Genetic Recombination in Maize as Affected by Ethylenediaminetetraacetic Acid and Dimethyl Sulfoxide1
- Charles A. Ihrke and
- W. E. Kronstad2
Recombination frequencies for seven selected regions on five chromosomes of maize (Zea mays L.) were measured to ascertain the effect of complexing agents on recombination. Ethylenediaminetetraacetic acid (EDTA) and dimethyl sulfoxide (DMSO) were used in three concentrations singly, and in all combinations. Plants heterozgous for linked genes governing endosperm and seedling characteristics were treated with premeiotic foliar spray of EDTA and DMSO for two durations. Appropriate crosses were made and recombination values were calculated from data resulting from test cross and sib cross progeny.
The complexing agents were found to influence the frequency of recombination in each of the regions tested. Increases in recombination frequencies were significant in six of the seven chromosome's regions when treated with several concentrations of the two complexing agents. Reduction in recombination was observed in two regions treated at high concentrations of the chemicals and at the longer duration. In these latter cases, it was concluded that a threshold had been reached causing interference with crossing over or with recovery of recombination products.
Changes in recombination frequency were found to be of similar magnitude whether the complexing agents were used alone or in combination, and it was concluded that the two chemicals did not have a synergistic effect in changing recombination frequency. Although the two agents differ in cation affinity both were shown to influence crossing over, indicating that the action was by a mechanism other than removal of a specific cation from the chromosome. A relationship was shown between length of crossover region and effect of the chemical treatment. No such relationship was found between specific locations in chromosomes and response to complexing agents for the seven regions tested.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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