Performance of Rhode Island Reds and Light Sussex as Compared with That of Their F1 and Three-Way Crossbreds

Knox, C. W.; Gordon, Corinne C.; Mehrhof, N. R.

doi:10.3382/ps.0280415

Cited by 8 publications

(3 citation statements)

References 5 publications

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“…The few experiments reported that are in any way comparable with the present survey do not suggest that our results are atypical. Warren (1942), Knox et at. (1949) and King & Bruckner (1952) did not get as much hybrid gain with breed crosses though the last-mentioned authors used larger numbers.…”

Section: Discussionmentioning

confidence: 99%

Survey of line crosses in a Brown Leghorn flock 1. Egg Production

Blyth

Sang

1960

Genet. Res.

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Six isolate lines of long standing, from the Centre's Brown Leghorn flock, were intermated in all possible directions, providing thirty cross and six pure line samples. Half the birds from each line and reciprocal cross were kept in floor pens and the rest caged in an adjacent battery house.Sexual maturity, survivors' production to 500 days of age, and November through June egg numbers, all showed two main factors contributing to variations in cross performance: (1) a significant association with parental production levels as measured by mid-parent averages, and (2) an additional hybrid gain. For November to June production in pens, this hybrid gain appeared to approach a constant for the cross groups. Additional sources of variation were present in age at sexual maturity.The 500-day records for the penned hybrids exceeded the line average by 50 eggs. Caged samples did less well and showed an advantage of only 34 eggs. In this location the hybrid gain for individual groups decreased with increases in mid-parent level.Egg weight varied negatively with egg numbers only in the upper half of the wide egg-size range. The best layers fell at the lower end of the covariant range for egg size.The importance of improving closed strains may not have been lessened by the expansion of the hybrid side of the poultry industry, for the pattern of relationships of line and cross production in this flock is consistent enough to justify the inference that the best hybrids come from the best-producing parents.

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Section: Discussionmentioning

confidence: 99%

Survey of line crosses in a Brown Leghorn flock 1. Egg Production

Blyth

Sang

1960

Genet. Res.

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“…In four-years' trials in Florida, Knox et al (1949) found the average production to be for Rhode Island Reds: 173, for Light Sussex: 154 and for hybrids between them: 193. Here the increase was about 30 eggs over the mid-point between the parent breeds, a figure with which the increase for the C X K inter-strain hybrids in a shorter laying period compares favorably.…”

Section: -Average Productivity and Size In Purebred And Hybrid Daughtmentioning

confidence: 99%

Heterosis in an Inter-Strain Cross of White Leghorns

Hutt

Cole

1952

Poultry Science

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“…The latter report was based on an extensive Burvey, involving 14,000 birds and 22 different breed crosses. Knox and Olson (1938) found better viability to one year of a{j,e in crosses of Leghorns and Rhode Island Red?, than in the parent stocks. Knox, Qiiinn, and Godfrey (1943) Jull (19oo), using full-sib and half-aib Leghorn makings for three ij;enerationo, found that chick mortality to four weeks was not affected.…”

Section: Selection For T-ceneral Viabilitymentioning

confidence: 99%