Sorghum is the fifth most important cereal crop in the world and ranks third in Africa, and it is potentially the number one cereal for the semi-arid environments in sub-Saharan Africa. Sorghum varieties have been developed specifically for grain, fodder or stem sugar but not for dual-purpose combining grain and stem sugar. Such varieties could be beneficial to the resource-poor farmers by providing grain for food and sugar rich stalks that can be sold for bioethanol production. However, there are no suitable dual-purpose cultivars on the market. There is also limited information about the combining ability, gene action and genetic effects and relationships between stem sugar and grain yield which is required in devising appropriate strategies for developing dual-purpose sorghum varieties. Furthermore, there is also lack of information about the perceptions of resource-poor, small-scale farmers and other important stakeholders on the potential of dual-purpose sorghum production and the value chain. Therefore, the objectives of this study were to: (i) investigate the awareness of the farmers, industry and other stakeholders on the dual-purpose sorghum varietal development and its feasibility, (ii) screen germplasm for use as source materials useful for grain yield and stem sugar traits, (iii) investigate the inheritance and heterosis levels attainable in grain yield components and stem sugar traits in dual-purpose sorghums, (iv) determine the relationships between stem sugar traits and grain yield components in dual-purpose sorghums, and (v) investigate the fertility restoration capacities of selected male-fertile lines used as male parents through the evaluating seed set in experimental dual-purpose hybrids. Two surveys were conducted to establish stakeholders’ level of awareness and perceptions on the potential and feasibility of developing and utilising dual-purpose sorghums in Southern Africa. One survey was carried out in the semi-arid tropical lowlands in Zimbabwe under the conditions of small-scale and resource-poor farmers while the other, which targeted sugar industries, plant breeders, engineers, political leaders, economists and extension workers, was conducted in South Africa and Zimbabwe. Data were analysed using SPSS computer package. Results showed that both farmers and the non-farmer stakeholders were in agreement on the view that dual-purpose sorghum would be a viable enterprise that could alleviate poverty, enhance food security, create rural employment and boost rural development in southern African countries. Farmers were willing to adopt the cultivars if they were made available. The stakeholders also suggested mechanisms to overcome the infrastructural, economic and technical challenges associated with the technology. Screening of regional and international germplasm collection held at the University of KwaZulu- Natal in South Africa revealed high genetic variability for grain yield, stem brix and stem biomass yield that can be exploited in dual-purpose sorghum cultivar development. Ten lines were selected for inclusion as parents in the dual-purpose sorghum breeding programme. The selections were crossed to eight cytoplasmic male-sterile lines originating from the International Crops Research Institute for the Semi-Arid Tropics (ICRISAT) in accordance with a North Carolina Design II mating scheme. The 18 parents, together with the 80 experimental hybrids generated and two check varieties were evaluated for grain yield and stem sugar traits in six tropical low- and mid-altitude environments in Mozambique, South Africa and Zimbabwe. Stem sugar concentration and stem biomass were measured at the hard dough stage of each entry due to maturity differences between the genotypes. Grain yield was measured and adjusted to 12.5% moisture content. Data were analysed in GenStat computer package following a fixed effects model. Both additive and non-additive gene effects were important in controlling stem brix, stem biomass, grain yield and the associated traits in dual-purpose sorghum. This showed that breeding progress can be achieved through hybridisation and selection. Cultivars showing high stability, and high standard and better-parent heterosis for the three traits were identified implying that breeding for general adaptation was an option and that productivity could be enhanced by breeding hybrid cultivars. The relationships between traits were estimated using correlation and path-coefficients analysis. Grain yield was found to be negatively and significantly associated with stem brix but was positively and significantly associated with stem biomass. This implied that breeding for high stem brix might compromise grain yield but selection for high stem biomass improved grain yield. Stem biomass and stem brix were not significantly correlated. The general negative relationship between grain and stem brix was attributed to the predominance of entries with contrasting performances for the two traits. However, the relationship between grain yield and stem brix of the top 20 performing entries showed a non-significant relationship between stem brix and grain yield suggesting that the traits were independent of each other. This finding was confirmed by the presence of crosses that combined high performance for both stem brix and grain yield as well as stem biomass among the hybrids. The relationships between stem brix and stem biomass for the top 20 performers remained non-significant while that between stem biomass and grain yield became stronger, positive and significant. Direct selection for stem brix and grain yield was shown to be more important than indirect selection, while selection for stem biomass improves grain yield but had no effect on stem brix. Therefore, it is possible to breed dualpurpose sorghum cultivars and the identification of genotypes combining the desirable traits is prudent in addition to general relationships information. The study on fertility restoration capacities as evaluated through hybrid seed set showed that fertility restoration was under the control of genes with both additive and non-additive action. Since restoration is conferred by a single dominant gene (Rf1), this could have arisen from the action of the modifier genes that have been previously reported to influence it. This showed that fertility restoration can be improved through breeding. Hybrid combinations showing complete seed set and high performance for grain, stem brix and stem biomass were identified and are potential dual-purpose sorghum cultivars. Overall, the study showed that development of dualpurpose sorghum cultivars would be feasible and genotypes identified as potential cultivars in this study will be forwarded for further testing across many sites and seasons in the target environments. / Thesis (Ph.D.)-University of KwaZulu-Natal, Pietermaritzburg, 2009.

