<p>As the world population continues to grow, it will be challenging to manage resources, reduce environmental pollution and maintain growing demand for food production. Controlled environment agriculture (CEA) is a novel solution to reduce freshwater use in agriculture, minimize environmental pollution from agriculture sector, and meet the growing food demand. CEA allows for the year-round cultivation in inhospitable climatic conditions. Hydroponics is a common method of growing crops in CEA, where plants grow in a solution enriched with nutrients and oxygen. The technique significantly reduces water use and fertilizer run-off during production. In the United States, lettuce is one of the most important crops grown using hydroponics.</p> <p> Hydroponic production uses several methods to grow lettuce including nutrient film technique (NFT) and constant flood table (CFT). Moreover, several cultivars of lettuce are grown in the Midwest. There is a lack of knowledge on whether optimal fertilizer concentrations change depending on the cultivar or hydroponic production system. Little information is known about the suitability of a cultivar to a specific method of hydroponic production. For year-round lettuce production in hydroponics, supplemental lighting (SL) and heating are required in the Midwestern regions of the U.S. The energy requirements for SL and heating can be too costly in winter for some growers to produce crop year-round. In addition to light quantity, spectral composition of light can impact growth. Heating the root zone to produce a micro-climate may be more efficient than heating the entire greenhouse and possibly reduce overall heating costs. However, information on spectral composition of light and the efficacy of root zone heating is unclear, at best. Certain cultivars that can tolerate cold stress can be more suitable in the U.S. Midwest during winter. Lettuce cultivar screening for yield under cooler environments is limited. </p> <p> A completely customizable hydroponic production system that can aid in conducting research related to above-mentioned issues was built as a part of my Master of Science program. Using this system, 24 popular cultivars from four lettuce groups were evaluated for productivity during summer/fall under different concentrations of fertilizer solution, and in two production methods including NFT and CFT during spring. In addition, yield of all 24 cultivars were evaluated under 10, 15.5 and 21.1 °C in a growth chamber. The eight best performing cultivars from the summer/fall trial were evaluated during the winter in a greenhouse with the addition of SL and root zone heating with minimal ambient air heating. </p> <p> Results indicated that the lowest level of electrical conductivity (EC) of the fertilizer solution used (1.3 dS·m^-1) resulted in highest yield, regardless of cultivar or method of production. Among the 24 cultivars; Red Sails (Leaf), Salvius (Romaine), Cedar (Oakleaf), and Adriana (Butterhead) had the highest yields among each group during summer. Growth chamber study indicated that Dragoon, Adriana, New Fire Red and Red Sails cultivars had higher yields than other cultivars under cooler (10 and 15.5 °C) air temperature conditions. In the winter study, lettuce cultivars did not reach harvestable size even after 40 days of growth without SL and root zone heating. Supplemental light composition significantly affected lettuce growth with higher yield under Purple (with higher proportion of red) than White LED lighting. Commercially acceptable lettuce could be produced using root zone heating. In general, plants grown under CFT yielded higher than those grown under NFT in the winter trial. Among the cultivars, Salvius, Black Seeded Simpson, Cedar, and Red Sails performed better under SL and root zone heating during winter.</p>

This thesis covers two separate studies. The first study, chapter 2, was conducted to evaluate whether there are additional economic returns from producing strawberries in the high tunnel compared to the open-field in Southeast Virginia. We develop and compare budgets for eight strawberry cultivars grown in the two environments and sold under three marketing strategies (pre-pick wholesale, pre-pick retail, and U-pick). Almost all cultivars in the high tunnel generated negative net revenues regardless of the marketing strategy. In contrast, net revenues from open-field cultivars were always positive. In the second study, chapter 3, we used a fractional multinomial logit model to estimate the effect of crop revenues, input costs, and fuel ethanol production on the joint acreages planted to eight U.S major crops (barley, corn, cotton, peanuts, rice, sorghum, soybeans, and wheat). We