Anther-derived monoploids of Solanum phureja were utilized to investigate factors essential to an efficient method of regenerating doubled monoploids (DMs). The presence of silver thiosulfate (STS) in the MS basal medium did not affect the frequency of cells with 2x nuclei but increased the proportion of cells with 1x nuclei and decreased the proportion with 4x nuclei. Results indicated that STS lower the occurrence of endopolyploid nuclei. The production of DMs was not affected by the presence of STS in MS basal medium on which the source of leaf explants was maintained. The incubation of leaf cultures in the dark or light during the callus induction phase did not influence the subsequent regenerative ability of the monoploids. However, there was a significant genotype by incubation condition interaction. Overnight incubation on MS medium with benzyladenine (BA) pulse prior to transfer to regeneration medium did not affect regeneration.
Field evaluation showed various responses of DMs in terms of growth and yield compared to their anther donors or corresponding F₁ progeny. Female fertility was observed in a majority of the DMs verifying their applicability as parental genotypes in practical breeding.
Efforts to generate potato hybrids based on selection of genetically diverse parents using RAPD markers and to develop high yielding diploid potato germplasm that may be instrumental in new cultivar development were addressed. Genetic diversity among in vitro plantlets of S. phureja monoploids (which represent DM maternal genotypes) and diploid heterozygous pollinators (ID lines) was estimated using RAPD markers. Field evaluation revealed significant differences among fourteen F₁ hybrids of S. phureja DM x ID with respect to total tuber number, total tuber yield, average tuber weight and vigor. Using simple matching or Jaccard coefficients, the largest parental genetic distance was associated with the highest total tuber yield among the progenies of DM parents. Based on our results, RAPDs have the potential to facilitate the identification of diverse parents to maximize the expression of heterosis in S. phureja hybrids.
SSR markers were used to analyze the genetic composition of anther-derived potato plants. Anther-derived monoploids exhibited a single allele as expected. Both homozygous and heterozygous diploids were identified. SSRs were also utilized to study allelic segregation in an F₁ population. Results of this experiment revealed Mendelian inheritance of SSR alleles. / Ph. D.
| Identifer | oai:union.ndltd.org:VTETD/oai:vtechworks.lib.vt.edu:10919/38088 |
| Date | 06 June 2008 |
| Creators | Paz, Margie Margarita |
| Contributors | Genetics, Veilleux, Richard E., Buss, Glenn R., Ha, Sam B., Hilu, Khidir W., Saghai Maroof, Mohammad A. |
| Publisher | Virginia Tech |
| Source Sets | Virginia Tech Theses and Dissertation |
| Language | English |
| Detected Language | English |
| Type | Dissertation, Text |
| Format | x, 126 leaves, BTD, application/pdf, application/pdf |
| Rights | In Copyright, http://rightsstatements.org/vocab/InC/1.0/ |
| Relation | OCLC# 35195924, LD5655.V856_1996.P39.pdf |
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