Thesis (Ph.D.)--University of Adelaide, Dept. of Agronomy, 1980.

Thesis (Ph. D.)--Oklahoma State University, 2005. / Vita. Includes bibliographical references (p.48-52).

Soybean [Glycine max (L.) Merrill] is an important source of protein and oil for both nutritional and industrial applications. Increasing seed yield and protein concentration is the main goal of many soybean breeders to meet market demands. Soybean breeders have occasionally succeeded in producing high yielding cultivars with increased protein content using conventional means despite the negative correlation that exists between these two traits. The efficiency of breeding for seed yield and protein concentration improvement in soybean could be increased using marker assisted selection (MAS) breeding strategies to select genotypes containing favorable alleles for faster cultivar development. The objective of this study was to identify quantitative trait loci (QTL) associated with seed yield, and separately, seed protein concentration and then compare phenotypic selection (PHE) and MAS approaches for seed yield and protein concentration improvement. Two hundred and eighty two F5 derived recombinant inbred lines (RILs) were developed from a cross of Essex × Williams 82 and genotyped with 1586 single nucleotide polymorphism (SNP) markers. The population was divided by days to maturity (10 days) into three tests (early, mid and late) each with 94 genotypes, with one genotype overlapping in maturity in the mid and late tests. In 2009, the three tests, parents and checks were grown in a randomized complete block design (RCBD) in: Fayetteville, AR; Harrisburg, IL and, Knoxville, TN replicated three times, and evaluated for seed yield and protein concentration. Data were combined within each test across three locations and analyzed using the MIXED procedure of SAS to determine that there were significant genotypic differences among RILs. Composite interval mapping (CIM) detected nine seed yield and ten protein concentration QTL which may be good candidates for MAS as they were environmentally stable. Selections to compare PHE, and MAS for seed yield and protein concentration provided 8 replicated field tests in four relative maturity groups grown in a RCBD replicated three times in three locations in Tennessee, in 2010. We demonstrated that both MAS and PHE may be used to select quantitative traits; however, more studies are required to optimize MAS for quantitative trait improvement. 

Wholegrains have been linked with significant health benefits such as management of cardiovascular disease, diabetes and some cancers. This study aimed to add value to the grain industry by exploring new nutraceutical targets. This was achieved using bioassay guided fractionation. Wheat extracts including wholegrain, endosperm, pericarp and aleurone from different commercial varieties were investigated for in vitro bioactivity in antioxidant, glycosidic enzyme inhibition, anti-inflammatory, anti-cancer, immune function and cholesterol lowering assays. This study found wheat to have antioxidant activity as measured by oxygen radical absorbance capacity (ORAC) assays with higher values reported for the wheat bran extracts. Amino acid trytophan was identified as the most dominant antioxidant compound in the hard wheat variety durum with a TE value of 24217 ± 3158 µmol/g compound. The unsaturated fatty acids oleic, linoleic and linolenic acids proved to be responsible for the majority of the antioxidant activity in the hard wheat bran H2 with TE values of 2424 ± 274, 5220 ± 523 and 5542 ± 102 µmol/g compound, respectively. Wheat bran and germ but not wholegrain or endosperm displayed α-glucosidase and α-amylase inhibiting properties. Through bioassay guided fractionation, phosphoglycerides, 1,2-linoleoylglycero-3-phosphate and 1-palmitoyl-2-linoleoylglycero-3-phosphate were deemed responsible for the α-glucosidase inhibition. Crude wheat extracts were not cytotoxic to a number of human cancerous cell lines. However, some specific fractions showed selective cytotoxicity to the PC3 human prostate tumour cell line. These fractions contained a number of alkylresorcinols with comparative IC50 values (µg/mL) 5-(2-oxotricosanyl)resorcinol (10.9), trans 5-(14-nonadecenyl)resorcinol (13.7), 5-heptadecylresorcinol (22.5) and trans 5-(16-heneicosyl)resorcinol (42.2) to the known anti-cancer agent Chlorambucil (58.7). In this study, wheat bran extracts have not shown any anti-inflammatory inhibition, estrogen binding inhibition, cholesterol lowering or immune function activity. Wheat bran has proved to be a highly nutritious by-product of the wheat milling industry with a number of protective health effects

Pollen grains serve a very important role in the life cycle of flowering plants, in that they are involved in the transmission of inherited characteristicsfrom generation to generation. Because of their small size the study of pollen grains has been necessarily associated with the development of the microscope. Not until the middle of the seventeenth century, when Hooke gave the world the compound microscope, was an instrument available with sufficient power to adequately reveal the shapes of pollen grains. However , two of Hooke's contemporaries, Malpighi and Grew, who used a simple microscope , are generally recognized as the co-founders of pollen grain morphology.