found a positive and statistically significant marginal effect of the expected peanuts' revenue on its acreage share. The expected corn revenue had a negative average marginal effect on soybean acreage share, and the effect of expected wheat revenue was positive on cotton acreage share and negative on rice acreage share. / Master of Science / This thesis covers two separate research studies. The first study, chapter 2}, was conducted to evaluate whether growing strawberries in a simple, low-cost, and passive heat structure known as a "high tunnel" would yield more profit (the difference between total revenues and total costs) compared to growing them outside in an open-field in Southeast Virginia. We estimate and compare differences between total revenues and costs for eight strawberry cultivars grown in the two environments and sold under three marketing strategies. The first two marketing strategies involve growers harvesting strawberries themselves. They can then either retail them (farm stands, farmers' markets, or in a similar setting: pre-pick retail) or sell them in bulk to be retailed by others (pre-pick wholesale). A third marketing strategy involves consumers visiting a farm and picking their own strawberries (U-pick). Almost all cultivars grown in the high tunnel structure resulted in a loss (negative difference between total revenues and costs) regardless of the marketing strategy. In contrast, cultivars produced in the open-field always generated a profit (positive total revenues and costs difference). In the second study, chapter 3, we estimated the effect of crop revenues, input costs, and fuel ethanol production on acreages planted to eight U.S major crops (barley, corn, cotton, peanuts, rice, sorghum, soybeans, and wheat), and we considered the fact that acreages allocated to one crop affect other crops' acreages. We found that increasing the expected revenue of peanuts leads to an increase in its acreage share. Increasing the expected revenue of corn leads to a decrease in soybeans' acreage share. Finally, increasing the expected revenue of wheat leads to an increase in the cotton acreage share and a decrease in the rice acreage share.

Магистерская диссертация состоит из введения, обзора литературы, описания материалов и методов, результатов и их обсуждений, выводов и списка литературы. Материалы работы изложены на 75 страницах (основного текста). Работа содержит 3 таблицу, 104 рисунка, 2 приложения. Список литературы включает 104 источника, из которых 19 отечественных и 85 иностранных. Цель исследования: Выявить диагностическую роль анатомо-морфологических и эколого-биологических признаков отдельных представителей рода Begonia L., культивируемых на кафедре биоразнообразия и биоэкологи ИЕНиМ УрФУ и в оранжереях Ботанического сада УрФУ и УрО РАН. Объектами исследования являются виды и культивары рода Begonia L., выращиваемых на кафедре биоразнообразия и биоэкологии ИЕНиМ УрФУ и в оранжереях Ботанических садов УрФУ и УрО РАН. В работе изучались анатомо-морфологические характеристики видов и культиваров, состоящие в 8 разных секциях: Begonia, Diploclinium, Gaerdtia, Gireoudia, Knesebeckia, Platycentrum, Pritzelia, Weilbachia. Актуальностью настоящей работы является изучение видов и культиваров рода Begonia L., так как группа является крайне разнородной и уникальной, обладающая важным экономическим потенциалом. Представители данного рода могут стать одними из модельных объектов для изучения биоразнообразия и развития подходов для его сохранения. Важным является и то, что в исследования необходимо вовлекать не только дикорастущие виды, но и огромный объем культиваров, входящие в этот род. Также согласно современным исследованиям, бегонии имеют потенциал растений, обладающими лекарственными свойствами, что крайне важно для будущих и возможных фармацевтических исследований и создания медицинских препаратов. В результате проведенных исследований, на основании изученых анатомо-морфологических характеристик таксонов, были выявлены диагностические признаки 8 секций и проведен анализ соотношения выявленных признаков с эколого-биологическими особенностями представителей рода Begonia L. / Master's dissertation consists of an introduction, a literature review, a description of materials and methods, results and their discussions, conclusions, and a list of references. The materials of the work are presented on 75 pages (main text). The work contains 3 tables, 104 figures, 2 appendices. The list of references includes 104 sources, of which 19 are domestic and 85 are foreign. Purpose of the study: To reveal the diagnostic role of anatomical-morphological and ecological-biological characters of individual representatives of the genus Begonia