Industry demand for local sources of grain for animal feed has increased sorghum production in the mid-Atlantic region of the U.S. Sorghum anthracnose (causal agent Colletotrichum sublineola) and the grain mold complex, which includes mycotoxin-producing Fusarium spp., limit the yield and quality of grain sorghum in humid climates worldwide. A majority of U.S. grain sorghum production is in arid regions, and management strategies have not been developed for the mid-Atlantic U.S. where warm, wet conditions favor disease. The specific objectives of this research were to: (1) determine the effectiveness of fungicides and their application timing for the management of sorghum foliar anthracnose, (2) compare five grain sorghum hybrids for their susceptibility to foliar anthracnose, grain mold and mycotoxin contamination under field conditions, (3) integrate host resistance and fungicide application to manage anthracnose and grain mold, and (4) identify Fusarium spp. associated with grain mold and mycotoxin contamination of sorghum in the mid-Atlantic U.S. For Objective 1, it was determined that a single application of pyraclostrobin-containing fungicide no later than flowering reduced anthrancose, protected yield and maximized farm income. Objective 2 focused on sorghum hybrid selection as a disease management tactic, and it was determined that hybrids with high yield potential and moderate disease resistance should be selected for mid-Atlantic sorghum production in order to maximize grain yield and quality while minimizing the need for fungicide inputs. Objective 3 focused on integrated management and demonstrated that under moderate disease pressure, a high-yielding susceptible hybrid required a single application of pyraclostrobin-based fungicide to minimize fungal diseases and maintain acceptable yields, whereas under high disease pressure it was necessary to integrate hybrid resistance and judicous applications of fungicides. The aim of Objective 4 was to characterize potential causal agents of mycotoxin contamination in mid-Atlantic sorghum, and thirteen phylogenetically distinct Fusarium species (F. lacertarum, F. graminearum. F. armeniacum, F. proliferatum, F. fujikuroi, F. verticillioides, F. thapsinum and several in Fusarium incarnatum-equiseti species complex) were found to be associated with grain mold and fumonisin and/or deoxynivalenol contamination of sorghum grain. This work has provided insights into the impacts of fungal diseases on grain sorghum yield and quality in the mid-Atlantic and has aided in development of best management practices for the region. / Doctor of Philosophy / Sorghum is grown in tropics, sub-tropics and semi-arid region worldwide for food, feed, forage and fuel. Sorghum acreage in the mid-Atlantic is increasing due the demand for locally grown grain by poultry and swine industries. During the growing season, warm and humid conditions are common in the southeastern and mid-Atlantic states favoring fungal diseases development that reduce the grain yield and quality. Anthracnose and grain mold, which includes toxic mycotoxin-producing Fusarium species, are the two major constraints in sorghum production in the region. However, management alternatives have not been developed. The main goal of this research was to develop management strategies to protect yield and maximize farm profitability by controlling anthracnose and grain mold of sorghum using chemicals and/or host resistance. The specific objectives were to: (1) determine the effectiveness of fungicides and their application timing for the management of sorghum foliar anthracnose, (2) compare grain sorghum hybrids for their susceptibility to foliar anthracnose, grain mold and mycotoxin contamination under field conditions, (3) assess the value of integrating host resistance and judicious use of fungicides to manage sorghum anthracnose and grain mold, and (4) identify Fusarium spp. associated with grain mold and mycotoxin contamination of sorghum in the mid-Atlantic U.S. Results from this research indicate that a single application of pyraclostrobin-containing fungicides no later than flowering reduces anthrancose, protects yield, and increases farm income. Sorghum hybrids varied in susceptibility to anthrancnose and grain mold, and planting a moderately resistant hybrid and applying a fungicide under high disease risk conditions provided the greatest return on investment. Both fumonisin and deoxynivalenol were frequently detected from sorghum grain, and mycotoxin contamination was associated with 13 different Fusarium species from three distinct species complexes. Based on the results of this work, best management practices for minimizing sorghum disease losses were developed for the mid-Atlantic region.

