Graduation date: 1995

Graduation date: 1982

To remain competitive in the international marketplace, soft white wheat cultivars grown in the Pacific Northwest must have consistent and predictable flour properties including kernel texture. As a consequence, there is a need to develop wheat cultivars for specific end uses. Wheat cultivars with very soft kernels are used largely for making cookies and cakes. Harder soft white wheats are more suitable for noodles and flat breads. Numerous studies have been made to determine the inheritance of kernel texture between hard and soft wheat; however, very little information is available concerning the amount of genetic variability within soft white wheat. Reciprocal crosses were made between a very soft (TJB/MON"S") and a soft (Yamhill) white winter wheat genotype. Data were collected on an individual plant basis for kernel texture, protein content, and eight selected agronomic traits. Kernel hardness and protein content were determined using the near-infrared reflectance spectroscopy (NIR). Genetic differences for kernel texture and the other nine traits were found between the two parents and the resulting F1 progenies. It would appear that kernel texture is qualitatively inherited with one or more genes reflecting additive and nonadditive gene action. However, a large component of non-genetic variation was also detected. Of particular interest was the apparent reciprocal differences found between Fl populations for most of the traits measured and particularly kernel texture. However, for kernel texture, such differences were not due to a dosage effect of the 3n endosperm. Kernel texture was not found to be associated with protein content. A negative association of kernel texture with heading date would suggest a compromise may be necessary when selecting these traits. Positive associations were found between kernel hardness with number of tillers, total biological yield, grain yield, and number of kernels per spike. / Graduation date: 1992

This study analyzes the impact of the 1980 Staggers Rail Act (SRA) on Pacific Northwest (Oregon, Washington, Idaho and Montana) wheat transportation. A minimum cost uncapacitated transshipment network flow model is employed to simulate the origination and destination pattern of grain flows before (1977) and after (1985) the SRA. The grain transportation flow for those two years is compared and analyzed as a basis for measuring the impact of rail deregulation. The Transportation Simplex Algorithm is used to find the optimum (minimal cost) wheat transportation flow for the two time periods. Four modes of transportation—truck, barge, rail, and ocean carriers—are used to link a sample of inland grain elevators (source), barge terminals (transshipment), PNW ports on the Lower Columbia River and Puget Sound (transshipment), and foreign countries (sink). The empirical results indicate that the SRA has had a significant impact on modal distribution, overall transportation costs, and rate competition. Under the assumption of perfect information and profit maximizing behavior, and considering both single car and multicar rates, two-thirds of the total PNW wheat traffic should have moved by rail in 1985. This represents a significant increase compared to 1977, when this percentage was estimated at only 46.43 percent. This increase in rail modal share has come at the expense of truck-barge shipments. The truck-barge share of wheat transportation declined from 47.53 percent in 1977 to 25.66 percent in 1985. Most of this increase in rail shipment is the result of lower shipping costs offered through multicar rates. If only single car rail rates are considered in 1985, the rail market share is only 25.66 percent; while truckbarge market share is 66.60 percent. The volume of wheat exported through the Lower Columbia River ports and Puget Sound appears not to have been affected by the SRA. Overall wheat transportation cost decreased significantly over this time interval. In nominal terms, it cost an average of 5.32 percent less in 1985 than in 1977 to transport a metric ton of PNW wheat to the port terminals on the west coast. When adjusted for inflation, average wheat transportation cost decreased around 44 percent. Sensitivity analysis showed that the wheat transportation market in the PNW has been very competitive since 1977 with some apparent changes in market behavior. First, railroads had a greater ability in 1985 than in 1977, to capture wheat traffic from truck-barge by lowering rates. When rail rates are reduced by one percent, rail traffic increases 7.93 percent in the 1985 model and only 2.40 percent in the 1977 model. Rail rate increases, on the other hand, lead to higher traffic losses in 1977 than in 1985. For an increase of one percent in rail rates, rail traffic decreased 10.21 percent in 1977, and only 4.76 percent in 1985. The conclusion of this study is that there has been a significant diversion of wheat traffic from truck-barge to rail, during the period of rail deregulation. Overall transportation costs have also decreased, and the railroads ability to capture wheat traffic by reducing rates has been enhanced. It is concluded that the impact of the SRA on PNW wheat transportation is due largely to the introduction of multicar rates by the railroads serving the region. The implications of these findings are that railroad deregulation has provided many of the benefits expected by this legislation. Shippers are favored by the SRA because they are paying lower transportation costs. Railroads have benefited, to the extent that their market share has increased. Barge companies, however, have been adversely influenced by the SRA because they have lost their modal share of wheat traffic to railroads. Shippers, while benefiting from lower rates, seems now more vulnerable to the potential for future rail rate increases. / Graduation date: 1987