L. cultivated at the Department of Biodiversity and Bioecology of the Institute of Natural Sciences and Metrology of the UrFU and in the greenhouses of the Botanical Garden of the Ural Federal University and the Ural Branch of the Russian Academy of Sciences. The objects of research are the species and cultivars of the genus Begonia L. grown at the Department of Biodiversity and Bioecology of the Institute of Natural Sciences and Mathematics of the Ural Federal University and in the greenhouses of the Botanical Gardens of the Ural Federal University and the Ural Branch of the Russian Academy of Sciences. The work studied the anatomical and morphological characteristics of species and cultivars, consisting of 8 different sections: Begonia, Diploclinium, Gaerdtia, Gireoudia, Knesebeckia, Platycentrum, Pritzelia, Weilbachia The relevance of this work is the study of species and cultivars of the genus Begonia L., since the group is extremely diverse and unique, with important economic potential. Representatives of this genus can become one of the model objects for studying biodiversity and developing approaches for its conservation. It is also important that research should involve not only wild-growing species but also a huge volume of cultivars belonging to this genus. Also, according to modern research, begonias have the potential of plants with medicinal properties, which is extremely important for future and possible pharmaceutical research and the creation of medicines. As a result of the studies carried out, on the basis of the studied anatomical and morphological characteristics of taxa, diagnostic features of 8 sections were identified, and the analysis of the correlation of the identified characters with the ecological and biological characteristics of representatives of the genus Begonia L.

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No. of bitstreams: 2 dissertacao_mairson_robson_santana.pdf: 449314 bytes, checksum: 2f64f3164fbbd2b67a5e54e5f635bf85 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2015-08-17 / Sem bolsa / A soja é a principal cultura do cerrado brasileiro na atualidade. O sistema de multiplicação e comércio de sementes é regido pela Lei de Sementes nº 10.711, de 5 de agosto de 2003 e o registro de cultivares é regido pela Lei de Proteção de Cultivares (LPC) nº. 9.456 de 25 de abril de 1997, que a instituiu LPC, e do Decreto n. 2.366 de 5 de novembro de 1997 que a regulamentou. Dentro desse sistema legal há todas as regras para o uso de sementes no Brasil. Essa sistemática é importante porque organiza o sistema de coleta de royalties para os obtentores, o acesso do agricultor a variedades e sementes de melhor qualidade safra após safra. Nesse processo são estabelecidos as categorias de sementes que em ordem crescente mostra a pureza da cultivar com relação as suas características fenológicas sendo estas: Genética, Básica, C1, C2 essas se refere as semente Certificadas e S1, S2 que se refere a sementes fiscalizadas. Dentro desse processo é facultado ao agricultor salvar a sua semente para o Uso Próprio em propriedade de seu domínio. Essa permissão ao agricultor não estabelece até que tamanho de área ele pode fazer o uso próprio e nem estabelece uma forma de remuneração ao Obtentor da cultivar. Com isso na safra de 2014/2015 foi notada no mercado uma explosão de agricultores com intenção de salvar semente cultivando soja safrinha no cerrado. Esse trabalho representa um registro e um copilado das ações e desdobramento do setor para permitir a cobrança de royalties e como ele está sendo arbitrado no mercado com contratos pelos obtentores de biotecnologias, tentativas de barrar o cultivo da soja safrinha, ações judiciais contra obtentores de tecnologia e a tentativa do agricultores de ter menor custo e qualidade de semente compatível com o que garante a Lei de Sementes. Como conclusão o setor sementeiro precisa mudar suas práticas de comercialização e é necessário garantir uma remuneração ao obtentor da cultivar nos casos que o agricultor salva semente como forma de garantir a continuidade das pesquisas e desenvolvimento de novas cultivares. / Soybean is currently the main crop of the Brazilian Cerrado. The seed production and trade system is governed by the Seed Act No. 10.711 of August 5th, 2003 and cultivar registration is ruled by the Plant Variety Protection Act no. 9456 of April 25th, 1997, which is regulated by the Decree n. 2366 of November 5th, 1997. All the rules for seed usage in Brazil are embedded in this legal system. This systematic is important because it organizes the collection of royalties for breeders and the access of farmers to cultivars and better quality seeds in every season. In this process, the