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Hayes B.J.,Australian Department of Primary Industries and Fisheries | Hayes B.J.,Nofima AS | Gitterle T.,CENIACUA | Gitterle T.,Akvaforsk | And 9 more authors.
Aquaculture Research | Year: 2010

There has been a highly detrimental impact of the white spot syndrome virus (WSSV) on black tiger shrimp (Penaeus monodon) aquaculture in India. Currently, no cost-effective measures are available for controlling the disease. One alternative is to improve WSSV resistance through a selective breeding programme for disease-resistant shrimp, provided that genetic variation exists for this trait. The aim of this study was to evaluate the evidence for genetic variation in resistance to WSSV in P. monodon sourced from Indian populations. Post-larval shrimp (n51950) from 54 full-sibling families were challenged with WSSV using WSSV-infected mince meat. The heritability was estimated using four different statistical models fitted to the resulting time to death data, including two linear models and two Weibull proportional hazard frailty models. None of the estimated heritabilities were significantly different from zero. We suggest three possible explanations for these results: there actually is very little variation between P. monodon inWSSVresistance and all individuals are highly susceptible to the disease; there is genetic variation in resistance to WSSV in P. monodon but we did not find it in our experiment because the level of challenge in the experimentwas too high to allow genetic differences to be expressed; the variation is due to mutations conferring resistance, which are at a low frequency in the population, and we did not sample a broad enough genetic base to capture these mutations. © 2010 Blackwell Publishing Ltd. Source

Krishna G.,Central Institute of Fisheries Education | Gopikrishna G.,Central Institute for Brackish Water Aquaculture | Gopal C.,Central Institute for Brackish Water Aquaculture | Jahageerdar S.,Central Institute of Fisheries Education | And 14 more authors.
Aquaculture | Year: 2011

Genetic parameters were estimated for growth and pond survival of Penaeus monodon using full-sib families from wild brood females collected from Tamil Nadu and Andhra Pradesh of the Indian coastline. The post larvae were reared, tagged, and thereafter communal-reared in two ponds. There was a moderate phenotypic correlation between stocking weight and harvest weight (0.39). A linear mixed model, when fitted to the harvest weight, revealed significant sex and pond effects and a heritability estimate of 0.27 ± 0.07. This estimate is likely to over-estimate the true heritability, as full-sib families were initially reared in separate tanks, although tagging weight was fitted as a covariate in an attempt to remove this effect. Correlation of family breeding values for harvest weight between the two ponds suggested little genotype × environment interaction. Heritability of pond survival was 0.21 ± 0.06, with unusually low levels of survival in the experiment, likely contributing to the high level of genetic variance observed. The correlation between family breeding values for harvest weight and pond survival was low (0.05) and not significantly different from zero. However, the correlation was not antagonistic, suggesting that P. monodon broodstock with high breeding values for both traits could be selected. © 2011 Elsevier B.V. Source

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