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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Derivation and Comparison of Androgenic and Gynogenic Monoploid Potato Families

Cutright, Rebecca J. 09 September 1998 (has links)
Monopoloid potato (2n = 1x = 12) can be derived either paternally through anther/microspore culture or maternally through crossing with a haploid-inducing pollinator. Evidence from other genera suggests that androgenic and gynogenic haploid populations derived from the same parent may differ due to gametic selection and/or epigenetic factors. Our objectives were to derive androgenic and gynogenic monoploid populations from each of two diploid (2n = 2x = 24) Solanum phureja clones and compare their phenotypic characteristics in a greenhouse study. A haploid-inducing pollinator, S. phureja IVP101, was crossed to two selections of S. phureja (PP5 and BARD1-3). A total of 185 fruit was obtained from PP5 and 398 from BARD1-3, resulting from 85% and 65% fruit set, respectively. Seed lacking the dominant embryo spot marker carried by IVP101 were selected and germinated in vitro. From 29,300 PP5 x IVP101 seeds, 278 were spotless, resulting in 27 monoploids. Approximately 37 monoploids were obtained from the 99,500 BARD1-3 x IVP101 seeds of which 500 were spotless. In anther culture, PP5 and BARD1-3 yielded 0.16 and 1.67 embryos per anther respectively of which 51% and 44% of the regenerants were monoploid. A total of 32 anther-derived monoploids has been obtained from PP5 and 130 from BARD1-3. Rooted cuttings of 21 androgenic and 21 gynogenic PP5 monoploids were established in a greenhouse in each of three randomized complete blocks. Although the anther-derived monoploids appeared more vigorous, none of the differences between the two populations were significant. Flow cytometry revealed that anther derived progeny of PP5 and BARD1-3 had 3-8% greater nuclear DNA content than gynogenic monoploids derived from the same parental clones. / Master of Science
2

The Potential for Green Fluorescent Protein as a Screening Tool in the Production of Haploid Potato Plants

Palumbo, Rose 31 December 2003 (has links)
A hybrid between a highly regenerative diploid clone (BARD 1-3) of Solanum phureja and haploid inducer IVP 101 was transformed with Agrobacterium tumefaciens strain 4404 containing plasmid pHB2892 with genes for green florescent protein (GFP) and kanamycin resistance. Hemizygous primary transformants (To) were produced from three leaf discs: 17 diploid plants from one leaf disc, three and nine tetraploids from the other two leaf discs. GFP expression was observed qualitatively under fluorescence microscopes and quantitatively with a GFP meter. Anther culture of tetraploids produced 29 plants, none with high levels of GFP. Segregation ratios for tetraploid T1 seedlings fit models for single duplex insertions (35 transgenic: 1 non) or double simplex insertions (15 transgenic: 1 non). Diploid T1 seedlings segregated for deleterious traits: dwarfed size and curled leaves, as well as the GFP transgene. Similar segregation patterns in diploid families implied that all diploids may have been from the same transformation event. The cumulative segregation showed the dwarfed and curled plants fit a single recessive gene ratio (3 normal: 1 mutant), and GFP fit a double-copy insertion ratio (15 transgenic: 1 non). There was substantial GFP silencing evidenced by the loss of expression in plants that had originally been selected for high GFP. However, six selections were found to be free of deleterious traits, consistently high expressers of GFP, and producers of stainable pollen with less 2n than IVP 101. / Master of Science

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