Master of Science / Entomology / Brian McCornack / Several lepidopteran species infest developing panicles. Larval identification is challenging and time intensive, so current recommendations are often simplified by treating all larvae equally across species. Consequently, the yield-loss model developed for corn earworm (Helicoverpa zea) by Buckley and Burkhardt (1962) has been the foundation for management recommendations in modern sorghum Integrated Pest Management (IPM) programs for the last 49 years. Additionally, although pest populations primarily include both fall armyworm (Spodoptera frugiperda) and corn earworm, only a single species damage estimate is used in economic threshold (ET) and economic injury level (EIL) calculations despite multi-species infestations. This research demonstrates both the validation of current management recommendations for corn earworm and the verification of previously assumed damage potentials for fall armyworm feeding in developing sorghum panicles. These results have important implications for sorghum producers faced with making a management decision for multi-species infestations.

The diploma thesis focuses on comparison of biomass production, dry matter of grain sorghum and sweet content. Four hybrids of sweet sorghum and one hybrid of grain sorghum were chosen for the evaluation. A small-parcel experiment with a line spacing of 0.75 meters was established for the comparison. The experiment was going on for two years. Two years of monitoring showed the differences in yield on biomass and dry matter of individual hybrids. A great potential of biomass and dry matter production in convenient weather condition and the ability of the yield produc-tion in dry and hot conditions by sweet hybrids emerge from the two years results. A grain hybrid yielded a small amount of both biomass and dry matter in both years.

Master of Science / Department of Agronomy / Robert M. Aiken / Mary B. Kirkham / Transpiration efficiency (TE) is defined as total biomass produced per unit of water transpired. Improvement of TE means maximizing crop production per unit of water used. The objectives of the study were to examine, at the leaf level and the whole plant level, the variation in TE for sorghum [Sorghum bicolor (L.) Moench] accessions, previously screened for TE and to test physiological mechanisms that may account for differences in TE. Three field studies and two mini-lysimeter studies (one done in pots under greenhouse conditions and one done in pots in the field) were conducted with eight accessions. Instantaneous measurements of assimilation (A), stomatal conductance (gs), and transpiration by gas exchange provided measures of the transpiration efficiency at the leaf level. Growth observations and soil water balance in field plots quantified components of whole-plant TE. Growth and development measurements showed significant difference, explaining the existence of photoperiod sensitivity among the sorghum genotypes. Assimilation (A), stomatal conductance (gs), and maximum quantum efficiency of photosystem II (Fv/Fm) were consistently greater for accession PI533946 (from India) and greater for accession PI295121 (from Australia) in both field and the field-pot studies (p<0.05). Internal carbon dioxide (Ci), an indicator of intrinsic transpiration efficiency, differed among lines under field conditions (p<0.05). Leaf relative water content (RWC), measured in the greenhouse, and did not differ among the eight accessions. No consistent differences in biomass and water use were detected among lines under field conditions. In conclusion, developing reliable selection indices for TE will require a greater understanding of whole-plant physiological processes to utilize the differences in TE observed at the leaf level.

O etanol está consolidado como combustível para movimentação de veículos leves no Brasil e, nos últimos 40 anos, apenas a cultura de cana-de-açúcar tem sido explorada comercialmente para a produção deste combustível. Por outro lado, o desenvolvimento agrícola vem proporcionando safras recordes de grãos nas últimas décadas. A produção de milho se destaca pelo aumento da produtividade, podendo ser semeado como cultura principal ou como cultura de inverno em rotação com a soja. O sorgo, por sua vez, pode atuar como um substituto do milho, apresentando maior rusticidade e tolerância à seca. Dada essa conjuntura, usinas de etanol do Mato Grosso se associaram a produtores de milho e sorgo para incluir novas matéria-primas no processo de produção de combustíveis, compartilhando uma mesma unidade industrial, denominada Usina Integrada