Quantitative inheritance studies in sugar-cane. II. Correlations and predicted responses to selection

1971 ◽  
Vol 22 (1) ◽  
pp. 103 ◽  
Author(s):  
DM Hogarth
Keyword(s):  
Sugar Cane ◽  
Standard Errors ◽  
Mass Selection ◽  
Quantitative Inheritance ◽  
Selection System ◽  
Family Selection ◽  
Genotypic And Phenotypic Correlations ◽  
Selection For ◽  
Genotypic Correlations ◽  
Brix Value

Predicted responses to selection for a number of characters, and genotypic and phenotypic correlations between characters were studied in sugar-cane seedling populations. Predicted response from family selection was found to be much greater than from mass selection for all characters except Brix value. A selection system incorporating family selection for grade (phenotypic score) and mass selection for Brix value was proposed for further investigation. Many genotypic correlations between important characters were positive and quite high with the notable exception of the correlation between stalks per stool and weight per stalk, which was high and negative. Genotypic correlations between arrowing percentage (an undesirable character) and all other characters except stalks per stool were high and negative, but most had large standard errors.

scholarly journals Two-way within-family and mass selection for 8-week body weight in different mouse populations

1984 ◽  
Vol 43 (2) ◽  
pp. 191-200 ◽  
Author(s):  
Ines von Butler ◽  
Henning Willeke ◽  
Franz Pirchner
Keyword(s):  
Body Weight ◽  
Inbred Strains ◽  
Selection Response ◽  
Mass Selection ◽  
Individual Selection ◽  
Family Selection ◽  
Body Weights ◽  
Selection For ◽  
Size At Birth ◽  
Better Than

SUMMARYTwo mouse populations, randombred albino mice and a cross of four inbred strains, were divergently selected for high (H8) and low (L8) 8-week body weight over 18 generations using within-family and individual selection. The crossbreds showed asymmetry of selection response and realized heritabilities (H8 0·29 ± 0·01; L8 0·17 ± 0·01). In the randombred population realized heritabilities were symmetrical (H8 0·23 ± 0·01; L8 0·22 ± 0·02). Over the first nine generations individual selection was nearly 40 per cent better than within-family selection, as was expected from the full sib correlation in both populations. As selection progressed, within-family selection reached 82% and 61% of the responses obtained with individual selection in the crossbreds and randombred respectively. Correlated responses for 3-week (weaning) and 5-week body weights agreed with observations made on direct responses, but selection for L8 did not reduce weaning weight. Selection for L8 decreased and selection for H8 increased first litter size at birth. However, mass-selected L8-pairs had a higher life-reproduction and life-span than H8-pairs.

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

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.

EARLY GENERATION SELECTION FOR PROTEIN IN Glycine max × G. soja CROSSES

1981 ◽  
Vol 61 (4) ◽  
pp. 901-908 ◽  
Author(s):  
L. R. ERICKSON ◽  
W. D. BEVERSDORF ◽  
H. D. VOLDENG
Keyword(s):  
Protein Content ◽  
Seed Protein ◽  
Glycine Soja ◽  
Mass Selection ◽  
Seed Protein Content ◽  
Family Selection ◽  
Early Generation ◽  
Early Generation Selection ◽  
The Mean ◽  
Selection For

Early generation selection for high seed-protein content would be desirable in breeding programs attempting to combine high yield and high protein content in soybeans (Gycine max (L.) Merr.). The heritability of seed-protein content in the F2 and F3 was measured in four crosses and mass and family selection for protein were compared in the F3 of these crosses. Glycine soja Sieb. and Zucc., a putative wild ancestor of the soybean, was the male parent in all crosses and selection intensity was at 10%. The heritability of protein in the F2, calculated by parent-offspring regression, was 27%. The broad-sense heritability of protein in F3 families grown over two locations in one season was 78%. Mean protein content for every selected population was greater (P ≤ 0.01) than the mean for the non-selected control population (45.3%). Mean protein contents of the F4 populations resulting from these selection methods were: mass selection in the F2 and F3, 48.0%; mass selection in the F3 following one generation of single seed descent, 48.8%; selection among F3 families, 47.6%; selection among and within F3 families, 47.5%. Either method of mass selection was superior to either method of family selection at the 0.01 level. Although early selection (mass or family) raised the mean protein content of a population, segregation continued to give rise to low-protein genotypes thereby requiring further selection.

Divergent Mass Selection for Carotenoids in a Flue‐Cured Tobacco Populations 1

Crop Science ◽  
1984 ◽  
Vol 24 (1) ◽  
pp. 67-71 ◽  
Author(s):  
R. A. Beatson ◽  
E. A. Wernsman ◽  
R. C. Long
Keyword(s):  
Mass Selection ◽  
Selection For

Mass Selection for Tobacco Seedling Weight under Two Nutrient Regimes 1

Crop Science ◽  
1983 ◽  
Vol 23 (6) ◽  
pp. 1163-1167 ◽  
Author(s):  
D. A. Van Sanford ◽  
D. F. Matzinger
Keyword(s):  
Mass Selection ◽  
Selection For

scholarly journals EFFECTS OF POPULATION SIZE AND SELECTION INTENSITY ON SHORT-TERM RESPONSE TO SELECTION FOR POSTWEANING GAIN IN MICE

Genetics ◽  
1973 ◽  
Vol 73 (3) ◽  
pp. 513-530
Author(s):  
J P Hanrahan ◽  
E J Eisen ◽  
J E Legates
Keyword(s):  
Population Size ◽  
Selection Response ◽  
Selection Intensity ◽  
Realized Heritability ◽  
Family Selection ◽  
Effective Population ◽  
Population Sizes ◽  
Selection For ◽  
Selection Intensities ◽  
Term Response

ABSTRACT The effects of population size and selection intensity on the mean response was examined after 14 generations of within full-sib family selection for postweaning gain in mice. Population sizes of 1, 2, 4, 8 and 16 pair matings were each evaluated at selection intensities of 100% (control), 50% and 25% in a replicated experiment. Selection response per generation increased as selection intensity increased. Selection response and realized heritability tended to increase with increasing population size. Replicate variability in realized heritability was large at population sizes of 1, 2 and 4 pairs. Genetic drift was implicated as the primary factor causing the reduced response and lowered repeatability at the smaller population sizes. Lines with intended effective population sizes of 62 yielded larger selection responses per unit selection differential than lines with effective population sizes of 30 or less.

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