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ALLOZYME POLYMORPHISMS RELATED TO MATING SYSTEM AND MORPHOLOGICAL TRAITS IN TWO MASS SELECTED CORN POPULATIONS

LINDA MAE POLLAK, University of Nebraska - Lincoln

Abstract

Genotypes at eight or nine enzyme loci were determined using starch gel electrophoresis and histochemical staining in two mass selected corn populations, NHG(M)P17 and NHG(M)C22. Two samples were used from each population. One consisted of 40 main stalk ears each from an individual plant, and the other consisted of 40 tiller ears each from an individual plant not included in the first 40. Estimates of mating system parameters (adult genotypes, pollen pool allelic frequencies and outcrossing rates) were made in each sample. Comparison of genotypic frequencies in the selected populations and the base population showed greater levels of heterozygosity in the selected populations. An increase of heterozygosity was possibly associated with increased grain yield in C22 since more heterozygosity was found in C22 (selected for grain yield) than in P17 (selected for prolificacy). Differences in adult and pollen pool allelic frequencies were found in C22. They were likely due to increased tillering in C22 which caused differential pollen production of individual plants. Single-locus outcrossing estimates fluctuated widely within samples. Multilocus outcrossing estimates were determined to be 1, 0.93, 0.83, and 0.93 in the P17 main stalk ears, P17 tiller ears, C22 main stalk ears, and C22 tiller ears, respectively. Predominant outcrossing but with substantial inbreeding was found in C22, especially on main stalk ears. Virtually no inbreeding was found in P17 main stalk ears. Twenty morphological traits were measured in the field on the sample plants. Stepwise selection of traits, followed by discriminant analysis, was used to determine traits by which genotypes at a particular locus could be differentiated. Homozygotes were discriminated from heterozygotes at the following loci: Got 1, Px 1, Mdh 2, 6-Pgd 1, and (beta) glu 1 in C22, and Got 1, Px 1, and Adh 2 in P17. At AcPh 1 in C22, heterozygotes were discriminated from one homozygote group with a function correlated with yield, and from the other homozygote group with a function correlated with maturity and leaf traits. Traits associated with the discriminant functions exhibited a trend with total yield in C22, and with number of ears or tiller ear yields in P17.

Subject Area

Agronomy

Recommended Citation

POLLAK, LINDA MAE, "ALLOZYME POLYMORPHISMS RELATED TO MATING SYSTEM AND MORPHOLOGICAL TRAITS IN TWO MASS SELECTED CORN POPULATIONS" (1982). ETD collection for University of Nebraska-Lincoln. AAI8306500.
https://digitalcommons.unl.edu/dissertations/AAI8306500

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