Energy sorrel (Rumex patientia L. x Rumex tianschanicus A. Los.) is a plant with a high yield of above-ground biomass. Because of this, it is grown as energy crop, but in Ukraine it is also important forage crop. Mycobiota has not been examined, even though energy sorrel is grown in the Czech Republic experimentally since 1992 (in agricultural operations since 2001). The aims of this thesis were: to determine the composition of mycobiota of healthy plants and of mycobiota associated with leaf and stem spots, to verify whether fungi isolated from spots can cause these spots and if previously isolated fungus Phomopsis sp. can cause spots. Samples were colected from 4 sites in Czech republic, in three samplings during the vegetation season. Endophytes were isolated from root, stem and leaf. Fungi asociated with spots were isolated from stem and leaf. Fungi were cultivated on 2% malt extract agar and then morphologically determined. From representative strains were isolated DNA and sequences of the ITS region were compared with the GenBank databases, this verified the morphological determination and the sterile species were determined. The most common endophytes were Clonostachys rosea f. rosea, Cladosporium cladosporioides, Rhizopus arrhizus var. arrhizus, Alternaria alternata a Acremonium strictum...

Energy sorrel (Rumex patientia L. x Rumex tianschanicus A. Los.) is a plant with a high yield of above-ground biomass. Because of this, it is grown as energy crop, but in Ukraine it is also important forage crop. Mycobiota has not been examined, even though energy sorrel is grown in the Czech Republic experimentally since 1992 (in agricultural operations since 2001). The aims of this thesis were: to determine the composition of mycobiota of healthy plants and of mycobiota associated with leaf and stem spots, to verify whether fungi isolated from spots can cause these spots and if previously isolated fungus Phomopsis sp. can cause spots. Fungi were cultivated on 2% malt extract agar and then morphologically determined. From representative strains were isolated DNA and sequences of the ITS region were compared with the GenBank databases, this verified the morphological determination and the sterile species were determined. In total 24 morphotypes of endophytic fungi were cultivated from healthy plants. The most common species were: Clonostachys rosea f. rosea, Cladosporium cladosporioides, Rhizopus arrhizus var. arrhizus, Alternaria alternata and Acremonium strictum. From the spots were isolated in total 29 morphotypes, the dominant species were: A. strictum, Aureobasidium pullulans, C....

Doctor of Philosophy / Department of Agronomy / Charles W. Rice / Nitrogen is critical for plant growth and is a major cost of inputs in production agriculture. Too much nitrogen (N) is also an environmental concern. Agricultural soils account for 85% of anthropogenic N₂O which is a major greenhouse gas. Management strategies for N fertilization and tillage are necessary for enhancing N use efficiency and reducing negative impacts of N to the environment. The different management practices induce changes in substrate availability for microbial activity that may result in increasing or reducing net N₂O emitted from soils. The objectives of this research were to (1) integrate results from field studies to evaluate the effect of different management strategies on N₂O emissions using a meta-analysis, (2) quantify N₂O-N emissions under no-tillage (NT) and tilled (T) agricultural systems and the effect of different N source and placements, (3) perform sensitivity analysis, calibration and validation of the Denitrification Decomposition (DNDC) model for N₂O emissions, and (4) analyze future scenarios of precipitation and temperature to evaluate the potential effects of climate change on N₂O emissions from agro-ecosystems in Kansas. Based on the meta-analysis there was no significant effect of broadcast and banded N placement. Synthetic N fertilizer usually had higher N₂O emission than organic N fertilizer. Crops with high N inputs as well as clay soils had higher N₂O fluxes. No-till and conventional till did not have significant differences regarding N₂O emissions. In the field study, N₂O-N emissions were not significantly different between tillage systems and N source. The banded N application generally had higher emissions than broadcasted N. Slow release N fertilizer as well as split N applications reduced N₂O flux without affecting yield. Simulations of N₂O emissions were more sensitive to changes in soil parameters such as pH, soil organic carbon (SOC), field capacity (FIELD) and bulk density (BD), with pH and SOC as the most sensitive parameters. The N₂O simulations performed using Denitrification Decomposition model on till (Urea) had higher model efficiency followed by no-till (compost), no-till (urea) and till (compost). At the regional level, changes in climate (precipitation and temperature) increased N₂O emission from agricultural soils in Kansas. The conversion from T to NT reduced N₂O emissions in crops under present conditions as well as under future climatic conditions.

