Comparisons of traits of aggressiveness in sexual and asexual populations of Puccinia coronata

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dc.contributor.author Oard, James
dc.contributor.department Plant Pathology and Microbiology
dc.date 2018-08-15T17:02:55.000
dc.date.accessioned 2020-07-02T06:01:50Z
dc.date.available 2020-07-02T06:01:50Z
dc.date.copyright Sat Jan 01 00:00:00 UTC 1983
dc.date.issued 1983
dc.description.abstract <p>It is generally considered advantageous for populations to periodically recombine their genes in order to increase both the genetic variability and the rate of response to changing environments. Theoretical and experimental evidence, however, has not clearly substantiated this view and actually has led to some confusion about the role of gene recombination in the origin and maintenance of traits of aggressiveness in pathogen populations. Therefore, field and growth chamber studies were conducted to compare sexual and asexual populations of Puccinia coronata for traits of aggressiveness. In 1979, aecial cultures of Puccinia coronata were collected from the alternate host, Rhamnus cathartica, in a nursery in Minnesota to obtain a sample population that had undergone sexual reproduction. A second population distant from R. cathartica consisted of asexual uredial cultures from southern Texas. Isolates obtained from these cultures were used individually to inoculate susceptible oat (Avena sativa) cultivars in both studies. The growth chamber study indicated that the sexual population exhibited significantly higher levels of aggressiveness than the asexual population for several traits, including spore production and latent period;Gene recombination provided no consistent advantage, however, to the sexual population in the field study. This may be due to the absence of the effects of genetic drift in the two large pathogen populations. The general response to selection for increased levels of aggressiveness in the asexual population was small compared to that of the sexual population on the cultivars Lang and Otee which suggests that the advantage of gene recombination will vary over changing host populations and fluctuating environments.</p>
dc.format.mimetype application/pdf
dc.identifier archive/lib.dr.iastate.edu/rtd/7644/
dc.identifier.articleid 8643
dc.identifier.contextkey 6323500
dc.identifier.doi https://doi.org/10.31274/rtd-180813-5415
dc.identifier.s3bucket isulib-bepress-aws-west
dc.identifier.submissionpath rtd/7644
dc.identifier.uri https://dr.lib.iastate.edu/handle/20.500.12876/80544
dc.language.iso en
dc.source.bitstream archive/lib.dr.iastate.edu/rtd/7644/r_8316154.pdf|||Sat Jan 15 01:51:39 UTC 2022
dc.subject.disciplines Agriculture
dc.subject.disciplines Plant Pathology
dc.subject.keywords Plant diseases
dc.subject.keywords Plant pathology
dc.subject.keywords seed and weed sciences
dc.title Comparisons of traits of aggressiveness in sexual and asexual populations of Puccinia coronata
dc.type article
dc.type.genre dissertation
dspace.entity.type Publication
relation.isOrgUnitOfPublication a26b5928-54bb-4a0b-a973-95d649d1ad83
thesis.degree.level dissertation
thesis.degree.name Doctor of Philosophy
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