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No description available.

No description available.

No description available.

No description available.

No description available.

Tobacco mosaic virus (TMV) is an extensively studied RNA virus that reduces quality and yield in commercially grown tobacco (Nicotiana tabacum L.). The virus is transmitted mechanically, although infections have been associated with contaminated seeds with the seed coat being the source of virus. Thus, TMV transmission is said to be seedborne (as opposed to true seed transmission where the embryo is infected). The objective of this study was to identify TMV concentrations in the three components of an individual tobacco seed: seed coat (SC), endosperm (ED), and embryo (EM). Six hundred seed from TMV infected K 326 flue-cured cultivar tobacco plants were carefully dissected into the three components. Total RNA was extracted from each sample and synthesized into cDNA for analysis. A quantitative real-time PCR (RT-qPCR) assay was developed to quantify viral titers in each component, while endpoint PCR confirmed RT- qPCR results and established a threshold viral cycle (Ct) value. Endpoint PCR results revealed viral accumulation in all three components of a tobacco seed. The highest concentration of TMV was in the SC, followed by ED and EM. A similar viral concentration gradient was observed in each individual tobacco seed from all three experimental plants. This is the first detection of TMV in tobacco embryos and suggests the virus can be seed transmitted. / Master of Science / Tobacco mosaic virus (TMV) is a widely studied plant virus that affects tobacco, tomato, pepper, and many other crops throughout the world. The virus is easily transmitted through contaminated tools or machinery, workers’ hands or clothing, or when an infected leaf comes into contact with an uninfected leaf. For years, TMV transmission was said to be seedborne, not seed transmitted, meaning that seedling infection comes from the infected external seed coat of the seed. Seed transmission of the virus has yet to be proven because of the difficulty to fully separate tobacco seed tissues. The objective of this study was to identify TMV concentrations in the three components of an individual tobacco seed: seed coat (SC), endosperm (ED), and embryo (EM). Six hundred seed from TMV infected tobacco plants were carefully dissected into the three components. Total RNA was extracted from each sample, and synthesized into cDNA for analysis. A quantitative real-time polymerase chain reaction (RT-qPCR) assay was developed to quantify viral concentrations in each component. Endpoint PCR was used to confirm the quantitative results of RT-qPCR. Results revealed TMV accumulation in all three components of a tobacco seed, the highest concentration detected in the SC, followed by ED and EM; this pattern was observed from each plant. This is the first report of TMV being detected in embryos of tobacco seed which suggests that TMV can be seed transmitted.

M.S.

The objectives of the study were to develop a discrete dynamic model to explain the duality of supply flows from production and inventory-stocks, to specify a monthly sectoral model of the United States vegetable oilseeds, oils, and oil products industry, to analyze policy alternatives using simulation, and to evaluate the potential of optimal control theory for stabilizing prices in the industry. A theoretical model of consumer and producer behavior was developed which, following optimization and aggregation, yielded a 4 equation simultaneous representation of a general market system. On the basis of the theoretical model an empirical model of the industry was constructed which included 4 sub-models, each simultaneous or block simultaneous in structure. The first sub-model consisted of 14 equations and included the final products of the industry--cooking oil, shortening, ma.rgarine, and peanut butter. The second industry sub-model consisted of 17 equations and included the markets for finished soybean oil, semi-finished soybean oil, soybeans, and soybean meal. The third industry sub-model consisted of 18 equations and included the markets for finished and semi-finished cottonseed oil, peanut oil, and peanuts. The fourth sub-model consisted of 10 equations and included the markets for palm and coconut oil. Each sub-model was estimated using OLS or 3SLS. The data base consisted of 136 observations covering the period January 1965 to April 1976. / Ph. D.

Soybean (Glycine max (L.) Merr) cultivars with genetic reduction in seed phytate concentration will be a valuable resource to livestock producers both nutritionally and economically, as well as in the preservation of the environment. However, due to association with reduced seed germination and field emergence potential, low phytate (LP) soybean cultivars are not being advanced to commercialization. Soybean breeders of LP lines must adjust their techniques and resources in order to efficiently select LP germplasm. Reduced seed germination and field emergence potential associated with LP germplasm eliminates many individuals with the desired LP trait during early generation population development, making improvement of agronomic performance among LP lines difficult. Thus, development of resources for improved phenotyping, genotyping, and early generation population development will facilitate the commercialization of LP cultivars. Discovery of variation for field emergence potential among F2-derived LP families suggests the potential for using a pedigree method for early generation population development in LP germplasm, as it preserves diversity and allows selection for improved field emergence. Integration of markers into a pedigree method will be useful to breeder. An example is BARCSOYSSR_11_1495 with 90-93% selection efficiency in various V99-5089-derived populations. Another resource for improved LP selection is a time-efficient, high-throughput modified iron (Fe) colorimetric phytate assay that does not suffer from inorganic phosphorus (P) concentration interference. Together these tools will provide breeders more accurate selection of LP lines. / Master of Science