Master of Science / Department of Agricultural Economics / Vincent R. Amanor-Boadu / Women represent approximately 50 percent of the active labor force in Sub-Saharan Africa. Even though women are involved in a variety of agricultural activities, they have limited access to resources and have restricted decision-making power compared to their male counterparts (FAO, 2011). These limitations and restrictions are likely to have a significant effect on women’s performance levels compared to men. The present research measures the gender-based performance differences, identifies factors that influence the financial performance levels, and factors contributing to generate disparities between male and female smallholders performance in northern Ghana. Data used in this study are from the Agriculture Production Survey (APS) focusing on the 2013-2014 cropping season. The study uses the Oaxaca-Blinder decomposition method to measure and decompose the gender performance gap in two parts: endowment effect and structural effect. Gross margin is used to measure farmer’s financial performance. The endowment effect is attributed to differences in the explanatory variables, and the structural effect is associated with differences in returns of the explanatory variables. Results from the study indicate there is a gender gap between male and female smallholder farmers with male farmers outperforming females by 46 percent. Land area had the largest significant impact on the explained part of the gender gap, followed by tractor service. The endowment effect portion of the decomposition models is accounted for 35 percent of the gender gap, and the remaining 65 percent is associated with the structural effect. The larger structural effect part suggests that developing programs to establish equality among male and female smallholder producers in terms of access to resources will not close the gender gap. Additionally, factors contributing positively overall to gross margin of smallholder farmers were land area, and tractor services and crops produced. Based on the results of this research, policymakers and agribusiness stakeholders may look to reduce the gender gap existing between smallholder farmers in northern Ghana by empowering women by providing them access to land area and tractor services. Further research into factors affecting the gender gap in financial performance in agricultural activities is warranted.

Då Sverige redan nått flera av de energi- och klimatpolitiska målen kan målet om att skapa ett fossilfritt samhälle stå som ytterligare drivkraft för att fortsätta utvecklingen av de hållbara bränslena. Bidrag finns att få för att anlägga våtmarker, minska klimatpåverkan, förbättra naturmiljön och för utvecklandet av ny teknik samt bygga upp anläggningar för biobränsleproduktion. Trots detta har odling av våtmarksgrödor för energiutvinning ännu inte etablerats på energimarknaden. Denna studie är en del i kartläggningen av vad som kan komma att driva utvecklingen av våtmarker som källa till bioenergi framåt, och vilka delar som saknas i det arbetet. Efter intervjuer med intresserade och kunniga aktörer inom ämnet presenteras här de drivkrafter och hinder som påverkar denna utveckling. Drivkrafterna grundar sig i viljan att komma bort från fossila bränslen, att minska utsläppen av näringsämnen samt ge utrymme för biologisk mångfald, samtidigt som åtgärderna kan göra nytta för samhället och hjälpa till att nå klimat- och miljömålen. De största hindren utgörs av att speciella maskiner kan behövas för behandling av våtmarksgrödorna där terrängen är känslig och att mycket stora ytor skulle behövas för att öka lönsamheten. De ekonomiska stöd som finns att tillgå täcker inte heller alla nödvändiga steg i produktionsledet. Eftersom priserna på el och fossila bränslen är låga finns ännu ingen etablerad marknad för denna typ av energikälla och produktionen leder därför inte till någon större förtjänst. Biobränsleproducenter har även svårt att på ett tillräckligt effektivt sätt utvinna energin från grödorna. Detta gör att efterfrågan på energigrödor från våtmarker idag är mycket låg. Trots detta kan våtmarker bidra med en rad viktiga ekosystemtjänster i samband med produktion av energigrödor. Det rekommenderas därför att ett sådant system präglas av förvaltningsfilosofin mångbruk, där en naturresurs syfte är att nyttjas för flera ändamål samtidigt. Detta multifunktionella synsätt kan hjälpa till att öka våtmarkernas roll i uppfyllandet av flera av de nationella klimat- och miljömålen, om dess ekosystemtjänster vägs in tydligare i kalkylerna vid energiproduktion. / Sweden have already reached several of their goals for energy consumption, but the overall goal to become a