categories of seeds are established in descending order of purity of the cultivar regarding their phenological characteristics as it follows: “Genética” (Genetic, equivalent to Breeder Seed), “Básica” (Basic, equivalent to Foundation Seed), “C1” (Certified Seed 1, equivalent to Registered Seed) and “C2” (Certified Seed 2, equivalent to Certified Seed) which concerns the certified seed system and “S1” and “S2” that refers to audited seeds. In this system, the farmers are entitled to save seeds for own use in their lands. Such permission does not set the size of the area that farmers can make own use and does not establish a form of remuneration to breeders. Thus, a burst of farmers intending to save seeds, planting off-season soybeans, was noted in the 2014/15 season in the Cerrado. This work represents a record and a complied of the actions and industry unfolding to allow the collection of royalties and how it is being arbitrated in the market with contracts by biotechnology companies, attempts to stop the cultivation of soybean off-season, lawsuits against biotechnology companies and farmers’ attempts to obtain lower costs and seed quality compatible with what is ensured by Seeds Act. In conclusion, the seed sector must change its marketing practices and it is necessary to guarantee remuneration to the breeder in cases where the farmer saved seeds in order to ensure the continuity of research and the development of new cultivars

Infection of barley (Hordeum vulgare) leaves with the rust fungus, Puccinia hordei, causes changes in the host protein synthesis. This thesis analyses these changes in the barley cultivar Triumph following inoculation of 7-day-old leaves with either a virulent or an avirulent race of P. hordei. The initial approach was to isolate membrane-bound polysomes from infected leaves, translate them in vitro and analyse the translation products. These products include the integral membrane proteins which were expected to be involved in the response of the host to the pathogen. A method based on differential centrifugation in the presence of a ribonuclease-inhibiting buffer was developed for separating membrane-bound polysomes from the rest of the cytoplasmic polysomes. Membrane-bound polysomes were found to comprise one fifth of the total polysomes in the leaves. Analysis of the translation products of membrane-bound polysomes by SDS-PAGE showed them to be of higher average molecular weight than those from free polysomes. Comparison of polypeptides produced by membrane-bound polysomes from healthy and inoculated plants showed some differences however the low yield of membrane-bound polysomes made it difficult to obtain conclusive results. Thus it was decided to isolate total polysomes by including 1% Triton X-100 in the extraction buffer. Polysomes were extracted from 12 to 72 h after inoculation. Infection caused a decline in yield of polysomes during this period when compared with healthy leaves of the same age. Polysomes isolated 16 h after inoculation with the virulent race were 20% less efficient at translation than polysomes from control leaves. In contrast polysome isolated from leaves inoculated with the avirulent race were 20% more efficient. Analysis of the labelled translation products by SDS-PAGE and fluorography showed relative increases in the synthesis of some proteins by 16 h after inoculation with either race when compared to products from healthy leaves. Protein synthesis in the infected plants was further analysed by in vivo labelling and one- and two-dimensional PAGE. The fluorographs revealed increased synthesis of a group of proteins from 58 to 116 kDa starting 12 h after inoculation with either race of P. hordei; confirming the results from the polysome translations. Two polypeptides with molecular weights of about 66 kDa were found to increase following infection only with the virulent race. By three days after inoculation with either fungal race the most obvious change in protein synthesis was a marked decrease in the synthesis of the two most prominent polypeptides with molecular weights of 15 and 51 kDa which were considered to be the subunits of ribulose bisphosphate carboxylase. The elicitor hypothesis, in attempting to explain cultivar-specific resistance in plants, postulates that resistance is controlled by the interaction of specific fungal elicitors and plant receptors and that this interaction which only occurs between resistant hosts and avirulent pathogens triggers specific gene expression leading to resistance. This hypothesis does not fit the situation in the barley-P. hordei interaction as protein synthesis showed similar changes following infection with either a virulent or an avirulent race.

