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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.

Natural variation in the relative proportions of saturated and unsaturated fatty acids in seed oils of plants is enormous when considered across a broad taxonomic range of oil seeds. It has been shown that this variation follows a latitudinal cline where the proportions of unsaturated fatty acids increases with increasing latitude as the unsaturated fatty acids in seeds provide energy at a faster rate to germinating seeds at higher latitudes. This variation which follows a latitudinal cline suggests that there may be an adaptive role for this variation. We tested this hypothesis in Arabidopsis thaliana which followed the same trend seen in Helianthus and other angiosperms. In order to understand the underlying genetics of the regulation of the relative proportions of fatty acids and their role in plant evolution, we mapped quantitative trait loci (QTLs) and candidate genes. Here we identified 67 major QTLs responsible for fatty acid synthesis in A. thaliana in Ler-0 x Sha, Ler-0 x Col-4, Ler-2 x Cvi and Ler-0 x No-0 RIL populations. Eight candidate genes were identified based on what is known about seed oil biosynthesis in A. thaliana. Six of the candidate genes collocated to most of the major QTLs. In order to demonstrate that a particular allelic variant is indeed causally related to the phenotype, we investigated DNA polymorphisms in the parental and the RIL line alleles of the collocating candidate genes. Single nucleotide polymorphisms (SNPs) were identified in the collocating candidate genes to study the correlation between the sequence variants and the particular phenotype. We identified 232 SNPs with 77 in the putative regulatory regions upstream of the 5’UTR, 61 in the introns, 18 in the 5’UTR regions, 2 in the 3’UTR regions, and 45 occurring in the exons with 10 non-synonymous substitutions affecting the amino acid residues. We also detected 44 insertions/deletions in the coding, non-coding, 5’UTR, 3’UTR and the regulatory regions. Sequence variation in the fatty acid genes due to SNPs and insertions/deletions should be valuable in tests of association to investigate how the relative proportions of saturated and unsaturated fatty acids are regulated in wild plants and what role they have played in plant evolution and also in breeding oil seed crops that are healthier or have two types of fatty acids in proportions appropriate for different uses. / text