fossil free society can still be seen as a driving force to keep developing renewable fuels. There is financial support for wetland construction, reduce impact on the climate, improve the natural environment, for developing new techniques and for biomass fuel plants. Still, cultivation of wetland crops for energy extraction are not yet well established on the energy market. After interviews with actors interested and knowledgeable in this field, this study presents driving forces and barriers affecting the development of this energy source. Driving forces comes from the ambition to move away from fossil fuels, decrease emissions of nutrients, make room for biodiversity, and provide services for the society while helping to reach climate and environmental goals. The barriers affecting this development is that special machines might be needed for handling of the crops and also to harvest the sensitive wetlands while large areas would be needed to increase profitability. The financial support available is not enough to cover the costs for production. Also, the prices on electricity and fossil fuels are low, which lowers the profitability for this type of energy source. Bioenergy producers have not yet found an effective way to extract energy from the crops. All of this makes the demand for energy crops from wetlands small. Despite this, wetlands provide several important ecosystem services and it is therefore recommended to use the management philosophy of multiple-use. With a multifunctional view of wetlands, the value of its ecosystem services can be added to the calculations of energy production and increase its role in reaching several national climate and environmental goals.

thesis submitted to the Faculty of Science in fulfilment of the requirements for the degree of Doctor of Philosophy. March 17, 2015. / A two-level facility location problem (FLP) arose in the transport network of maize crop in Tanzania has been studied. The three layers, namely, production centers (PCs), distribution centers (DCs) and customer points (CPs) are considered in the two-level FLP. The stochastic e ect on the two-level FLP due to rainfall in the network links, between the DCs and CPs, has been studied. The ow of maize crop from PCs to CPs through DCs is designed at a minimum cost under deterministic and stochastic scenarios. The three decisions made simultaneously are: to determine the locations of DCs (including number of DCs), allocation of CPs to the selected DCs, allocation of selected DCs to PCs, and to determine the amount of maize crop transported from PCs to DCs and then from DCs to CPs. We have modelled the problem and generate results by optimizing the model with respect to optimal location-allocation strategies. We have considered two networks, the existing network and an extended network. In the existing network there are four PCs, ve DCs and ninety three CPs. In the extended network three additional DCs are considered. For the modelling purpose we have used the rainfall data from 2007 - 2010 in each week for 17 weeks. The optimized results for the existing network have shown improvements in cost saving compared to the manually operated existing network. In the extended network, the results have shown much more e cient and cost saving distribution system compared to the results of the existing network.

Spodoptera frugiperda is one of the main insect pests of the New World, and causes extensive damage to economically important crops such as cotton and corn. One of the most common control strategies is the use of Bt plants; however, their intense and indiscriminate use has led to the evolution of resistance in some populations. The establishment of a refuge can be a viable option to delay this process. Refuges consist of areas where non-Bt crops are planted, in order to provide susceptible insects to the population. In this study, I initially developed a model to describe the evolution of resistance of fall armyworm populations in different refuge configurations (seed mixture, blocks, and strips) and sizes (20% - 50%), considering the larval movement. I demonstrated that with a seed mixture, in most cases, the higher the rate of larval movement, the higher the proportion of resistant insects in the population, regardless of the type of resistance tested; meanwhile, strip configurations showed the opposite trend. In the second part of this study, I obtained data to validate the proposed model. The development of the fall armyworm on corn leaves was determined at five constant temperatures ranging from 14°C to 30°C. These data were also used to estimate the number of generations of fall armyworms at 42 locations in the state of Florida, from 2006 to 2016, which