ou Usina Flex. No contexto atual, o desenvolvimento de novas tecnologias e setores produtivos exige a consideração de suas potenciais implicações energéticas e ambientais. A Avaliação de Ciclo de Vida (ACV) é uma ferramenta da gestão ambiental usada para avaliar impactos ambientais potenciais associados a produtos, processos e serviço. Sua principal característica é se prestar a essa avaliação de forma sistêmica, levando em conta todas as etapas do seu ciclo de vida. O objetivo deste trabalho foi avaliar e comparar os desempenhos ambiental e energético da produção de etanol a partir dos ativos agrícolas cana-de-açúcar, milho e sorgo, no contexto de usina autônoma integrada, segundo a abordagem do ciclo de vida. Para tanto, estudos de ACV foram conduzidos para cada um dos três produtos, seguindo as diretrizes das normas ABNT NBR ISO 14.040:2009 e ABNT NBR ISO 14.044:2009. Para a análise ambiental aplicou-se o método de Avaliação de Impacto do Ciclo de Vida (AICV) ReCiPe midpoint e, para a análise energética, o método Demanda de Energia Cumulativa foi utilizado, seguido pelo cálculo dos Índices de Retorno Energético sobre o Investimento (EROI) para cada combustível. A unidade funcional dos estudos foi 1 m³ de etanol hidratado e o sistema de produto incluiu a produção de insumos, produção da matéria-prima agrícola, produção de etanol, cogeração e etapas de transporte. Os resultados da análise ambiental demonstraram que o etanol de cana-de-açúcar apresenta melhor desempenho do que o etanol de milho e de sorgo em um número maior de categorias de impacto. As análises energéticas demonstraram que o uso de cavaco de madeira na etapa de cogeração dos processos de produção de etanol de milho e sorgo traduziu-se em ganhos energéticos, mas o etanol de cana-de-açúcar ainda apresenta um desempenho melhor por utilizar o bagaço para cogeração. Em termos de EROI, o etanol de cana-de-açúcar disponibilizou 9,77 unidades de energia para cada unidade consumida, o etanol de milho disponibilizou 2,68 e o etanol de sorgo disponibilizou 3,10. / Ethanol is consolidated as fuel to drive light vehicles in Brazil, but for the past 40 years, only the cultivation of sugarcane has been commercially exploited for the production of this fuel. On the other hand, agricultural development has provided high yields of grain in recent decades. Corn production is distinguished by increased productivity, and can be sown as main crop or as a winter crop in rotation with soybeans. Sorghum, in turn, has a higher roughness and tolerance to drought and can act as a substitute for corn. Given this situation, ethanol plants in Mato Grosso were associated with corn and sorghum producers to include new raw materials in the fuel production process, sharing the same plant, called Integrated Plant or Plant Flex. However, the development of new technology and production sectors requires consideration of its potential energy and environmental implications. The Life Cycle Assessment (LCA) is management tool used to evaluate potential environmental impacts associated with products, processes and services. Its main feature is to provide such an assessment in a systematic way, taking into account all stages of their life cycle. The objective of this study was to evaluate and compare the environmental and energy performance of ethanol production from sugarcane, corn and sorghum in the context of integrated autonomous plant, according to the life cycle approach. For that, LCA studies were conducted for each of the three products, following the guidelines of the standards ISO 14040: 2009 and ISO 14044: 2009. For environmental analysis the method of Life Cycle Impact Assessment (LCIA) Recipe midpoint was applied and for energy analysis Cumulative Energy Demand method was used, followed by the estimate of the Energy Return On Investment (EROI) for each fuel. The functional unit of the studies was 1 m³ of hydrous ethanol and the product system includes the production inputs, production of agricultural raw material, production of ethanol, cogeneration and transport stages. The results of the environmental analysis showed that the ethanol sugarcane performs better than the ethanol maize and sorghum in a greater number of impact categories. Energy analyzes have shown that the use of wood chips in cogeneration stage of corn ethanol production processes and sorghum has resulted in energy savings, but the ethanol sugarcane still performs better by using bagasse for cogeneration. In terms of EROI, the sugarcane ethanol provided 9.77 units of energy for every unit consumed, corn ethanol provided 2.68 and sorghum ethanol provided 3.10.

