Doctor of Philosophy / Department of Agronomy / Gina Brown-Guedira / Allan K. Fritz / Aegilops tauschii, the D-genome donor of modern wheat, has served as an important source of genetic variation in wheat breeding. The objective of this research was to characterize and utilize multiple Ae. tauschii-derived pest resistance genes contained in the germplasm KS96WGRC40. Two Ae. tauschii-derived genes, H23 and Cmc4, provide resistance to the Hessian fly (HF) and wheat curl mite (WCM), respectively. A linkage analysis of a testcross population estimated 32.67% recombination between H23 and Cmc4 on chromosome 6DS in wheat indicating that the two genes are not tightly linked as previous mapping reports show. Haplotype data of recombinant lines and physical mapping of linked microsatellite markers located Cmc4 distal to H23. Haplotype data indicated that both KS89WGRC04 and KS96WGRC40 have the distal portion of 6DS derived from Ae. tauschii. Microsatellite primer pairs BARC183 and GDM036 were more useful than the previously published linked markers in identifying lines carrying Cmc4 and H23, respectively. Through phenotypic selection and advancement within the testcross population, three TC1F2:4 lines were identified as homozygous resistant for H23 and Cmc4 and have the complete terminal segment of 6DS from Ae. tauschii. Two lines are more desirable than the original germplasm releases and can serve as a source of resistance to both HF and WCM in an elite background. A linkage analysis of a segregating recombinant inbred line population identified an Ae. tauschii-derived gene of major effect conferring resistance to Septoria leaf blotch (STB) and another Ae. tauschii-derived gene of major effect conferring resistance to soil-borne wheat mosaic virus (SBWMV) in the germplasm KS96WGRC40. The STB resistance gene in KS96WGRC40 is located in the distal 40% of the short arm of chromosome 7D flanked by microsatellite markers Xgwm044 and Xbarc126. Two previously reported STB genes, Stb4 and Stb5, have been mapped to 7DS in the same region as the STB resistance gene in KS96WGRC40. The uniqueness of the STB resistance genes on 7DS is questionable. The SBWMV resistance gene in KS96WGRC40 is located on chromosome 5DL linked to microsatellite marker Xcfd010. The SBWMV resistance gene within KS96WGRC40 was derived from TA2397 via KS95WGRC33.

Doctor of Philosophy / Department of Agronomy / Stephen J. Thien / Range and Training Land Assessment (RTLA) and Land Rehabilitation and Maintenance (LRAM) are key components of The United States Army's Integrated Training Area Management (ITAM) Program, which outlines its commitment to support the sustainable use of military training lands. The primary purpose of the RTLA Program is to provide information and recommendations regarding the condition of training lands to range managers for scheduling of training areas and monitoring the effectiveness of rehabilitation projects. The goal of the LRAM component of ITAM is to reduce the long-term impacts of training on installations through the implementation of improvements to vegetation cover and repairs to landscape damage in disturbed areas. Fort Riley Military Installation, located in the largest remaining expanse of tallgrass prairie in the Flint Hills of northeastern Kansas, is a major training reservation, with seventy percent of its 40,434 ha used for mechanized maneuvers. A randomized complete block design composed of M1A1 tank traffic in a figure-eight pattern during wet and dry soil conditions was established in each of two soil types, a silty clay loam and a silt loam, and recovery of physical, chemical, and biological indicator variables was monitored from 2005 through 2007. In a second study, the effectiveness of LRAM procedures, including leveling, mulching, and reseeding, was evaluated following wheeled vehicle disturbance. The goals of this study were to identify disturbance indicators appropriate for assessing soil quality and, based on the status of these indicators, develop a method for modeling the stage and rate of ecological degradation and potential response to remediation. Disturbance increased significantly during wet compared to dry soil conditions, for increased traffic intensity, and for curve compared to straight-a-way areas in both soil types. The greatest impacts were on above and below ground community structure, providing an effective bioindicator of ecosystem health for military training land managers. Remediation of wheeled vehicle disturbance with leveling and mulching, but not reseeding, increased total vegetation production. The tallgrass prairie typically is considered to be among the most resilient of military training lands, but resiliency is dependent upon soil type and training conditions, and may require longer periods of recovery than previously thought.