Striga, a genus of obligate parasitic weeds in the family Orobanchaceae, has been identified as the most important biological factor limiting agricultural productivity in sub-Saharan Africa. Germination of Striga seeds is triggered by strigolactone root exudates from host plants. Strigolactones also induce hyphal branching in arbuscular mycorrhizal (AM) fungi, which are important for plant uptake of phosphorus in low phosphorus soils. Mechanisms of Striga resistance based on reduced strigolactone production may also convey resistance to AM fungi which would require higher inputs of phosphorus fertilizer to attain optimal crop growth. There is evidence for genetic differences in mycorrhizal responsiveness in other grain crops; therefore it is beneficial for breeders to be aware of these differences when developing Striga-resistant sorghum cultivars. This research aims to determine phosphorus and mycorrhizal responsiveness of sorghum genotypes important for or developed by breeders working on Striga resistance. Phosphorus response curves were determined for twelve sorghum genotypes using pasteurized low phosphorus soil amended to achieve four different phosphorus levels. Simple linear regression was performed on root and shoot dry weight data. Results indicate variability in phosphorus responsiveness within Striga resistant and susceptible genotypes. Seven of these genotypes were selected for continued research, which analyzed responsiveness to phosphorous and differences in mycorrhizal responsiveness in relation to reported mechanisms of Striga resistance. Treatments included three levels of phosphorus amendments and the addition of Funneliformis mosseae inoculum. All genotypes were strongly responsive to P amendment when grown without AM fungi and showed a decrease in responsiveness to P when inoculated with F. mosseae. Trends for all genotypes indicate a greater uptake of P, Zn, and Mg by mycorrhizal plants as compared to nonmycorrhizal plants. All seven genotypes were responsive to mycorrhizae, with a significant increase in biomass for all genotypes, especially at the lowest phosphorus level. The responsiveness to the mycorrhizal fungus does not appear to be directly related to the susceptibility of genotypes to the parasitic weed Striga. / Graduation date: 2012

During 2013 and 2014, studies were conducted to determine the effects of Helicoverpa zea and Spodoptera frugiperda on both damage and yield of Sorghum bicolor. Results from damage ratings suggest that the amount of damage per single larva decreases as population density increases. Also, yield results suggest that one H. zea and one S. frugiperda larva per panicle results in a 3.6 and 4 percent yield loss, respectively. Additionally, a dynamic EIL was determined using crop value along with various yield potentials and control costs. Other research studies were conducted to determine the efficacy of diamide and pyrethroid insecticides on headworms when applied at midge timing for different locations and planting dates. Results suggest that diamides provide longer and better control of headworms than do pyrethroids. However, applying diamides as a preventative application at midge timing may not be economically feasible when grain prices are low.

