Quantitative genetic parameter estimates for size and growth rate traits in Pacific white shrimp, Penaeus vannamei (Boone 1931) when reared indoors |
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| Authors: | Carlos I Pérez-Rostro & Ana M Ibarra |
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| Institution: | Centro de Investigaciones Biológicas del Noroeste, S.C. Aquacultural Genetics Laboratory, A.P. 128. La Paz, B.C.S. 23000, México |
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| Abstract: | Heritabilities of size traits and growth rate traits, as well as genetic, phenotypic and environmental correlations were estimated at three ages for a captive population of Pacific white shrimp (Penaeus vannamei) grown indoors. A covariate, mean size or mean growth rate during early growth in individual tanks before tagging and mixing, was introduced in the analyses to reduce the error caused by unique previous growth conditions on variance components. Heritabilities of size traits increased with age, with the h2 for TL, AL, TWt and Wi1AS being 0.15, 0.20, 0.20 and 0.22, respectively, at 17 weeks, increasing to 0.28, 0.33, 0.34 and 0.35 at 29 weeks of age. Heritabilities of growth rate traits estimated between consecutive growth periods decreased from the first (h2 for ΔTL 0.65, ΔAL 0.71, ΔTWt 0.63 and ΔWi1AS 0.84) to the second period (h2 for ΔTL 0.34, ΔAL 0.50, ΔTWt 0.54 and ΔWi1AS 0.52). Phenotypic correlations were always larger than genetic correlations for both, size and growth rate traits. Genetic correlations between size traits within age were high (rG >0.95), but those between the same size trait at different ages decreased as the age difference increased in spite of a consistently high environmental correlation (rE 0.80–0.85) between the same trait at different ages. Phenotypic and genetic correlation's between the same growth rate trait at the two different growth periods evaluated were negative or zero (rG TL –0.26, AL –0.24, Wi1AS 0.00) with the exception of total weight (rG TW 0.35) and the environmental correlations between growth periods were also low (rE 0.13–0.32). |
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| Keywords: | Penaeus vannamei heritability size growth genetic correlation environmental correlation covariate |
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