were interpolated and represented on maps, using GIS (Geographic Information System). I observed that counties farther south had the highest numbers of generations, and that fall armyworms should be able to overwinter as far north as ~29°N. Using the data obtained in the experiment, a new model was proposed, covering a wider range of conditions and allowing the user to define the crop area, the thermal requirements of the population studied, the viability and oviposition functions, the migration rate, the rate of larval movement and the frequency of alleles for resistance. The model was verified with monitoring data collected in a crop area in Florida from 2012 - 2015, only 70 km from the area that provided the population for the experiment. I also used the model to estimate the number of adults for 2016 and for two hypothetical situations that considered possible scenarios involving global warming (mean temperatures in 2016 + 1°C and + 2°C). The model succeeded in fitting the monitoring data, and indicated that the simulated increases in mean temperature could produce outbreaks nearly twice as large as the levels of fall armyworm estimated for 2016. The model can be used to estimate the population dynamics of S. frugiperda in a particular area, according to the crop composition and disposal, to investigate the effects of temperature changes on the levels of fall armyworm populations, to define appropriate refuge areas in order to manage the evolution of insect resistance, and to define the best periods for plantation and harvesting during the year to reduce pest populations, among others. / Spodoptera frugiperda é um dos principais insetos-praga do hemisfério ocidental, causando diversos danos a cultivos de interesse econômico, como milho e algodão. Uma das estratégias mais comuns de controle é o uso de plantas Bt, contudo sua aplicação intensa e indiscriminada levou à evolução de resistência em algumas populações. O estabelecimento de refúgio pode representar uma opção viável para atrasar esse processo. Refúgios são áreas nas quais cultivos não-Bt são plantados de forma a fornecerem insetos suscetíveis para a população. Neste estudo, eu desenvolvi inicialmente um modelo para descrever a evolução de resistência de populações de S. frugiperda em diferentes configurações de refúgio (mistura de sementes, blocos e faixas) e tamanhos (20 - 50%), considerando o movimento larval. Eu demonstrei que para a mistura de sementes, na maioria dos casos, maiores taxas de movimentação larval implicavam em maiores proporções de insetos resistentes na população, independente do tipo de resistência testada, enquanto áreas com configurações em faixas apresentaram tendência oposta. Na segunda parte deste trabalho, eu obtive dados para validar o modelo proposto. O desenvolvimento de S. frugiperda em folhas de milho foram determinadas em 5 temperaturas constantes variando de 14°C a 30°C. Estes dados também foram utilizados para estimar o número de gerações do inseto em 42 localizações no estado da Flórida de 2006 a 2016, que foram interpolados e representados em mapas, utilizando SIG (Sistema de Informações Geográficas). Eu observei que condados mais ao sul apresentaram maior número de gerações e que S. frugiperda é capaz de passar o inverno abaixo de latitudes ~29°N. Utilizando os dados obtidos no experimento, um novo modelo foi proposto, considerando um intervalo maior de condições e permitindo ao usuário definir a área de cultivo, as exigências térmicas da população estudada, as funções de oviposição e viabilidade, a taxa de migração, a taxa de movimentação larval e a frequência do alelo de resistência. O modelo foi verificado com dados de monitoramento de 2012 a 2015, coletados em uma área de cultivo localizada na Flórida, distante apenas 70 km da área que forneceu a população para o experimento laboratorial. Eu também utilizei o modelo para estimar o número de adultos para 2016 e para duas situações hipotéticas que consideraram possíveis cenários envolvendo o aquecimento global (médias de temperaturas de 2016 + 1°C e + 2°C). O modelo se ajustou aos dados de monitoramento com sucesso e indicou que os aumentos simulados na temperatura média poderiam produzir surtos quase duas vezes maiores que os níveis de S. frugiperda estimados para 2016. O modelo pode ser usado para estimar a dinâmica populacional de S. frugiperda em uma determinada área de acordo com a composição e disposição dos cultivos, investigar os efeitos das mudanças de temperatura nos níveis populacionais, definir áreas de refúgio apropriadas para o manejo da evolução de resistência, definir os melhores períodos para plantação e colheita durante o ano de forma a reduzir a população da praga, entre outros.