Doctor of Philosophy / Department of Grain Science and Industry / Sajid Alavi / Sorghum grain (Sorghum bicolor) is safe for consumption by individuals afflicted with celiac disease, and its proteins can be used as a supplement in gluten-free foods. However, utilization of sorghum in human foods is limited by the poor digestibility and lack of functionality of its proteins, which result from their entrapment in protein bodies, tight association with starch, and high degree of cross-linking induced by cooking. The first part of this study presents an extensive review of current methods for concentration and isolation of sorghum proteins, which are laboratory-scale techniques used for protein characterization and have no potential for commercial scale-up. Furthermore, these methods typically use non-food grade reagents and do not improve protein digestibility and functionality. In the second part, a novel extrusion-enzyme liquefaction (EEL) process was used to produce sorghum protein concentrates to overcome the aforementioned limitations. EEL involves extrusion pre-treatment of sorghum flour and starch liquefaction with a thermostable α-amylase, followed by enzyme inactivation, protein separation and drying. To demonstrate the concept, a laboratory-scale EEL process was used to produce concentrates with higher protein content (PC; 80% db) and digestibility (D; 74%) than those made by batch liquefaction. The optimum conditions for producing concentrates with both high PC and D were 32% wb in-barrel moisture content and 2.5% α-amylase added after extrusion. Using these conditions, EEL was scaled-up to a pilot-scale process to produce sorghum protein concentrates with 72-80% db PC and 62-74% D, while the batch liquefied control had only 70% db PC and 57% D. Dynamic oscillatory measurements of dough (55% moisture) and batter (65% moisture) containing sorghum protein concentrates (5 and 10%) and potato starch were performed to evaluate protein functionality. At lower moisture, pure potato starch and dough containing 10% sorghum protein concentrate had similar elastic and viscous moduli. At higher moisture, potato starch was more stable and exhibited significantly higher moduli than the batters with protein concentrates. Sorghum protein concentrates can improve the quality of some gluten-free foods. EEL shows promise for commercial production of sorghum protein concentrates because of its high throughput and potential for delivering high protein content and digestibility.

Master of Science / Department of Agronomy / Tesfaye Tesso / Sorghum [Sorghum bicolor (L.) Moench] is listed as one of the potential feedstock sources for biofuel production. While sorghum grain can be fermented into ethanol in a similar way as maize, the greatest potential of the crop is based on its massive biomass and sugar rich juices. Thus development of the crop as alternative energy source requires improvement of these traits. The objectives of this study were (1) to determine the mode of inheritance of traits related to ethanol production and identify suitable genetic sources for use in breeding programs, and (2) to evaluate the potential of low lignin mutations for biomass feedstock production and assess biotic stress risks associated with deployment of the mutations. The study consisted of three related experiments: (i) estimating the combining ability of selected sweet and high biomass sorghum genotypes for biofuel traits and resistance to stalk lodging, (ii) determine the impact of brown mid-rib mutations on biofuel production and their reaction to infection by Macrophomina phaseolina and Fusarium thapsinum, and (iii) assess the reaction of low lignin mutants to green bug feeding. In the first experiment six sorghum genotypes of variable characteristics (PI193073, PI257602, PI185672, PI195754, SC382 and SC373) were crossed to three standard seed parent lines ATx3042, ATx623 and ATx399. The resulting hybrids and the parents were evaluated at four locations, three replications during 2009 and 2010 seasons. Data were collected on phenology, plant height, juice yield, °brix score and biomass production. In the second experiment, two brown mid-rib mutations (bmr6 and bmr12) and their normal versions were studied in four forage sorghum backgrounds (Atlas, Early Hegari, Kansas Collier and Rox Orange). The experiment was planted in four replications and at 14 d after flowering five plants in a plot were artificially infected with F. thapsinum and another five with M. phaseolina. The plants were harvested and rated for disease severity (lesion length and nodes crossed). Another five normal plants in each plot were harvested and used to determine biofuel traits (juice yield, ºbrix score and biomass). In the third experiment, a subset of entries evaluated in experiment II and three tolerant and susceptible checks were tested for greenbug feeding damage. Biotype K greenbug colony was inoculated to each genotype using double sticky foam cages. Feeding damage was assessed as percent chlorophyll loss using SPAD meter. There was significant general combining ability (GCA) effect among the male entries for juice yield, stem obrix and biomass production indicating that these traits are controlled by additive genes. Lines PI257602 and PI185672 in particular, had the highest GCA for all the traits and should serve as excellent breeding materials. There was no significant difference among the bmr mutants and between the bmr and normal genotypes for both stalk rot and greenbug damage. In conclusion, juice yield, °brix and biomass are largely controlled by additive genes and hence are amenable to genetic manipulation. The bmr mutations despite their impact on lignin content do not increase risk of attack by stalk rot pathogens and greenbugs and thus can be deployed for biofuel production without incurring losses to these factors.

Master of Science / Department of Agricultural Economics / Timothy J. Dalton / Millet and sorghum are major crops in Niger, West Africa. Improving the productivity of millet and sorghum is important to fight against poverty and malnutrition in this country. This study contributes to this objective by conducting efficiency level of millet, sorghum farmers, and the factors that influence efficiency. To reach this goal I applied a stochastic parametric frontier analysis using a cross-sectional data set collected by The Living Standards Measurement Study (LSMS) in 2011. I obtained 216 observations of plots that plant millet and 364 observations of plots that plant sorghum from 2011 to 2012 over the country. I employed Cobb–Douglas and Translog functional forms along with the half normal error distribution to estimate the production frontier. I also conducted a statistical test to choose the most appropriate functional form that fits the data for different crops. It was found that the mean technical efficiency of millet farmers is 38.44 percentage and sorghum farmers is 58.22 percentage. Lastly, I analyzed the correlates of technical inefficiency, I employed two-step approach. I found that the inefficiency of farmers is related to managerial factors such as education level or farming method.