Agricultural management is essential for achieving optimum crop production and maintaining soil quality. Soil microorganisms are responsible for nutrient cycling and are an important consideration for effective soil management. The overall goal of the present research was to better understand microbial communities in agricultural soils as they relate to soil management practices. For this, we evaluated the differential impact of two contrasting drainage practices on microbial community composition and characterized active denitrifiers from selected agricultural sites. Field drainage is important for crop growth in arable soils. Controlled and uncontrolled tile drainage practices maintain water in the field or fully drain it, respectively. Because soil water content influences nutrient concentration, moisture, and oxygen availability, the effects of these two disparate practices on microbial community composition was compared in paired fields that had diverse land management histories. Libraries of the 16S rRNA gene were generated from DNA from 168 soil samples collected from eight fields during the 2012 growing season. Paired-end sequencing using next-generation sequencing was followed by read assembly and multivariate statistical analyses. Results showed that drainage practice exerted no measureable effect on the bacterial communities. However, bacterial communities were impacted by plant cultivar and applied fertilizer, in addition to sampled soil depth. Indicator species were only recovered for depth; plant cultivar or applied fertilizer type had no strong and specific indicator species. Among indicator species for soil depth (30-90 cm) were Chloroflexi (Anaerolineae), Betaproteobacteria (Janthinobacterium, Herminiimonas, Rhodoferax, Polaromonas), Deltaproteobacteria (Anaeromyxobacter, Geobacter), Alphaproteobacteria (Novosphingobium, Rhodobacter), and Actinobacteria (Promicromonospora). Denitrification in agricultural fields transforms nitrogen applied as fertilizer, reduces crop production, and emits N2O, which is a potent greenhouse gas. Agriculture is the highest anthropogenic source of N2O, which underlines the importance of understanding the microbiology of denitrification for reducing greenhouse gas emissions by altered management practices. Existing denitrifier probes and primers are biased due to their development based mostly on sequence information from cultured denitrifiers. To circumvent this limitation, this study investigated active and uncultivated denitrifiers from two agricultural sites in Ottawa, Ontario. Using DNA stable-isotope probing, we enriched nucleic acids from active soil denitrifiers by exposing intact replicate soil cores to NO3- and 13C6-glucose under anoxic conditions using flow-through reactors, with parallel native substrate controls. Spectrophotometric chemistry assays and gas chromatography confirmed active NO3- depletion and N2O production, respectively. Duplicate flow-through reactors were sacrificed after one and four week incubation periods to assess temporal changes due to food web dynamics. Soil DNA was extracted and processed by density gradient ultracentrifugation, followed by fractionation to separate DNA contributed by active denitrifiers (i.e., “heavy” DNA) from that of the background community (i.e., “light” DNA). Light and heavy DNA samples were analyzed by paired-end sequencing of 16S rRNA genes using next-generation sequencing. Multivariate statistics of assembled 16S rRNA genes confirmed unique taxonomic representation in heavy fractions from flow-through reactors fed 13C6-glucose, which exceeded any site-specific or temporal shifts in putative denitrifiers. Based on high relative abundance in heavy DNA, labelled taxa affiliated with the Betaproteobacteria (71%; Janthinobacterium, Acidovorax, Azoarcus, Dechloromonas), Alphaproteobacteria (8%; Rhizobium), Gammaproteobacteria (4%; Pseudomonas), and Actinobacteria (4%; Streptomycetaceae). Metagenomic DNA from the original soil and recovered heavy fractions were subjected to next-generation sequencing and the results demonstrated enrichment of denitrification genes with taxonomic affiliations to Brucella, Ralstonia, and Chromobacterium in heavy fractions of flow-through reactors fed 13C6-glucose. The vast majority of heavy-DNA-associated nitrite-reductase reads annotated to the copper-containing form (nirK), rather than the heme-containing enzyme (nirS). Analysis of recovered nirK genes demonstrated low sequence identity across common primer-binding sites used for the detection and quantification of soil denitrifiers, indicating that these active denitrifiers would not have been detected in molecular surveys of these same soils.

