Assessment of environmental descriptors for studying genotype by environment interaction

摘要: Abstract Access to individual performance records opens up possibilities for treatment of genotype by environment interaction in international genetic evaluations. The ability distinguish similar from dissimilar environments is thus important. Reaction norms were used this study evaluate several variables their suitability classify production studies on interaction. describe the phenotypic expression a as function environment, and can be modelled random regression environmental descriptors. Fifteen that measure aspects management, composition climate computed herd level. Suitability each variable detect was assessed through likelihood ratio tests significant linear or quadratic terms. First lactation approximately 40 000 Guernsey cows four countries (Australia, Canada, USA Republic South Africa) used. Variables with effect were: size, within-herd standard deviation yield, peak milk persistency, days production, calving pattern, age at first calving, rate maturity, annual rainfall. Genetic correlation between extreme rainfall lower than 0.91, indicating re-ranking animals may occur.