Genotype x environment interaction as it relates to egg production in turkeys

牧童

Genotype x environment interaction as it relates to egg production in turkeys (Meleagris gallopavo)L. A. Case*,1, M. J. Kelly*, S. P. Miller* and B. J. Wood*, [size=-1]* Department of Animal and Poultry Science, University of Guelph, Guelph, Ontario, Canada; and Hybrid Turkeys, Suite C, 650 Riverbend Drive, Kitchener, Ontario, Canada [size=-1]1 Corresponding author: lcase@uoguelph.ca Genotype x environment (GxE) interactions can reduce the accuracy of a model to predict the performance of an animal and have an undesirable influence if not accounted for when estimating breeding values. Consequently, identification of these GxE is necessary when considering a turkey breeding program. Reranking based on the genetic prediction of turkey egg production, fertility, and hatchability in different seasons was indicative of a potential GxE interaction. Quantification of the GxE interactions was based on the genetic correlation estimated when traits were expressed in different seasons. Egg production was expressed as the percentage of days with an egg produced; fertility represented the proportion of hatched eggs that contained a fertile embryo; and hatchability was defined as the percentage of fertile eggs that produced a live bird. Variance components and heritability for egg production, fertility, and hatchability were estimated using ASReml. The heritability (h2) of egg production was calculated to be 0.32 for both lines with the phenotypic and genetic variance, 141.3 and 45.58 (percent days with egg produced)2 and 118.3 and 38.35 (percent days with egg produced)2 for female and male lines, respectively. The h2 estimates for fertility were 0.08 in both lines with and of 293.3%2 and 24.03%2, and 576.9%2 and 48.43%2 for female and male lines, respectively. The hatchability h2, and estimates were 0.09, 267.1%2, and 24.44%2, respectively, for the female line and 0.15, 582.2%2, and 90.01%2 for the male line, respectively. Based on an animal model, the variance components were used to calculate estimated breeding values for each trait. The annual fluctuation in estimated breeding values resulted in the need to evaluate egg number, fertility, and hatchability as 2 traits, summer and winter lay. The correlation between the 2 traits was less than unity (female line: regg production = 0.76, rfertility = –0.20, rhatchability = 0.75 and male line: regg production = 0.86, rfertility = 0.19, rhatchability = 0.68) suggesting a GxE interaction, and animals will significantly rerank in genetic predictions for these reproductive phenotypes in different seasons of lay. Egg production, fertility, and hatchability in turkeys could be considered as 2 distinct traits in an animal model based on season of lay. Key Words: egg production • fertility • genotype x environment interaction • hatchability • heritability • turkey

qdwelly

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jiangyunhe

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