Optimum Group Size in Progeny Testing and Family Selection

Alan Robertson

doi:10.2307/2527971

PROGENY GROUP SIZE IN AN ORGANIZED PROGENY TEST PROGRAM OF AI BEEF BULLS USING REFERENCE SIRES

Canadian Journal of Animal Science ◽

10.4141/cjas83-003 ◽

1983 ◽

Vol 63 (1) ◽

pp. 17-26 ◽

Cited By ~ 10

Author(s):

J. L. FOULLEY ◽

L. R. SCHAEFFER ◽

H. SONG ◽

J. W. WILTON

Keyword(s):

Beef Cattle ◽

Key Words ◽

Group Size ◽

Numerical Procedure ◽

Progeny Test ◽

Progeny Testing ◽

Program Optimization ◽

Test Program ◽

Testing Program ◽

Progeny Group

A numerical procedure was utilized to optimize the number of progeny for young bulls and reference sires in a beef sire progeny testing program. Optimization was based on attaining a desired level of accuracy on the types of comparisons that were to be made after the test was completed. As heritability increased, the total number of progeny required decreased, but the percentage of reference sire progeny remained the same. There were near optimum progeny distributions with smaller total number of progeny and only slightly less accurate than the optimum solutions which could also be considered for application. Key words: Progeny testing, beef cattle, optimum designs, reference sires

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Short-term Progeny Tests and Second Generation Breeding in Slash Pine

Canadian Journal of Forest Research ◽

10.1139/x73-024 ◽

1973 ◽

Vol 3 (2) ◽

pp. 165-169

Author(s):

E. C. Franklin ◽

A. E. Squillace

Keyword(s):

First Generation ◽

Second Generation ◽

Slash Pine ◽

Mass Selection ◽

Progeny Testing ◽

Family Selection ◽

Short Term ◽

Major Disadvantage ◽

Selection For ◽

Almost All

Progeny testing is the most widely used method for intensive genetic evaluation of selected forest trees, but its major disadvantage is the length of time needed to get results. To circumvent this problem in selection for a multiproduct strain of slash pine (Pinuselliottii Engelm.), a system for short-term (3-year) progeny testing was developed. Oleoresin yields of selected second-generation 19-year-old parent trees were compared with yields of their 3-year-old offspring. Both parents and offspring showed little variation and a low offspring–parent correlation (r = 0.18), but other traits based on the same parent trees when they were 25 years old and their 3-year-old offspring showed relatively large amounts of variation and moderate to strong offspring-parent correlations: height, r =.56; volume, r = 0.43; turpentine, r = 0.71; ethanol–benzene extractives, r = 0.38; specific gravity, r = 0.43; moisture content, r = 0.34. Thus, indications are that additional gains could be made in the first generation by selecting among parent trees on a progeny performance basis in all traits except oleoresin yield. Original mass selection for oleoresin yield achieved gains of 100% improvement and apparently exploited almost all of the genetic variation in the base population. In second generation selection, progeny testing will be used primarily in screening for fusiform rust resistance. Between-family plus within-family selection will be used for other traits.

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Comparing gain and optimum test size from progeny testing and phenotypic selection in Pinus sylvestris

Canadian Journal of Forest Research ◽

10.1139/x07-005 ◽

2007 ◽

Vol 37 (7) ◽

pp. 1227-1235 ◽

Cited By ~ 8

Author(s):

Björn Hannrup ◽

Gunnar Jansson ◽

Öje Danell

Keyword(s):

Pinus Sylvestris ◽

Genetic Parameters ◽

Phenotypic Selection ◽

Tree Breeding ◽

Optimum Number ◽

Progeny Testing ◽

Southern Sweden ◽

Family Selection ◽

Investment Level ◽

Optimum Balance

The profit from tree breeding is dependent on the amount of money invested and how these resources are spent, particularly in the testing of selection candidates. Simulations of within-family selection were used to find the optimum balance among the number of candidates, progenies per candidate, and test sites for a given investment level and to compare the profit from progeny testing and phenotypic selection. The simulations were based on genetic parameters estimated from 66 Pinus sylvestris L. progeny trials in southern Sweden and on compilations of breeding costs. For progeny testing the optimum number of candidates and test sites increased with increasing investment level, whereas the number of progenies per candidate and site decreased and stabilized at ca. 10 individuals. The maximum annual profit for the phenotypic selection was higher and occurred at a lower investment level than for progeny testing. Among the two alternatives of progeny testing studied, the intensive alternative with practices to stimulate early flowering showed a higher maximum annual profit than the base alternative.

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