University of Illinois Urbana-Champaign

Response to Selection for Pupal Weight With and Without Assortative Mating in Tribolium Castaneum

Mwenya, Wilson Nelson Mulenga

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Description

Title
Response to Selection for Pupal Weight With and Without Assortative Mating in Tribolium Castaneum
Author(s)
Mwenya, Wilson Nelson Mulenga
Issue Date
1984
Department of Study
Animal Sciences
Discipline
Animal Sciences
Degree Granting Institution
University of Illinois at Urbana-Champaign
Degree Name
Ph.D.
Degree Level
Dissertation
Keyword(s)
Biology, Genetics
Abstract
  • Joint effects of pre-selection mating system (random: R; assortative: A), selection mating system (R;A) and percent truncation selected (20%; 50%; 0% (control)) were studied in a 2 x 2 x 3 factorial experiment with 5 replicates to examine direct response to selection for pupal weight (PW), and correlated responses for larval weight (LW) and pupation time (PT) in Tribolium castaneum. Prior to selection two groups, each with 50 males mated to 100 females were either R-mated or A-mated for 3 generations. At generation 3, 6 lines were formed in each group, one for each selection mating system-selection intensity combination, and selection began. Each line was maintained during 2 generations of selection by 10 pair-matings.
  • Half-sib (R-mated group) and minimum chi-square estimates of heritability (A-mated group) were, respectively, for PW: .26 (+OR-) .12 and .39 (+OR-) .02; LW: .36 (+OR-) .13 and .49 (+OR-) .04; and PT: .29 (+OR-) .08 and .25 (+OR-) .03.
  • Estimates of realized heritability of PW, calculated as the ratio of total response (deviated from the control lines) to cumulative selection differential, were: (UNFORMATTED TABLE FOLLOWS)
  • Pre-selection x selection mating system
  • Percentage
  • Selected RR RA AR AA
  • 20% .30 (+OR-) .04 .31 (+OR-) .11 .29 (+OR-) .07 .39 (+OR-) .04
  • 50% .12 (+OR-) .04 .19 (+OR-) .16 .23 (+OR-) .08 .30 (+OR-) .05(TABLE ENDS)
  • Realized heritability of PW was increased by pre-selection assortative mating (P < 0.10), and by more intense selection (P < 0.05); the mating system during selection did not affect realized heritability. There were no clear correlated responses to selection for PW.
  • The experiment indicated the following: (1) assortative mating of parents for a few generations prior to selection enhanced direct short-term response to selection compared to random mating of parents; (2) assortative mating during selection did not significantly increase realized heritability, irrespective of selection intensity; (3) pre-selection assortative mating would not enhance short-term response per unit time (generation) of preselection and selection compared to selection from the onset; and (4) applying low selection intensity for the purpose of not constraining the effectiveness of assortative mating was not useful. The effects of assortative mating on long-term direct and correlated responses to selection need to be investigated.
Graduation Semester
1984
Type of Resource
text
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http://hdl.handle.net/2142/70011

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