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The effect of different levels of management on the assessment of differences between varieties of chickens. II. Egg production, mortality and egg weight

Published online by Cambridge University Press:  02 September 2010

J. C. Bowman  and
J. C. Powell
J. C. Bowman
Affiliation:
Research Division, Thornber Bros., Ltd., Mytholmroyd, Halifax
J. C. Powell
Affiliation:
Research Division, Thornber Bros., Ltd., Mytholmroyd, Halifax
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1. The data relating to 16 multi-location trials involving several varieties of egg-laying chickens per trial have been analysed to obtain estimates of variety × location (genotype-environment) interactions for rearing and laying mortality, hen-month and hen-housed egg production and 32-week egg weight. Significant interactions were found in about a third of the trials for all five traits though in only two cases did the interaction variance account for more than 20% of the total variance.

2. Genetic correlations for varieties between locations have been calculated as 0·49 for rearing mortality, 0·50 for laying mortality, 0·72 for hen-month production, 0·76 for hen-housed production and 0·91 for egg weight. These are in close agreement with previous published estimates.

3. The between-and within-variety components of variance have been calculated for each trait on each location separately. The regressions within trials and pooled values of the components on the mean level of all varieties on the location have been calculated. For hen-month production the pooled regres-son of the within-variety component on mean was negative, whilst for all other traits the pooled regressions were positive. The pooled regressions of the between-variety components on mean were all positive. It is suggested that this information indicates that comparison of varieties for single traits should be carried out on locations favourable for maximum expression of the trait. The difficulties which variety comparisons, for several traits having different optimum management regimes, would cause and the need for a more intensive investigation of the conditions conducive to genotype-environment interactions are stressed.

Type
Research Article
Information
Animal Production , Volume 6 , Issue 2 , June 1964 , pp. 195 - 205
Copyright
Copyright © British Society of Animal Science 1964

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References

REFERENCES

Abplanalp, H. & Menzi, M., 1961. Genotype and environment interactions in poultry. Brit. Poult. Sci., 2: 71.Google Scholar
Bowman, J. C., Jones, R. H. & Knight, D. W., 1964. Lighting techniques for the domestic fowl. 4. Experiments 1961–62. Brit. Poult. Sci. (In press.)Google Scholar
Bowman, J. C. & Powell, J. C., 1962. The effect of different levels of management on the assessment of differences between varieties of chickens. 1. Eight-week body weight. Anim. Prod., 4: 319.Google Scholar
Comstock, R. E. & Moll, R. H., 1963. Genotype-environment interactions. In Symposium Statistical Genetics and Plant Breeding. Publ. nat. Res. Coun. nat. Acad. Sci. (Wash.), no. 982: 164.Google Scholar
Dickerson, G. E., 1961. Effectiveness of selection for animal improvement. In Germ Plasm Resources. Publ. Amer. Ass. Advanc. Sci., no. 66: 161.Google Scholar
Dickerson, G. E., 1962. Implications of genetic-environmental interaction in animal breeding. Anim. Prod., 4: 47.Google Scholar
Falconer, D. S., 1952. The problem of environment and selection. Amer. Nat., 86: 293.CrossRefGoogle Scholar
Hull, P. & Gowe, R. S., 1962. The importance of interactions detected between genotype and environmental factors for characters of economic significance in poultry. Genetics, 47: 143.CrossRefGoogle ScholarPubMed
Hutt, F. B., 1961. Genetic variation in the utilization of ribofiavin, thiamine and other nutrients. Ann. N. Y. Acad. Sci., 91: 659.CrossRefGoogle ScholarPubMed
McBride, G., 1958. The environment and animal breeding problems. Anim. Breed. Abstr., 26: 349.Google Scholar
McBride, G., 1960. Poultry husbandry and the peck order. Brit. Poult. Sci., 1: 65.CrossRefGoogle Scholar
Powell, J. C. & Bowman, J. C., 1964. An estimate of maternal effects on early growth characteristics and their effect upon comparative tests of chicken varieties. Brit. Poult. Sci., 5: 121.CrossRefGoogle Scholar
Robertson, A., 1959. The sampling variance of the genetic correlation coefficient. Biometrics, 15: 469.CrossRefGoogle Scholar