Master of Agribusiness / Department of Agricultural Economics / Arlo Biere / The investors I am representing would like to know if they can be successful in the seed industry. They have certain skills and abilities along with industry experience that provides them with certain advantages that would allow them to succeed in the industry. The thesis or study will provide them with a detailed study of the possibilities and the challenges that are before them. To gain insight into positioning a firm in the industry, one must find a tool to help us to discover the answers to the question. I will use "Strategic Visioning in Cascade", this model outlines area of interest such as; a strategic overview, a value proposition, a market analysis, a functional analysis, financial projection and exit strategy in its total. The focus of the study will provide insight into the value proposition and market analysis. The value proposition will follow Michael Porter's Competitive Strategy analogy of cost leadership, differentiation and focus strategies. The market analysis will follow Thompson and Strickland's seven questions that lead to understanding of the selected industry.

Master of Science / Department of Agronomy / Jay M. Ham / The potential environmental impact of animal feeding operations on air quality has created the need for accurate air emissions measurements. Of particular concern are ammonia emissions from cattle feedlots, operations that contribute a large portion of the agricultural ammonia emissions inventory. Micrometeorological methods are ideal for emissions measurements from large, open-source areas like feedlot pens; however, theoretical assumptions about the boundary layer must be made, which may not hold true above the heterogeneous, fetch-limited surface of the feedlot. Thus, the first objective of this work was to characterize the surface boundary layer of an open-air cattle feedlot and provide insight into how micrometeorological techniques might be applied to these non-ideal sites. Eddy covariance was used to measure fluxes of momentum, heat, water, and carbon dioxide from a commercial cattle feedlot in central Kansas. Data supported the use of eddy covariance and similar methods (i.e., relaxed eddy accumulation) for flux measurements from both cattle and pen surfaces. The modeled cumulative source area contributing to eddy covariance measurements at a 6 m sample height was dominated by just a few pens near the tower, making the characteristics of those pens especially important when interpreting results. The second objective was to develop a system for measuring ammonia fluxes from feedlots. A new type of relaxed eddy accumulation system was designed, fabricated, and tested that used honeycomb denuders to independently sample ammonia in up-moving and down-moving eddies. Field testing of the relaxed eddy accumulation system at a feedlot near Manhattan, KS showed fluxes of ammonia ranged between 60 and 130 μg m-2 s-1 during the summer of 2007. Even in the high ammonia environment (e.g., 300-600 μg m-3), the honeycomb denuders had enough capacity for the 4-hour sampling duration and could be used to measure other chemical species that the denuders could be configured to capture. Results provide a foundation for emissions measurements of ammonia and other gases at cattle feedlots and help address some of the challenges that micrometeorologists face with any non-ideal source area.

Master of Science / Department of Agronomy / Ganga M. Hettiarachchi / Phosphorus (P) management in reduced tillage systems has been a great concern for farmers. Conclusive results for benefits of deep banding of P fertilizers for plant yield in reduced tillage system are still lacking. Knowledge of the dominant solid P species present in soil following application of P fertilizers and linking that to potential P availability would help us to design better P management practices. The objectives of this research were to understand the influence of placement (broadcast- vs. deep band-P or deep placed-P), fertilizer source (granular- versus liquid-P), and time on reaction products of P. Greenhouse and field based experiments were conducted to study P behavior in soils. Soil pH, resin extractable P, total P, and speciation of P were determined at different distances from the point of fertilizer application at 5 weeks (greenhouse and field) and 6 months (field) after P application (at rate 75 kg/ha) to a soil system that was under long-term reduced tillage. X-ray absorption near edge structure spectroscopy technique was used to speciate reaction products of fertilizer P in the soil. The reaction products of P formed upon addition of P fertilizers to soils were found to be influenced by soil pH, P placement methods, and P sources. Acidic pH (below~5.8) tended to favor formation of Fe-P and Al-P like forms whereas slightly acidic near neutral pH soils favored formation of Ca-P like forms. Scanning electron microscope with energy dispersive X-ray analysis of applied fertilizer granules at 5-wk showed enrichment of Al, Fe and Ca in granule- indicating these elements begin to react with applied P even before granules dissolve completely. The availability of an applied P fertilizer was found to be enhanced as a result of the deep banding as compared to the surface broadcasting or deep placed methods. Deep banded liquid MAP was found to be in more adsorbed P like forms and resulted greater resin extractable P both at 5 wk and 6 month after application. Deep banding of liquid MAP would most likely result both agronomically and environmentally efficient solution for no-till farmers.

