Degree Type

Dissertation

Date of Award

1998

Degree Name

Doctor of Philosophy

Department

Agronomy

First Advisor

Kendall R. Lamkey

Abstract

Recurrent selection methods have been utilized by maize breeders for population improvement. There have been numerous methods described and comparisons of such methods are needed to determine the most efficient methods for maize improvement. The objectives of this experiment were to: compare seven recurrent selection methods for response in the same base population, compare responses to selection with varying effective population sizes, and to estimate the effects of genetic drift in these selection programs;The results from our studies indicate that inbred progeny methods resulted in the greatest responses to selection for all traits. This was in agreement with theory but not with several previous studies of this nature. Effective population size comparisons showed that intermating less than ten individuals resulted in significant inbreeding depression in the populations per se. Intermating 10--30 individuals resulted in the same responses to selection. The effects of genetic drift were apparent in the responses for all selection methods. In general, the estimates of genetic drift were opposite in sign to that of the direction of selection.

DOI

https://doi.org/10.31274/rtd-180813-13805

Publisher

Digital Repository @ Iowa State University, http://lib.dr.iastate.edu/

Copyright Owner

Roger Alan Weyhrich

Language

en

Proquest ID

AAI9911655

File Format

application/pdf

File Size

136 pages

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