A planta daninha Amaranthus palmeri é nativa dos Estados Unidos, porém foi pela primeira vez relatada no Brasil no ano de 2015. Embora comprovadamente com resistência múltipla aos herbicidas inibidores da ALS e da EPSPS, até o momento não foram investigadas as bases moleculares da resistência. Além disso, por causa da recente introdução da planta daninha no país, alternativas de manejo com culturas tolerantes a herbicidas necessitam ser estudadas. Sendo assim, os objetivos desse trabalho são de caracterizar a espécie de planta daninha introduzida no país, identificar os mecanismos de resistência aos herbicidas inibidores da ALS e da EPSPS presentes no biótipo, e propor abordagens de manejo em ambientes dos novos eventos transgênicos resistentes a herbicidas. Um bioensaio utilizando marcadores genéticos foi desenvolvido para confirmar que a população coletada no estado do Mato Grosso (BR-R) é A. palmeri, e não A. tuberculatus, outra espécie dióica do gênero Amaranthus. Os resultados de experimentos de curvas de dose-resposta e acúmulo de chiquimato indicaram que a BR-R possui alto nível de resistência, com DL50 de 4.426 e 3.400 g glyphosate ha-1 no primeiro e segundo experimento, respectivamente, mais que o dobro da dose típicamente recomendada para o controle da espécie e, adicionalmente, observou se acúmulo mínimo de chiquimato a concentração de 1 mM nos tecidos das plantas tratadas com o herbicida. BR-R também foi resistente a herbicidas dos grupos químicos das sulfoniluréias e imidazolinonas. O mecanismo de resistência ao glyphosate encontrado nesta população foi a super expressão gência, através do aumento no número de cópias do gene da EPSPS no genoma da planta BR-R, entre 50 e 179 cópias adicionais. Além disso, duas substituições de aminoácidos foram observadas na sequência da ALS, W574L e S653N, conferindo resistência tanto a sulfoniluréias quanto a imidazolinonas. No experimento utilizandos os herbicidas correspondentes às culturas geneticamente modificadas com novos traits de tolerância a herbicidas observou se, de uma forma geral, que as associações de herbicidas apresentaram níveis de controle mais satisfatórios. Assim, esta pesquisa confirma a introdução de da espécie A. palmeri no Brasil, assim como a resistência múltipla aos herbicidas inibidores da EPSPS e da ALS. Seu manejo é mais eficaz através da associação de herbicidas, garantindo assim o uso racional das novas tecnologias de culturas geneticamente modificadas com tolerância a herbicidas. / Palmer Amaranth (Amaranthus palmeri) is a weed species native to the United States, but it was reported in Brazil for the first time in 2015. Despite this population being resistant to EPSPS and ALS inhibitors, the molecular basis of its multiple resistance is unknown up to date. Because of this species introduction to Brazil, alternatives of management with the new herbicide-tolerant crops technologies need to be studied. The objectives of this research are to characterize the weed species introduced to Brazil, identify the mechanisms conferring resistance to ALS and EPSPS inhibitors herbicides, and to propose management approaches in environments with the new genetically modified herbicide-tolerant crops. A genotyping bioassay using genetic markers was developed to confirm that the species collected in the state of Mato Grosso (BR-R) is indeed A. palmeri and not A. tuberculatus, another dioceous species in the Amaranthus genus. Dose-response experiments and shikimate accumulation bioassay data indicate high level of resistance, with LD50 of 4,426 and 3,400 g glyphosate ha-1 in the first and second experiments, respectively, higher than the double rate tipically recommended to control it, and minimal accumulation in BR-R with 1 mM of glyphosate in treated plants in the leaf disks assay. BR-R also was resistanto to sulfonilurea and imidazolinone herbicides. The mechanism conferring resistance to glyphosate identified in this population was gene amplification, with increased EPSPS copy number - between 50 and 179 more copies in BR-R. Besides, two target-site mutations were identified in the ALS gene sequencing, W574L and S653N, conferring resistance to sulfonilureas and imidazolinones. The weed control experiment, overal, herbicide tank mixtures achieved higher levels of control. Therefore, this research confirms the introduction of A. palmeri to Brazil, as well as its multiple resistance to EPSPS and ALS inhibitor herbicides. Its control is more efficient with herbicide mixtures, which guarantees more susteinable use of the new herbicide-tolerant crop technologies.

