Thesis (M. Ag. Sc.)--University of Adelaide, Dept. of Horticulture, Viticulture and Oenology, 1997. / Includes bibliographical references (leaves 98-123).

Thesis (Ph. D.)--University of Queensland, 2002. / Includes bibliographical references.

Thesis (Ph. D.)--Oregon State University, 2008. / Printout. Includes bibliographical references (leaves 100-108). Also available on the World Wide Web.

Graduation date: 1952

Thesis (Ph. D.)--University of Texas at Austin, 2006. / Vita. Includes bibliographical references.

The cultivated sunflower (Helianthus annuus L., x=17) is one of the most important annual oilseed crops in the world. There are very few publicly shared sequence-based DNA markers and genetic maps in sunflower, even though molecular DNA markers and genetic maps have become widely used in all areas of genetic research and breeding in plant species. The objectives of this study were to develop sequence-based molecular markers and utilize the markers for genetic analyses and constructing maps in the cultivated sunflower. A total of 131 functional simple sequence repeat (SSR) markers were developed for 16 elite inbred lines using a small insert genomic library enriched for short simple sequence repeats. The polymorphism information content (PIC) estimated from 74 polymorphic SSR markers ranged from 0.0 to 0.93 with mean value of 0.55. Tetranucleotide repeats were significantly more polymorphic than dinucleotide and trinucleotide repeats, and no obvious correlation was found between repeat numbers and PIC scores. Genetic distance among 16 inbred lines, estimated from 74 polymorphic SSR markers ranged 0.175 to 0.543. Principal coordinate and cluster analyses of the genetic distance matrix well explained the difference between oilseed lines and confectionery lines, and sterility maintainer lines and fertility restorer lines. A total of 1,090 SSR markers were screened for polymorphism between the parents of two mapping populations. The two genetic maps were constructed by genotyping 94 recombinant inbred lines from a cross between PHA and PHB (276 SSR loci covering 1377.4 cM with mean distance of 4.99 cM), and 94 F��� progeny from a cross between HA370 and HA372 (122 SSR loci integrated into the existing RFLP framework map covering 1348.0 cM with mean distance of 6.77 cM). Ninety-three percent of the SSR markers were mapped to single loci and 56.5% of the loci were co-dominant. Clustering of SSR loci was observed near centromeric regions and most of the distorted loci were mapped to centromeric or distal regions. A concerted effort to develop SSR markers and generate highresolution SSR maps will enhance future fingerprinting analyses, fine-scale genome analyses and molecular breeding in the cultivated sunflower. / Graduation date: 2002

Genotype by environment interaction (GxE) is the tendency of the phenotypic performance of two or more plant genotypes in one environment to not be predictive of their relative performance in another environment. To discover the importance of GxE in this region, a large set of USDA and commercial hybrids were tested in the regions of practical significance to sunflower production in order to produce recommendations regarding mega-environments for yield and oil. Rank changes for oil content occurred among hybrids and two common factors accounted for 68.6% of the total GxE variation. Breeding programs testing pre-commercial hybrids in multiple environments for oil content could be beneficial. Yield covariates for lodging, bird damage, and disease were significant but occurred in different locations with variable severity each year making it difficult to divide the growing region into mega-environments for yield.

No description available.

Since the early 1920s, when furfural was first produced, several other processing routes have been developed but none have been able to produce yields comparable to those obtained in the standard TAPPI procedure for xylan which almost completely converts xylan to furfural. Karl Zeitsch, a German chemist, believed that the key feature of a process which could achieve high yields was rapid removal of the furfural on formation. Zeitsch suggested using gas phase HCl catalysis to produce gaseous furfural from xylan containing material, the process was titled s-Suprayield. The experimental apparatus heated a water and HCl solution to a superheated vapour phase and then allowed for contact of the vapour and a bed of pentosan-containing material (in this case sunflower husks). The raw material was analysed by the TAPPI procedure for xylose while the product solutions were analysed for HCl, acetic acid and furfural by titration and refractive index. Tests were performed at four acid concentrations of 0.5, 1.1, 2.2, 4.3% wt and three different temperatures viz. 163ºC, 152 ºC and 144 ºC. The best yields of over 80% were achieved when an acid concentration of 4.3% was used. Temperature did not appear to be as significant a factor as acid concentration in affecting the furfural yield. At an acid concentration of 0.5% the yield was low ranging from 33% to 42%. The reactor modelling was used to verify the results. The s-Suprayield process has been demonstrated to be successful at mini-pilot plant scale indicating that a process using gaseous catalysis to produce furfural at moderate temperatures and low acid concentrations can work and that further exploration of this process should be undertaken for potential industrial use. Acid concentration was observed to have a significant effect on the reaction yield while the effect of temperature was not clear from the experimental results. Further work should focus on understanding the reaction kinetic and the development of a laboratory scale test method for which parameters such as gas flow rate and temperature can be properly controlled. Product analysis should be more rigorous with the use of an HPLC. / Thesis (M.Sc.Eng.)-University of KwaZulu-Natal, Durban, 2010.

Graduation date: 2005