The purpose of this study was to examine the molecular evolution of floral developmental MADS-box genes in diploid and allotetraploid cotton (Gossypium, Malvaceae). We isolated and characterized both cDNA and genomic DNA sequences of four MADS-box genes, B-sister, APETALA3 (AP3), PISTILLATA (PI, two copies) and AGAMOUS (AG), in seven Gossypium species (2 A-genome species, 2 D-genome species, 1 C-genome species and 2 AD-genome species) as well as an outgroup species, Gossypioides kirkii. We then studied the expression patterns of each gene by reverse-transcriptase PCR (RT-PCR) in each flower part for different flower stages of G. arboreum (A-genome), G. raimondii (D-genome) and G. hirsutum (AD-genome). We found that these MADS-box genes are evolving independently at the DNA sequence level but exhibit highly variable expression patterns in allotetraploid G. hirsutum. These MADS-box genes contain highly conserved exon lengths and exon/intron structures, high nucleotide identity with homologs in Arabidopsis thaliana and Antirrhinum majus, and conserved gene phylogeny within the genus Gossypium. All the genes exhibit evidence of codon bias. The AP3 gene in Gossypium appears to be subject to positive selection, while the PI-small copy of the PI gene appears to be subject to strong functional constraints together with a very low mutation rate. Within G. hirsutum, the B-sister gene exhibits gene silencing of the A-subgenomic homoeolog and the PI-big copy of the PI gene has experienced pseudogenization by insertion of a copia-like retroelement. The AP3, PI-small and AG genes show biased expression patterns in G. hirsutum. These MADS-box genes also demonstrated developmentally regulated expression patterns in G. arboreum, G. raimondii and G. hirsutum.

Barley is one of the world's most important food and feed crops. It is adapted to a wide range of environments. According to Harlan and Martini (1936) barley is grown from north of the Artic Circle to the sands of the Sahara, and from the slopes of Mt. Everest to the lower delta of the Nile. Considerable progress has been made in its improvement through plant breeding. Barley is one of the best cultivated crop plants for use in genetic studies. It is a diploid plant from the family Gramineae with seven pairs of chromosomes. The cultivated species are interfertile and have a large number of readily distinguishable genetic characters. Approximately 370 characters are recognized (Nilan, 1964). Many of Barley's genes have been mapped and assigned to one of the seven chromosomes. Linkage groups in barley have been designated in a number of ways. A Roman numeral was used extensively in the earlier studies to identify each linkage group. More recently an Arabic number system has been used. This system was adopted by the Fourth Annual Barley Research Worker's Conference and will be followed in this study. The study involves 24 contrasting factors and was undertaken to determine the location of certain genes already reported in specific linkage groups and, if possible, to assign several previously unassigned genes to linkage groups. Of the 24 factor pairs studied, six have not yet been assigned to a chromosome. The inheritance and linkage associations of these unassigned genes receive major emphasis in this study.

With over 300,000 plant species on the planet and more than 90% of them relying on pollen for reproduction, palynology, the study of pollen grains plays a vital role in many research fields. One of them is forensic palynology, which uses pollen as a proxy to link individuals or objects to a location or instance. It relies on the fact that (1) pollen is an ever-present feature of the environment; (2) different locations have different pollen signatures, allowing for inference related to spatial tracking; (3) plants bloom at different times, allowing for temporal inference; and (4) pollen is exceptionally durable and can be used for forensic studies decades after sample collection. In addition, forensic palynology has played a role in many criminal investigations, mainly investigations dealing with homicide, violent assault, rape, genocide, terrorism, and suspected terrorism. Identifying plant species from their pollen relies on two traditional methods: microscopy or genetic analysis. On the one hand, microscopy relies on identifying pollen grains using their morphology (i.e., size, shape, and wall structure) and comparing it to an image library for accurate identification. On the other hand, genetic analysis characterizes pollen species using a short DNA sequence from a universal standard in the genome. Both methods have so far been mutually exclusive. The standard procedure for microscopy is to clean the grain through acetolysis, which destroys any genetic material in the sample. Studies involving genomic characterization of the plant material require the release of the genomic material by mechanically crushing the grain, which can no longer be analyzed for morphology through microscopic methods. While the number of forensic palynological studies increases, they usually rely on only one of the two techniques above and rarely show the potential for an efficient analysis of individual grains within an assemblage to statistically evaluate the species distribution in the mixture of grains that can be the evidence. During this Ph.D. research, a new method for pollen DNA extraction was developed that does not destroy the pollen grain, getting around both crushing and acetolysis approaches. After evaluating the non-destructive nature of the new protocol by microscopy, single pollen grains from a variety of common species were examined using universally accepted genetic markers (rbcL, matK, and ITS2) for DNA analysis. The sequencing of the different species was also performed and discussed to evaluate the potential for single species identification from databases. Finally, the developed approach for non-destructive DNA extraction was evaluated on a complex object, a car cabin air filter, showing how microscopic plant evidence (pollen and debris) analysis can easily provide information in an investigation.

Barley is an economically important cereal crop throughout most of the world. The study and elucidation of the genetic complex of this plant will add to its extensive usefulness to man, and will also provide valuable information for similar research projects on other crop plants.

The colors of the glumes on wheat have been described as being white, yellow, brown, or black. The white actually ranges from cream or pale straw-yellow to dark yellow. Some varieties have white or yellow glumes with brown or black nerves.