O etanol está consolidado como combustível para movimentação de veículos leves no Brasil e, nos últimos 40 anos, apenas a cultura de cana-de-açúcar tem sido explorada comercialmente para a produção deste combustível. Por outro lado, o desenvolvimento agrícola vem proporcionando safras recordes de grãos nas últimas décadas. A produção de milho se destaca pelo aumento da produtividade, podendo ser semeado como cultura principal ou como cultura de inverno em rotação com a soja. O sorgo, por sua vez, pode atuar como um substituto do milho, apresentando maior rusticidade e tolerância à seca. Dada essa conjuntura, usinas de etanol do Mato Grosso se associaram a produtores de milho e sorgo para incluir novas matéria-primas no processo de produção de combustíveis, compartilhando uma mesma unidade industrial, denominada Usina Integrada ou Usina Flex. No contexto atual, o desenvolvimento de novas tecnologias e setores produtivos exige a consideração de suas potenciais implicações energéticas e ambientais. A Avaliação de Ciclo de Vida (ACV) é uma ferramenta da gestão ambiental usada para avaliar impactos ambientais potenciais associados a produtos, processos e serviço. Sua principal característica é se prestar a essa avaliação de forma sistêmica, levando em conta todas as etapas do seu ciclo de vida. O objetivo deste trabalho foi avaliar e comparar os desempenhos ambiental e energético da produção de etanol a partir dos ativos agrícolas cana-de-açúcar, milho e sorgo, no contexto de usina autônoma integrada, segundo a abordagem do ciclo de vida. Para tanto, estudos de ACV foram conduzidos para cada um dos três produtos, seguindo as diretrizes das normas ABNT NBR ISO 14.040:2009 e ABNT NBR ISO 14.044:2009. Para a análise ambiental aplicou-se o método de Avaliação de Impacto do Ciclo de Vida (AICV) ReCiPe midpoint e, para a análise energética, o método Demanda de Energia Cumulativa foi utilizado, seguido pelo cálculo dos Índices de Retorno Energético sobre o Investimento (EROI) para cada combustível. A unidade funcional dos estudos foi 1 m³ de etanol hidratado e o sistema de produto incluiu a produção de insumos, produção da matéria-prima agrícola, produção de etanol, cogeração e etapas de transporte. Os resultados da análise ambiental demonstraram que o etanol de cana-de-açúcar apresenta melhor desempenho do que o etanol de milho e de sorgo em um número maior de categorias de impacto. As análises energéticas demonstraram que o uso de cavaco de madeira na etapa de cogeração dos processos de produção de etanol de milho e sorgo traduziu-se em ganhos energéticos, mas o etanol de cana-de-açúcar ainda apresenta um desempenho melhor por utilizar o bagaço para cogeração. Em termos de EROI, o etanol de cana-de-açúcar disponibilizou 9,77 unidades de energia para cada unidade consumida, o etanol de milho disponibilizou 2,68 e o etanol de sorgo disponibilizou 3,10. / Ethanol is consolidated as fuel to drive light vehicles in Brazil, but for the past 40 years, only the cultivation of sugarcane has been commercially exploited for the production of this fuel. On the other hand, agricultural development has provided high yields of grain in recent decades. Corn production is distinguished by increased productivity, and can be sown as main crop or as a winter crop in rotation with soybeans. Sorghum, in turn, has a higher roughness and tolerance to drought and can act as a substitute for corn. Given this situation, ethanol plants in Mato Grosso were associated with corn and sorghum producers to include new raw materials in the fuel production process, sharing the same plant, called Integrated Plant or Plant Flex. However, the development of new technology and production sectors requires consideration of its potential energy and environmental implications. The Life Cycle Assessment (LCA) is management tool used to evaluate potential environmental impacts associated with products, processes and services. Its main feature is to provide such an assessment in a systematic way, taking into account all stages of their life cycle. The objective of this study was to evaluate and compare the environmental and energy performance of ethanol production from sugarcane, corn and sorghum in the context of integrated autonomous plant, according to the life cycle approach. For that, LCA studies were conducted for each of the three products, following the guidelines of the standards ISO 14040: 2009 and ISO 14044: 2009. For environmental analysis the method of Life Cycle Impact Assessment (LCIA) Recipe midpoint was applied and for energy analysis Cumulative Energy Demand method was used, followed by the estimate of the Energy Return On Investment (EROI) for each fuel. The functional unit of the studies was 1 m³ of hydrous ethanol and the product system includes the production inputs, production of agricultural raw material, production of ethanol, cogeneration and transport stages. The results of the environmental analysis showed that the ethanol sugarcane performs better than the ethanol maize and sorghum in a greater number of impact categories. Energy analyzes have shown that the use of wood chips in cogeneration stage of corn ethanol production processes and sorghum has resulted in energy savings, but the ethanol sugarcane still performs better by using bagasse for cogeneration. In terms of EROI, the sugarcane ethanol provided 9.77 units of energy for every unit consumed, corn ethanol provided 2.68 and sorghum ethanol provided 3.10.

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 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.