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GENETIC MODELS FOR INTERPOPULATION CROSSES (ADAPTED X EXOTIC) (QUANTITATIVE, SELECTION, COMPUTER SIMULATION)
Abstract
Theoretical quantitative and population genetics were used to investigate the introgression of exotic germplasm into adapted breeding populations for improvement of a quantitative trait. The specific objective was to determine the best foundation population (F(,2) or first backcross to the adapted) to use for achieving short-term and long-term goals from selection. Two genetic models were used to simulate selection in an F(,2) and a backcross population and to compare the means of the two populations in each cycle of selection. Theoretical distributions of genotypes were used in the first model. Genetic variance components and prediction equations were used in the second model. Several factors which could affect the comparison of simulated selection response in the F(,2) or a backcross were included in the models. The factors were (1) number of loci in the adapted and exotic populations with favorable alleles present, (2) effect of each locus on the expression of the quantitative trait, (3) state of the original adapted and exotic populations (homozygous or heterozygous), (4) linkage among loci affecting the quantitative trait, (5) epistasis among loci affecting the quantitative trait, and (6) population size used during selection. Results of simulated response to selection indicate (1) the F(,2) is better for both long-term and short-term goals when the adapted and exotic populations perform the same, (2) the backcross to the adapted population is better for short-term goals when the adapted population is superior, (3) the backcross to the adapted population is better for long-term goals when the adapted population is superior due to a greater number of loci with favorable alleles present, and (4) the F(,2) is better for long-term goals when the adapted population is superior due to presence of favorable alleles at loci with a large effect.
Subject Area
Agronomy
Recommended Citation
BRIDGES, WILLIAM CARROLL, "GENETIC MODELS FOR INTERPOPULATION CROSSES (ADAPTED X EXOTIC) (QUANTITATIVE, SELECTION, COMPUTER SIMULATION)" (1984). ETD collection for University of Nebraska-Lincoln. AAI8509857.
https://digitalcommons.unl.edu/dissertations/AAI8509857