Genet. Sel. Evol.
Volume 40, Number 5, September-October 2008
|541 - 551
|12 August 2008
Genotype by environment interaction for adult body weights of shrimp Penaeus vannamei when grown at low and high densitieAna M. Ibarra1 and R. Famula2
1 Aquaculture Genetics and Breeding Laboratory, Centro de Investigaciones Biolo' gicas del Noroeste S.C., Mar Bermejo 195, La Paz B.C.S. 23090, Mexico
2 Department of Animal Science, University of California Davis, 1 Shields Avenue, Davis, CA 95616, USA
Received 14 June 2007; accepted 1st April 2008; published online 12 August 2008
Abstract - Shrimp is one of few marine species cultured worldwide for which several selective breeding programs are being conducted. One environmental factor that can affect the response to selection in breeding programs is the density at which the shrimp are cultured (low-medium-high). Phenotypic plasticity in the growth response to different densities might be accompanied by a significant genotype by environment interaction, evidenced by a change in heritabilities between environments and by a genetic correlation less than one for a unique trait between environments. Our goal was to understand whether different growth densities affect estimates of those genetic parameters for adult body weight (BW) in the Pacific white shrimp (Penaeus vannamei). BW heritabilities were significantly different between environments, with the largest at high density. These differences resulted from both an increased additive genetic variance and a decreased environmental variance when grown at high density. The genetic correlation between BWs at the two environmental conditions was significantly less than one. Whereas these results might be suggestive for carrying out shrimp selective breeding for BW under high density conditions, further understanding of genetic correlations between growth and reproductive traits within a given environment is necessary, as there are indications of reduced reproductive fitness for shrimp grown at high densities.
Key words: Litopenaeus / heritability / body weight / density / genotype by environment interaction
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© INRA, EDP Sciences 2008