Doctor of Philosophy / Department of Grain Science and Industry / Yong-Cheng Shi and Jeff D. Wilson / Sorghum (Sorghum bicolor [L.] Moench) is the fifth most important cereal grain grown in the world. Sorghum is an important cereal crop for both animal feed and biofuel production in the United States. The genetic, environmental, and agronomic management influences on sorghum starch and protein chemistry and functionality were evaluated. A method was developed to determine amylose content in cereal starches that achieved the same level of accuracy and precision as traditional methods, but had the capability of analyzing 50 samples per day or approximately a 10-fold increase in throughput. The effect of kernel maturity on sorghum starch properties was conducted by collecting grain from two hybrids at various stages throughout kernel development. The samples ranged from 16.3% amylose in 10 days after anthesis (DAA) to 23.3% amylose in 35 DAA. Starch thermal properties were also altered due to DAA, most notably the ΔH was 16.1 J/g at 14 DAA and 9.45 J/g at 56 DAA. In a separate study using the same developmental samples the protein and starch digestibility was analyzed. The kernel maturity had a notable effect on digestibility with the maximum digestibility occurring at 17 DAA with 82.44% digestible protein. In another study a diverse set of 19 sorghums was grown in three locations in Kansas to evaluate the genetic, location, and genetic x location effect on grain quality attributes. The physical and chemical properties of the sorghums were greatly affected by the genotype, environment, and the GxE interaction. Protein content ranged from 11.09% to 15.17% and digestibility ranged from 45.58% to 62.05% due to genotype. The final study investigates the role of agronomic management on sorghum grain quality. A sorghum hybrid was grown on plots with varying nitrogen fertilization rates and cover cropping systems that are currently used by Kansas producers. Grain attributes such as hardness and size were variable due to the treatments but negative impacts to protein digestibility were not seen due to cropping system. Sorghum grain quality is affected by many variables and a better understanding of the variables will lead to a higher quality product.

Doctor of Philosophy / Department of Agronomy / Kraig L. Roozeboom / Previous research has revealed that winter wheat (Triticum aestivum L.) yields are often reduced following grain sorghum [Sorghum bicolor (L.) Moench] compared to wheat after other summer crops. The objectives of the study were to: (a) evaluate grain sorghum residue management strategies to improve the performance of a following winter wheat crop in no-till systems; (b) determine grain sorghum hybrid characteristics that facilitate planting wheat following grain sorghum, and identify winter wheat cultivars that are suitable for planting after grain sorghum; (c) evaluate effect of environment, sampling time, and grain sorghum hybrid plant pigmentation on phenolic acid concentration in sorghum residues. Experiments were conducted in environments suitable for planting winter wheat following a summer crop. Treatments for objective one were: glyphosate (pre-harvest application, post-harvest, none), residue (removed, chopped, left standing), and nitrogen (34 kg ha⁻¹ applied to residue, none). Treatments for objective two and three were grain sorghum hybrids representing three maturities (early, medium, medium-late) and two plant pigmentations (red, tan), wheat cultivars occupying significant planted acreage and having favorable performance within the region. Wheat yields increased in two environments by 217 and 630 kg ha⁻¹ when glyphosate was applied to the sorghum pre-harvest. Residue chopping or removal either had no effect or a negative effect on wheat yields compared to residue left standing. Nitrogen applied to the sorghum residue increased wheat yields in only one environment. Grain sorghum hybrid characteristics did not influence winter wheat yields in any environment, but winter wheat cultivar did influence grain yields of the winter wheat in three of the four environments. Breakdown of phenolic acids depended on environment. Results for these studies indicate that wheat yield after a grain sorghum crop can be maximized by planting a red-pigmented sorghum hybrid of an early or medium maturity, desiccating the sorghum crop with pre-harvest glyphosate if it can be applied to the sorghum roughly 45 to 50 days before a frost, and with a wheat cultivar that is well suited to no-till planting.

Digitized by Kansas Correctional Industries

LD2668 .T4 1947 D68 / Master of Science