluating triploid relatives could improve selection accuracy for growth. Overall, the findings support diploid-based selection as an effective strategy for improving triploid production traits, particularly carcass yield and flesh quality. Direct evaluation of triploid relatives may provide additional benefits for growth-related traits. The study highlights the importance of appropriate genetic and genomic models and recommends assessing the economic value of triploid performance testing for each target trait.
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BibTeX
@misc{roche2026usefulness,
title = {{The usefulness of triploid sib records for selection of diploid candidates in rainbow trout breeding programs for growth, processing traits and hypoxia tolerance}},
author = {J. Roche and L. Buisson and P. Patrice and Y. Francois and A. Desgranges and J. D'Ambrosio and P. Haffray and F. Phocas},
howpublished = {bioRxiv},
year = {2026},
month = oct,
doi = {10.64898/2026.10.18.759899},
url = {https://www.biorxiv.org/content/10.64898/2026.10.18.759899v1},
note = {CC BY-NC-ND},
}
RIS
TY - UNPB
TI - The usefulness of triploid sib records for selection of diploid candidates in rainbow trout breeding programs for growth, processing traits and hypoxia tolerance
AU - J. Roche
AU - L. Buisson
AU - P. Patrice
AU - Y. Francois
AU - A. Desgranges
AU - J. D'Ambrosio
AU - P. Haffray
AU - F. Phocas
PY - 2026
DA - 2026/10/18
PB - bioRxiv
DO - 10.64898/2026.10.18.759899
UR - https://www.biorxiv.org/content/10.64898/2026.10.18.759899v1
AB - This study investigates the benefits for rainbow trout selective breeding of using triploid performances rather than diploid ones. Its objectives were to estimate genetic parameters, assess genetic correlations between ploidy levels, and evaluate the gain in selection efficiency using triploid sib testing. The traits analysed were growth, carcass traits, fat content, and acute hypoxia tolerance using pedigree-based and genomic models. Results showed that diploids were heavier and longer than triploids at slaughter age. Triploids exhibited greater tolerance to acute hypoxia in this experiment, although the underlying mechanisms remain unclear. However, heritability estimates for most traits were similar between ploidy levels when genetic models correctly accounted for triploidy and the unequal maternal and paternal chromosome contributions. Incorrectly treating triploids as diploids substantially overestimated genetic variance and heritability values. Genetic correlations between diploid and triploid performances were high for all traits but varied from 0.60 to 0.98. Correlations were particularly high for carcass yield, fat-related traits and hypoxia tolerance indicating that selection based on diploid performance can efficiently improve these characteristics in triploid offspring. Conversely, correlations for body weight and length were lower, suggesting that evaluating triploid relatives could improve selection accuracy for growth. Overall, the findings support diploid-based selection as an effective strategy for improving triploid production traits, particularly carcass yield and flesh quality. Direct evaluation of triploid relatives may provide additional benefits for growth-related traits. The study highlights the importance of appropriate genetic and genomic models and recommends assessing the economic value of triploid performance testing for each target trait.
ER -