Water scarcity induced by drought, temperature, and salinity has plagued agricultural sustainability in recent years with unprecedented revenue losses, raising concerns for worldwide food security. Recent studies have revealed unique botanical response mechanisms to combat water related stress, namely the expression of proteins known as the dehydrins. Dehydrin proteins have been shown to serve various intracellular protective functions. The gene for a SK5 type dehydrin from the arctic plant Cerastium arcticum (CaDHN) was introduced into tobacco plants and water deficit tolerance was evaluated. Plants overexpressing CaDHN displayed improved tolerance to salt stress, but no improvement was observed under drought stress. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2015. / FAU Electronic Theses and Dissertations Collection

O solo é um recurso natural imprescindível para a manutenção da vida, mas seu uso intensivo e incorreto tem acelerado o seu processo de degradação, o que compromete a sustentabilidade dos sistemas agrícolas e do ambiente. Entretanto, práticas de manejo que incluem o preparo de solo com baixo ou nenhum grau de revolvimento, e sistemas de culturas com alta adição de carbono (C) ao solo, parecem estar entre as mais importantes para restabelecer a qualidade do solo. Desse modo, os atributos que têm íntima relação com a MOS (matéria orgânica do solo), como os microorganismos do solo, têm maior potencial de serem adotados como indicadores de qualidade do solo. A partir disso, esse trabalho teve como objetivo avaliar a dinâmica da microbiota do solo cultivado com diferentes culturas com potencial agroenergético (cana-de-açúcar a soja e o milho) sob diferentes formas de manejo, a partir da quantificação de indicadores biológicos de qualidade do solo, tomando-se como referência o solo sob condições de Cerrado nativo adjacente. Amostras de solo foram coletadas de lavouras comerciais da Fazenda Brejinho (Pedro Afonso-TO), nas profundidades de 0 a 5 cm e 5 a 10 cm. Foram determinados o carbono da biomassa microbiana, o carbono orgânico total, a respiração microbiana e foram calculados os quocientes metabólico e microbiano. O carbono da biomassa microbiana e a respiração microbiana sofreram alterações em função do manejo adotado nas diferentes culturas, sendo que, o solo sob cultivo de cana-de-açúcar, sob preparo convencional e sem rotação de culturas, sofreu maior redução da atividade microbiana quando comparado aos solos sob demais culturas e formas de manejo. Por outro lado, para manter e melhorar a qualidade do solo, é necessário adotar técnicas de manejo mais conservacionistas que propiciem menor revolvimento do solo, possibilitando maior retenção de água e a manutenção da umidade do solo, e tendo a rotação de culturas como fonte adição de C ao solo e de diversidade microbiana. / Soil is an essential natural resource for life maintenance, but intensive and incorrect uses have accelerated the degradation process of this resource, which compromises the agricultural systems and environmental sustainability. However, management practices including low soil disturbance and cropping systems with high C addition to the soil appear to be among the most important to restore soil quality. Thus, the attributes, which have an intimate relationship with the soil organic matter, such as soil microorganisms, have the greatest potential to be used as indicators of soil quality. After that, in this study we aimed to evaluate the soil microbial communities dynamic under differents agro-energy cropping systems, such as sugarcane, soybeans and corn, and we used the soils under native Cerrado as reference. The soil samples were collected on commercial fields from Brejinho Farm (in Pedro Afonso municipality, Tocantins State), considering two depths, 0-5 cm and 5-10cm. We determined the microbial biomass carbon, total organic carbon, microbial respiration, and we calculated the metabolic quotient (qCO2) and the microbial quotient (qM). The microbial biomass carbon and microbial respiration were changed by the different cropping systems. The sugarcane cropping system, which involved conventional tillage, without crop rotation, suffered greater reduction of microbial activity compared with the cropping systems under no-till. Thus, to maintain and increase soil quality, it is necessary to expand the conservation management techniques adoption that provide less soil disturbances and increase soil aggregation, allowing water retention and maintenance of soil moisture, and with crop rotation as a source of C addition to soil and microbial diversity.