The yield of common bean crop is affected by high air temperature during the reproductive phase. The experiment was carried out in pots and in growth chambers (phytotron) with controlled air temperature and humidity. The objective of this study was to identify the most appropriate substrate for common bean grown in pots and to evaluate common bean genetic variability for tolerance to high air temperature during the pre-flowering (R5) to pod formation (R7) phase. To identify the most appropriate substrate two experiments were carried out in a greenhouse during 2005, with the TPS Nobre common bean cultivar. Seven substrates were evaluated: Plantmax®, carbonized rice husks, vermiculite, sand, carbonized rice husks + 20% of Plantmax®, carbonized rice husks + 20% of vermiculite and carbonized rice husks + 20% of sand. The experimental design was a completely randomized with five replications. To evaluate the genetic variability under high temperature the experiment was conducted in phytotron, with controlled temperature, lighting and photoperiod and all other conditions for growing were optimum. During the R5-R7 phase, plants were submitted to air temperature of 30°C during one hour a day. The experimental design used was completely randomized with three repetitions, with 20 common bean cultivars. In the substrate evaluation, it was possible to observe chemical and physical characteristics among the substrates. The substrate Plantmax® provided the most appropriate characteristics leading to the best conditions for growing and development of common bean plants. The cultivars showed different us in phonological, reproductive, yield traits and components indicating genetic variability for tolerance to high temperature during the reproductive phase (R5 to R7). Cultivars Pérola, TPS Bonito, BRS Valente and Corrente were tolerant to the air temperature of 30°C during one hour a day during the reproductive period. / A cultura do feijão tem sua produtividade afetada em condições de alta temperatura do ar durante o período reprodutivo. A avaliação dos danos causados as estruturas reprodutivas são melhor realizadas em câmara controlada (fitotron), com controle de temperatura e de umidade. Sendo assim, foram objetivos desse trabalho: (1) identificar o substrato mais apropriado para o cultivo de feijão em vasos; (2) avaliar a variabilidade genética do feijão para tolerância a alta temperatura do ar, durante o período de pré-floração (R5) à formação de vagens (R7). Para identificar o substrato mais adequado foram conduzidos dois experimentos em casa-de-vegetação, durante o ano de 2005, com a cultivar de feijão TPS Nobre. Sete substratos foram avaliados: Plantmax®, casca de arroz carbonizada, vermiculita, areia, casca de arroz carbonizada + 20% Plantmax®, casca de arroz carbonizada + 20% vermiculita e casca de arroz carbonizada + 20% areia. O delineamento experimental utilizado foi inteiramente casualizado, com cinco repetições. A avaliação da variabilidade genética para a alta temperatura do ar foi realizada em fitotron, com controle de temperatura, luz, fotoperíodo e demais condições ótimas de cultivo. Durante o subperíodo R5-R7 às plantas foram submetidas à temperatura de 30oC, durante uma hora diariamente. O delineamento experimental utilizado foi o inteiramente casualizado, com três repetições, e avaliaram-se 20 cultivares de feijão. Na avaliação de substratos, foi possível observar diferenças químicas e físicas entre os substratos. A utilização do substrato comercial Plantmax® propiciou melhores condições para o crescimento e o desenvolvimento das plantas de feijão, devido as características químicas e físicas mais apropriadas. As cultivares de feijão apresentaram comportamento diferenciado quanto à fenologia, caracteres reprodutivos e componentes da produção evidenciando a presença de variabilidade genética para tolerância a alta temperatura do ar durante o período reprodutivo (R5 a R7). As cultivares Pérola, TPS Bonito, BRS Valente e Corrente são tolerantes a temperatura do ar de 30oC, por uma hora, durante o período reprodutivo.