Doctor of Philosophy / Department of Agronomy / Kassim Al-Khatib / Mitchell R. Tuinstra / Sorghum acreage is declining throughout the United States because management options and yield have not maintained pace with maize improvements. The most extreme difference has been the absence of herbicide technology development for sorghum over the past twenty years. The objectives of this study were to evaluate the level of resistance, type of inheritance, and causal mutation of wild sorghums that are resistant to either acetyl-coenzyme A carboxylase (ACCase)-inhibiting herbicides or acetohydroxyacid synthase (AHAS)-inhibiting herbicides. ACCase-inhibiting herbicides used in this study were aryloxyphenoxypropionate (APP) family members fluazifop-P and quizalofop-P along with cyclohexanedione (CHD) family members clethodim and sethoxydim. The level of resistance was very high for APP herbicides but low to nonexistent to CHD herbicides. With genetic resistance to APP herbicides, the resistance factors, the ratio of resistance to susceptible, were greater than 54 to 64 for homozygous individuals and greater than 9 to 20 for heterozygous individuals. Resistance to CHD herbicides was very low with resistance factors ranging from one to about five. Genetic segregation studies indicate a single gene is the cause of resistance to APP herbicides. Sequencing identified a single mutation that results in cysteine replacing tryptophan (Trp-2027-Cys). Trp-2027-Cys has previously been reported to provide resistance to APP but not CHD herbicides. The other wild sorghum evaluated in this study was resistant to AHAS-inhibiting herbicides including imidazolinone (IM) family member, imazapyr, and sulfonylurea (SU) family member, nicosulfuron. Resistance factors in this genotype were very high, greater than 770 for the IM herbicide and greater than 500 for the SU herbicide, for both herbicide chemical families. Genetic segregation studies demonstrate that resistance was controlled by one major locus and two modifier loci. DNA sequencing of the AHAS gene identified two mutations, Val-560-Ile and Trp-574-Leu. Val-560-Ile is of unknown importance, but valine and isoleucine are similar and residue 560 is not conserved. Trp-574 is a conserved residue and Leu-574 is a known mutation that provides strong cross resistance to IM and SU herbicides. The results of these studies suggest that these sources of APP, SU, and IM resistance may provide useful herbicide resistance traits for use in sorghum.

Doctor of Philosophy / Agronomy / Allan K. Fritz / Bikram S. Gill / Gary M. Paulsen / Post-anthesis high temperature stress in wheat (Triticum aestivum L.) is a major cause of yield reduction. This process results in the loss of viable leaf area and a decrease in green leaf duration ultimately causing a yield loss. The objectives of this study were to (i) phenotype a recombinant inbred line population for heat tolerance traits, (ii) understand the genetic basis of heat tolerance by mapping quantitative trait loci (QTL) linked to yield-related traits under high temperature, (iii) model stay-green under high temperature stress and map the QTL linked to stay-green parameters, and (iv) validate the markers linked to QTL under field conditions. A filial6:7 (F6:7) recombinant inbred line (RIL) population was developed by crossing Ventnor, a heat-tolerant white winter wheat with Karl 92, a relatively heat susceptible hard red winter wheat. From 10 DAA to maturity, the treatments of optimum temperature or high temperature stress (30/25°C) were imposed on the RILs. The traits measured included grain filling duration (GFD), kernels per spike, thousand kernel weight (TKW), and grain filling rate (GFR). The stay-green traits calculated were: i) time between 75% and 25% green, ii) maximum rate of senescence, iii) time to maximum rate of senescence, and v) percent green at maximum senescence. Genetic characterization was performed using microsatellite (SSR), amplified fragment length polymorphism (AFLP) and a sequence tag site (STS) markers. GFD was positively correlated with TKW and negatively with GFR and maximum rate of senescence. Principle component analysis (PCA) showed kernels per spike, maximum rate of senescence, and TKW accounted for 98% of total variability among the genotypes for heat tolerance. The most significant QTL for yield traits co-localized with marker Xgwm296 for TKW, Xgwm356 for kernels per spike, and Xksum61 for GFR. The QTL for stay-green traits co-localized with markers P41/M62-107 on Chromosome 2A, Xbarc136 on Chromosome 2D, P58/MC84-146 on Chromosome 3B, P58/M77-343 on Chromosome 6A, and. P58/MC84-406 on Chromosome 6B. These results indicate that increased green leaf area duration has a positive effect on the grain yield under high temperature. Once the kernels per spike are established, GFD and TKW can be used as selection criteria for post-anthesis heat-tolerance.