Wheat breeders must effectively maintain and manage existing genetic diversity in order to continue the development of superior genotypes. It is therefore fundamental that the genetic relationships and diversity within the germplasm pools be thoroughly characterized and understood. Recently, DNA-based markers have provided powerful tools for genetic diversity analysis. This study investigates the usefulness of nuclear and chloroplast simple sequence repeat (SSR) markers in characterizing Pacific Northwest wheat (Triticum aestivum) breeding germplasm, and explores the patterns of genetic relatedness revealed by these markers. The 15 chloroplast SSRs were effective in differentiating between B-type, D-type, and barley (Hordeum vulgare) cytoplasms. Genetic distance estimates were determined for each pair of lines studied and analyzed using UPGMA clustering. The markers revealed five plastomic types within the B-type cytoplasm studied. Several lines of wheat in this germplasm, including important PNW cultivars like Madsen, were found to contain D-type cytoplasm rather than the B cytoplasm of wheat. Nuclear SSR assays using 24 markers revealed three major clusters of germplasms: PNW soft white winter wheat, Western European-derived lines, and Great Plains accessions, as well as two clusters of more distantly related lines and genetic stocks. The primary defining characteristic of these clusters was regional adaptation. Subgroups of these major groups often clustered together on the basis of pedigree and market class. When nuclear and chloroplast SSR data was combined in analysis, the primary defining characteristic of the dendrogram became the type of cytoplasm rather than regional adaptation, with secondary divisions based on pedigree relationships. Cultivars released prior to 1950 were found to have a minimum of 20% of alleles in common for nuclear and chloroplast data combined, despite being unrelated via pedigree information. Heterogeneity was 2.3% for all marker/variety combinations. Overall, these sets of markers were found to be effective in characterizing the genetic relatedness of PNW wheat breeding germplasm. / Graduation date: 2003

Despite many investigations genotype by environment interaction remains one of the least understood factors in plant improvement. Understanding genotypic differences responsible for such interactions could assist in making more informed breeding decisions. The components of yield being less complex than grain yield per se may be useful for selection to improve adaptation of genotypes and enhance grain quality. However, the potential compensatory response among the components of yield could compromise their usefulness as selection criteria. To evaluate this aspect fifteen cultivars, including Soft White, Hard White and Hard Red wheats, were planted at three diverse locations over two growing seasons. Genotypes were ranked based on measurements for specific traits in each environment. The genotype by environment interaction for grain yield, protein concentration and hardness were investigated according to the AMMI model. Influence of environmental factors and genotype by environment interactions on associations among selected traits were determined. The results of this study showed that genotypic differences in adaptation to the Pacific Northwest and resistance to Septoria spp. were responsible for interactions for grain yield. However, no consistent patterns of response were found among the similar cultivars for quality traits. Those environments that favored expression of biomass and grain weight potential provided for enhanced performance of the adapted cultivars. The environments with suppressed biomass accumulation and grain filling interacted positively with the unadapted cultivars. A large compensatory relationship between tillering and apical growth was detected. No or low compensation was observed between grains per spike and thousand kernel weight. Two different strategies were proposed for improvement of Soft and Hard White wheat cultivars under the conditions of the Pacific Northwest. Both strategies accentuate importance of increasing biomass while maintaining harvest index. When selecting for higher yielding Soft White cultivars, plants with larger leaves, stronger stems, larger spikes and heavier grains should be emphasized. For Hard Whites - higher number of tillers and grains m����� is desired, as they provide for harder grains with higher protein content. / Graduation date: 2000

Jointed goatgrass (Aegilops cylindrica Host) infestations in winter wheat (Triticum aestivum L.) production regions of the central and western USA result in severe economic losses in the wheat market. Field and greenhouse studies were conducted to determine the vernalization requirements of winter wheat, spring wheat, jointed goatgrass, and wheat by jointed goatgrass reciprocal hybrid plants. In field studies, jointed goatgrass plants required more vernalization to produce spikelets and germinable seed than 'Madsen' winter wheat plants. In greenhouse studies, plants of jointed goatgrass populations collected from Oregon and Washington wheat fields required fewer vernalization days to reach the joint stage than Madsen plants. Detailed observations in the greenhouse revealed a longer period between jointing and anthesis for most jointed goatgrass populations that was overlooked in field studies. Vernalization for 6-wk represents the minimum treatment for synchronous reproductive development among jointed goatgrass populations, Madsen winter wheat, and Madsen by jointed goatgrass hybrids, yet the risk of gene transfer might be greater after 7-wk vernalization. In the jointed goatgrass populations tested, there was not selection for a vernalization insensitive growth habit. Because jointed goatgrass spikelets often contain two seed, germination was recorded for primary and secondary positioned seed. Germination of freshly harvested jointed goatgrass seed was promoted by 25/15 C day/night temperatures. However, light and 30/20 C incubation was necessary for maximum germination of non-dormant, primary positioned seed. Both primary and secondary positioned seed within jointed goatgrass spikelets were non-dormant after 16-wk after-ripening at 22 ± 2 C. Under optimum growing conditions, no planting depth selectively allowed wheat germination and emergence while preventing jointed goatgrass germination and emergence. Glume removal did not alleviate dormancy completely in jointed goatgrass seed. Research confirmed jointed goatgrass population polymorphism for vernalization requirements and seed dormancy. Jointed goatgrass reproductive variability might be part of a general purpose genotype strategy to germinate and colonize a wide range of environments. Wheat by jointed goatgrass hybrid plants should be removed from winter and spring wheat fields. Despite a short dormancy period, three or more years of rotation outside of winter annual crops may be necessary to reduce populations of jointed goatgrass. / Graduation date: 2006