Degree Type

Dissertation

Date of Award

2003

Degree Name

Doctor of Philosophy

Department

Agronomy

First Advisor

Michael Lee

Abstract

Plant genomes have the capacity to change in response to abiotic stress and other environmental signals. In maize (Zea mays L.), enhanced genetic recombination in response to low temperature has been shown to alter recombination frequencies in maize (Shams-UI-Islam, 1956). The effect of other environmental stresses on genetic recombination has not been reported in maize. Therefore, the primary objective of this dissertation was to identify whether water-deficit stress during meiosis and defoliation during pre-meiosis will affect meiotic recombination in maize. A secondary objective was to observe crossover occurrence and distribution. Three experiments are presented in this dissertation. The first two experiments focus on the effect of water stress on meiotic recombination of two maize genotypes (B73/Mo17 and Mo17/H99). The third experiment investigates the effect of defoliation on meiotic recombination of Mo17/H99. For each experiment male meiotic recombination was observed in backcross populations derived from 3 stress and 3 non-stress plants. Progeny of each population was genotyped at microsatellite loci to create genetic maps for chromosomes 1 and 10. Comparisons of recombination were made within and between treatments. For water-deficit experiments genetic maps of chromosomes 1 and 10 were larger for stressed plants. Results suggest that increase on recombination under water-deficit stress is a general response in maize. Maps of populations subjected to defoliation did not differ in length from those of the control treatment.

DOI

https://doi.org/10.31274/rtd-180813-135

Publisher

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

Copyright Owner

Luis A. Verde

Language

en

Proquest ID

AAI3085950

File Format

application/pdf

File Size

165 pages

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