Effect of ploidy on the mortality of Crassostrea gigas spat caused by OsHV‐1 in France using unselected and selected OsHV‐1 resistant oysters |
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| Authors: | Lionel Dégremont Christophe Ledu Elise Maurouard Max Nourry Abdellah Benabdelmouna |
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| Affiliation: | 1. SG2M, LGPMM, Ifremer, La Tremblade, France;2. SG2M, LSPC, Ifremer, Bouin, France |
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| Abstract: | The effect of ploidy on the mortality of Crassostrea gigas spat caused by the ostreid herpesvirus (OsHV‐1) genotype μVar was investigated at five sites along the Atlantic coast in France in 2011. Sibling diploids and triploids were produced using either unselected or selected OsHV‐1‐resistant oysters. No significant interactions were found between the factors of environment, genotype and ploidy at the endpoint dates. The mean mortality rates at the sites were 62% and 59% for diploids and triploids, respectively, and the two rates were not significantly different. The mean mortality rates were 33% and 32% for sibling diploids and triploids, respectively, when OsHV‐1‐resistant parents were used and 91% and 85%, respectively, when unselected parents were used. The results were confirmed through other broodstocks tested in 2013. Our study is the first to clearly show that mortality related to OsHV‐1 is similar between diploids and triploids in C. gigas when the same germplasm is used for both ploidy. Furthermore, OsHV‐1 resistance was not substantially altered by triploidization, indicating that the achieved selective breeding of diploid oysters for OsHV‐1 resistance can be translated into improved survival in triploids. |
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| Keywords: | diploid triploid mortality
Crassostrea gigas
ostreid herpesvirus OsHV‐1 |
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