Genotype by type of housing interaction in populations of white Leghorns under reciprocal recurrent selection

Krosigk, C. M. Von; Pirchner, F.

doi:10.1080/00071667408416077

Cited by 4 publications

(2 citation statements)

References 11 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In addition to chance, these differences may be caused by bias in prediction or in estimated environmental trends. Predicted and estimated genetic changes for two generations of response to reciprocal recurrent selection in White Leghorn strains for multiple objectives were presented by von Krosigk et al (1973). Their results showed good agreement between predicted and estimated response, although estimated response may have been biased by relaxed selection effects.…”

Section: Resultsmentioning

confidence: 91%

Effectiveness of Progeny Test Index Selection for Field Performance of Strain-Cross Layers

1981

View full text Add to dashboard Cite

Selection for egg production and egg quality traits in two sets (TX1 and TX2) of pedigreed strain-cross White Leghorns was based on strain-cross progeny performance averaged over field environments. Retrospect index weightings, selection intensities, and genetic parameters were used to predict genetic responses in TX1 and TX2 for a 5-year period. Predicted genetic responses were compared with realized genetic responses.Retrospect index weightings for 13 component traits showed less emphasis on early mortality (EMORT) and adult mortality (AMRT) and more emphasis on Haugh units and early shell texture than was intended. Selection intensity was about 1.5 o for males in male lines and about 1.0 o for females and males in female lines and for females in male lines. Average intensity of selection was 20% greater for retrospect than for intended selection index. Average intensity of selection among 3-year-old parents was no greater than that among 2-year-old parents, because 3-year-old parents had lower egg production, reduced fertility, and greater mortality.Predicted yearly change was in the desired direction for all traits except for a slightly negative predicted change in specific gravity. Predicted change in economic value (ECON) was $.09 for TX1 and $.12 forTX2. Most predicted change in ECON was due to traits affecting egg numbers (EGGS). Predicted changes in EGGS were 1.83 for TX1 and 2.33 for TX2.Estimated genetic changes were $.21 and 4.95 eggs for TX1 and $.21 and 5.00 eggs for TX2. Significant or near significant differences between predicted and estimated genetic changes indicated that EMRT, AMRT, egg weight, EGGS, and ECON changed more favorably than predicted and that excitability and blood spots changed less favorably than predicted. (

show abstract

Section: Resultsmentioning

confidence: 91%

Effectiveness of Progeny Test Index Selection for Field Performance of Strain-Cross Layers

1981

View full text Add to dashboard Cite

show abstract

“…As is typical for commercial breeding programmes, there is no unselected control population or negative selection line to study cumulative rates of genetic improvement, but improvement in the commercial cross has been estimated from repeat matings (Krosigk et al, 1972) and relative to other commercial strain crosses based on random sample test data (Flock, 1988). The primary reasons for changing from strict RRS to MRRS was lack of information with regard to the pure line: cross line genetic correlations, which require testing pure line and cross line sire progeny in the same environment.…”

Section: Methodsmentioning

confidence: 99%

Cumulative inbreeding in commercial White Leghorn lines under long‐term reciprocal recurrent selection

Ameli¹,

Flock

Glodek³

1991

British Poultry Science

View full text Add to dashboard Cite

1. Cumulative inbreeding attributable to selection in a finite population after long-term reciprocal recurrent selection (RRS) and modified RRS (MRRS) was studied in two White Leghorn lines. 2. Pedigree information was analysed for a period of 24 generations. In one generation, progeny of full-sib, half-sib and unrelated pureline as well as reciprocal cross-line matings were produced. 3. The structure of the two pure lines, which have been consistently used as part of the commercial cross, was documented in terms of numbers of sires and dams mated to produce sons and daughters, and variance of family size. On average, 87 sires and 870 dams per generation were mated to produce offspring. 4. Cumulative inbreeding values determined from pedigree data were compared with estimates from effective population size and variation of family size. 5. The increase in average inbreeding over 23 generations was 11.9% for line A and 10.8% for line B or 0.49% per generation, based on pedigree data. 6. Estimates from family structure were slightly higher: 12.6% for line A and 12.0% for line B or 0.54% per generation. 7. The increase in inbreeding appeared to be linear and independent of the selection method (MRRS compared to RRS).

show abstract

Battery Cages and the Deep Litter System for the Management of Domestic Laying Fowls: the Problem of Inconsistent Results

Mrode

Akinokun

1985

World's Poultry Science Journal

View full text Add to dashboard Cite

Genotype by type of housing interaction in populations of white Leghorns under reciprocal recurrent selection

Cited by 4 publications

References 11 publications

Effectiveness of Progeny Test Index Selection for Field Performance of Strain-Cross Layers

Effectiveness of Progeny Test Index Selection for Field Performance of Strain-Cross Layers

Cumulative inbreeding in commercial White Leghorn lines under long‐term reciprocal recurrent selection

Battery Cages and the Deep Litter System for the Management of Domestic Laying Fowls: the Problem of Inconsistent Results

Contact Info

Product

Resources

About