Der Klimawandel fordert die Anbausysteme heraus, um das derzeitige Produktionsniveau zu verbessern oder sogar aufrechtzuerhalten. Es wird erwartet, dass zukünftige Trends bei Temperatur und Niederschlag die Ernteproduktivität beeinträchtigen. Es ist daher notwendig, möglicher Lösungen zur Anpassung der Anbausysteme an den Klimawandel zu untersuchen. Ziel dieser Arbeit ist es, das Wissen über die Anpassung von weltweit relevanten Getreidepflanzen an den Klimawandel zu erweitern. Die zentrale Fragestellung ist, ob globale Anbausysteme an den Klimawandel angepasst werden können, indem die Phänologie der Kulturpflanzen durch Anpassung von Wachstumsperioden und Sorten gesteuert wird. Die Phänologie und die Ertragsreaktionen sowohl auf den Temperaturanstieg als auch auf die Sortenselektion werden zunächst anhand eines Ensembles von “Global Gridded Crop Models” bewertet. Anschließend wird die Komplexität der Anpassung durch phänologisches Management analysiert, insbesondere unter Berücksichtigung der bestehenden großen Wissenslücken bei der Auswahl von Pflanzensorten. Das Ergebnis der Analyse ist ein regelbasierter Algorithmus, der phänologische Zyklen der Kulturpflanzen auswählt, um die Zeit für die Ertragsbildung zu maximieren und Temperatur- und Wasserbelastungen während der Wachstumszyklen der Kulturpflanzen zu minimieren. Die berechneten Aussaatdaten und Wachstumsperioden werden verwendet, um globale Muster von Sorten zu parametrisieren, die an aktuelle und zukünftige Klimaszenarien angepasst sind. Diese Arbeit zeigt, dass die Auswirkungen des Klimawandels auf die Pflanzenproduktivität erheblich variieren können, je nachdem, welche Annahmen für das agronomische Management getroffen werden. Änderungen im Management zu vernachlässigen, liefert die pessimistischste Prognose für die zukünftige Pflanzenproduktion. Relativ einfache Ansätze zur Berechnung angepasster Aussaatdaten und Sorten bieten eine Grundlage für die Berücksichtigung autonomer Anpassungsschemata als integraler Bestandteil globaler Modellierungsrahmen. / Climate change is challenging cropping systems to enhance or even maintain current production levels. Future trends in temperature and precipitation are expected to negatively impact crop productivity. It is therefore necessary to explore adaptation options of cropping systems to changing climate. The aim of this thesis is to advance knowledge on adaptation of world-wide relevant grain crops to climate change. The central research question is whether global cropping systems can be adapted to climate change by managing crop phenology through adjusting growing periods and cultivars. Phenology and yield responses to both temperature increase and cultivar selection are first assessed making use of an ensemble of Global Gridded Crop Models. Then, the complexity of adaptation through phenological management is analysed, particularly addressing the existing large knowledge gaps on crop cultivar choice. The outcome of the analysis is a rule-based algorithm that selects crop phenological cycles aiming at maximizing the time for yield formation and minimizing temperature and water stresses during the crop growth cycles. The computed sowing dates and growing periods are used to parametrize global patterns of cultivars adapted to present and future climate scenarios. This thesis demonstrates that the impacts of climate change on crop productivity can vary substantially depending on which assumptions are made on agronomic management. Neglecting any changes in management return the most pessimistic projection on future crop production. Relatively simple approaches to compute adapted sowing dates and cultivars provide a base for considering autonomous adaptation schemes as an integral component of global scale modelling frameworks.

