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Thesis (M.S.)--University of Nebraska--Lincoln, 1966. Department of Agronomy.


Copyright 1966, the author. Used by permission.


Genetic variation in populations used by plant breeders is essential if improvement is to be made by any selection procedure. Since variability can be induced by mutagenic agents, investigations were introduced in 1953 at the University of Nebraska to study the effect of radiation on genetic variation in quantitative traits in maize (Zea mays). A large number of sub-lines were developed from long-time inbred lines by use of ionizing and non-ionizing radiations. Some of these sub-lines were observed to be distinctly different from the parent lines from which they were developed.

This study involves three of those mutant genotypes which resulted from the irradiation of two inbred lines. Although it is not expected that any of these mutants may be useful as lines in a maize breeding program, the methods used and the conclusions drawn from this investigation may be extended to further irradiation studies in which improved phenotypes and genotypes may be desired. The goal of this study is to determine whether the observed phenotypic changes resulted from genetic changes, and if so, to determine the genetic mechanisms involved, including the number of loci affected, degree of dominance, and existence of epistasis. Restrictions include a limited seed supply and data obtained from only one growing season.

Advisor: Charles O. Gardner.