La culture d’associations de variétés sensibles et résistantes au sein d’une même parcelle permet de réduire la propagation des maladies fongiques foliaires aériennes. L’architecture des plantes a un impact sur la dispersion de spores et le microclimat, mais est rarement prise en compte dans la conception des associations. L’objectif de cette thèse était de comprendre le rôle joué par l’architecture dans des associations de variétés différant par leur niveau de résistance à une maladie dispersée par éclaboussement, la septoriose du blé, causée par Zymoseptoria tritici. Une expérimentation en conditions contrôlées a permis de quantifier des relations entre interception de spores et architecture des couverts. Des différences de densité entre couverts purs et associés ont donné lieu à une réduction du niveau de maladie sur les plantes sensibles cultivées en association par rapport à celles cultivées pures. Lors d’une expérimentation au champ, les associations de variétés de hauteurs de tiges contrastées étaient moins malades que celles ayant des hauteurs similaires. Ces résultats ont été mis en relation avec des effets de l’architecture sur la dispersion de spores et la durée d’humectation au sein des couverts. Une approche de modélisation spatialement explicite a permis d’identifier des mécanismes de dispersion par éclaboussement liés à l’architecture des couverts associés. Dans des associations de variétés de hauteurs différentes, la quantité d’inoculum éclaboussée dépendait de la surface foliaire présente au dessus des feuilles malades (effet parapluie). La quantité d’inoculum interceptée par un étage foliaire était liée à la différence de hauteur entre la source d’inoculum et l’étage foliaire (effet hauteur). Les différences de hauteur de plantes entre variétés d’une association ont modulé l’interception de spores par des feuilles résistantes (effet barrière). Nos résultats suggèrent qu’une prise en compte de l’architecture des variétés dans la conception des associations variétales permettrait de mieux maîtriser les maladies par éclaboussement. / Growing mixtures of susceptible and resistant cultivars in the same field makes it possible to reduce the propagation of airborne fungal plant diseases. Plant architecture has an impact on spore dispersal or microclimate, but is rarely taken into account in mixture design. The objective of this work was to understand the role of canopy architecture in mixtures of cultivar of different levels of resistance to a disease dispersed by rain-splash, septoria tritici blotch, caused by Zymoseptoria tritici. A controlled conditions experiment made it possible to quantify relationships between spore interception and canopy architecture. Differences of canopy density between pure stands and mixtures led to a reduction in disease on susceptible plants grown in mixture, compared to the susceptible pure stand. During a field experiment, mixtures of cultivars with contrasted stem height were less diseased than those with similar stem height. These results were related to the effect of canopy architecture on spore dispersal and leaf wetness duration. A spatially explicit modeling approach made it possible to identify splash dispersal mechanisms related to the architecture of mixed canopies. In mixtures of cultivar with diverse plant height, the amount of splashed inoculum depended on leaf area located above diseased leaves (umbrella effect). The amount of inoculum intercepted by a leaf layer was related to its difference of height between the inoculum sources (height effect). Differences of plant height between cultivars composinga mixture modulated the interception of spores by resistant leaves, providing an increased protection of susceptible leaves (barrier effect). Our results suggest that considering cultivar architecture in the design of cultivar mixtures could make it possible to improve the management of splash-dispersed diseases.

Indiana University-Purdue University Indianapolis (IUPUI) / Winter survival is variable among commercially grown strawberry (Fragaria x ananassa) cultivars. The main objectives of this study were to evaluate the molecular basis that contribute to this difference in strawberry cultivars and to identify potential biomarkers that can be used to facilitate the development of new strawberry cultivars with improved overwintering hardiness. With these goals in mind, the freezing tolerance was examined for four cultivars, ‘Jonsok’, ‘Senga Sengana’, ‘Elsanta’, and ‘Frida’ (listed from most to least freezing tolerant based on survival from physiological freezing experiments) and the protein expression was investigated in the overwintering relevant crown structure of strawberry. Biomarker selection was based on comparing the protein profiles from the most cold-tolerant cultivar, ‘Jonsok’ with the least cold-tolerant cultivar ‘Frida’ in a comprehensive investigation using two label-free global proteomic methods, shotgun and two dimensional electrophoresis, with support from univariate and multivariate analysis. A total of 143 proteins from shotgun and 64 proteins from 2DE analysis were identified as significantly differentially expressed between ‘Jonsok’ and ‘Frida’ at one or more time points during the cold treatment (0, 2, and 42 days at 2 ºC). These proteins included molecular chaperones, antioxidants/detoxifying enzymes, metabolic enzymes, pathogenesis related proteins and flavonoid pathway proteins. The proteins that contributed to the greatest differences between ‘Jonsok’ and ‘Frida’ are candidates for biomarker development. The novel and significant aspects of this work include the first crown proteome 2DE map with general characteristics of the strawberry crown proteome, a list of potential biomarkers to facilitate the development of new strawberry cultivars with improved cold stress tolerance.