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Seeds are essential elements within agricultural production and food systems. However, seed systems face multiple issues, including processes of commercialisation, privatisation, and crop diversity loss, that require reconsidering current approaches to seeds and varieties. Seed initiatives hold a potential to contribute to alternative and desirable seed system configurations and outcomes. In this thesis, I analyse how existing seed initiatives increase their impact, drawing on the typology of amplification processes by Lam et al. (2020). Furthermore, due to the long-term occurrence of variety losses and the complexity of the processes involved, this thesis uses system dynamics concepts and diagramming tools to map the use of local varieties from the initiatives’ perceptions. Thereby, I attempt to operationalise amplification, depict local variety use, and combine the two approaches within the context of seed initiatives. I employ a case-study approach in Italy and conducted semi-structured interviews with members of six seed initiatives. Concrete actions for almost all the frameworks’ processes were found. Building stability, influencing values and mindsets, and strategically impacting higher institutional levels emerged as suitable ways to amplify and might indicate that initiatives prepare and potentially navigate change. Enhancing the initiatives’ impact range and speed benefitted from more nuance due to diverging notions on these processes. A qualitative systems diagram with social and ecological components maps causal structures that influence the use of local varieties, showing a potential for desirable dynamics. By indicating how amplifying actions relate to the system structure, I illustrate how the seed initiatives are influencing multiple system parts. Thus, the system maps revealed perceived system structure, which by itself might run the risk of portraying path dependency, while amplification relates to agency on how initiatives might influence the system.

Harvest Weed Seed Control (HWSC) concentrates, removes, or destroys weed seeds as they pass through the combine. Seed impact mills are modifications that are mounted directly to the back of a combine and are one way to implement HWSC. Seed impact mills kill weed seeds during harvest, preventing seeds from being added to the soil seedbank. Mills like the Redekop Seed Control Unit (SCU) and the integrated Harrington Seed Destructor (iHSD) could be used in soybean and wheat production in the eastern United States. Understanding the effectiveness and limitations of these mills is important for grower adoption. So, the aim of this research was to evaluate the efficacy of two seed impact mills, the Redekop SCU and the iHSD, in soybean and wheat. The first objective tested general seed kill of problematic species in soybean and wheat and seed kill in adverse conditions, such as high chaff flow rate into the mill and high chaff moisture. Results from objective one indicate that both the Redekop SCU and iHSD killed >98% and >91% of problematic weed seeds in soybean and wheat, respectively. Increases in chaff flow rate and chaff moisture resulted in a decrease in seed kill for specific species depending on the mill. But even at high chaff flow rates, seed kill remained >98% and >77% in soybean and wheat, respectively. At high chaff moisture, seed kill remained >98% and >74% in soybean and wheat, respectively. The second objective evaluated the percentage of weed seeds that bypassed the seed impact mill by exiting the combine in the straw fraction and the percentage of weed seeds that were killed when they entered the seed impact mill during harvest with a commercial combine. Results at field scale indicated that <5% of weed seeds bypassed the seed impact mill by exiting the combine in the straw fraction during harvest in soybean and wheat. Additionally, during a commercial harvest, the seed impact mills killed >99% and >89% of seeds in soybean and wheat, respectively. The third objective monitored population density changes for common ragweed (Ambrosia artemisiifolia) in soybean and Italian ryegrass (Lolium perenne ssp. multiflorum) in wheat following a harvest with a seed impact mill. Results from objective three indicated that in the growing season following a harvest with a seed impact mill, common ragweed density was reduced by 26% and 77% in the spring and fall, respectively, in soybean, and Italian ryegrass density was reduced by 48% in wheat. The fourth objective evaluated Palmer amaranth (Amaranthus palmeri) and its ability to shift its flowering timing in response to HWSC. If weeds flower earlier, they could shatter seeds earlier, and those seeds would bypass HWSC. Through selective breeding, two populations of Palmer amaranth experienced a shift in flowering timing such that the third generations flowered 54.7 and 41.0 days sooner in the greenhouse than the initial generations. In a common garden experiment, the second generations flowered 5.5 and 8.9 days sooner than the initial generations. These results indicate that seed impact mills, like the Redekop SCU and iHSD, can deliver high seed kill rates to a range of weed species at commercial scale in both soybean and wheat. Even in adverse conditions, the mills still killed >74% of seed from tested species. However, weed species can adapt to HWSC selection pressures, resulting in a loss of HWSC efficacy. Overall, this research indicates that seed impact mills are a good tool that growers can implement to reduce the number of weed seeds being returned to the soil seedbank. / Doctor of Philosophy / Herbicide resistance is a growing problem in global crop production systems. Weeds that escape control during the growing season can produce seeds by the time of crop harvest. During harvest, these weed seeds are captured by the combine, separated from the grain, and spread back into the field by the combine. Harvest weed seed control (HWSC) targets these weed seeds as they exit the combine by concentrating, removing, or destroying them. HWSC is a nonchemical weed control method that can be implemented as part of an integrated weed management system. One way to implement HWSC is through the use of seed impact mills, which are aftermarket modifications that can be installed on the back of the combine. These mills process the harvest residue and kill the weed seeds therein. Seed impact mills were initially designed for small grain production systems in Australia, but they have a potential fit in soybean and wheat production systems in the eastern United States as well. The purpose of this research was to evaluate two seed impact mills, the Redekop Seed Control Unit and the integrated Harrington Seed Destructor, for use in soybean and wheat. Stationary mill testing indicated that >98% and >91% of seeds from tested weed species were killed in soybean and wheat, respectively. Additionally, even in adverse conditions, seed kill was >98% for soybean weeds and >74% for wheat weeds. In the field, the results indicated that <5% of seeds were bypassing the mill in the straw fraction and being returned to the field during harvest. Results also indicated that >99% of soybean weed seeds and >89% of wheat weed seeds were killed when they entered the mill during a commercial harvest. Testing the mills in soybean production indicated that common ragweed density was reduced by 26% and 77% in the spring and fall, respectively, in the growing season following the use of a seed impact mill. Likewise, Italian ryegrass density was reduced by 48% following a harvest with a seed impact mill in wheat. The results indicate promise for using seed impact mills in soybean and wheat as a tool to reduce additions to the soil seedbank. However, weeds are known to adapt to management practices, and one way weeds might overcome HWSC is through earlier flowering, potentially leading to weed seeds falling on the ground before harvest and escaping capture by the combine. Through selective breeding, the time to flower for two populations of Palmer amaranth was shortened by 54.7 and 41.0 days in just three generations in the greenhouse, indicating that weeds could potentially adapt to HWSC, making it less effective.

Herbicide resistant weeds are driving implementation of integrated weed management (IWM). A new tactic to manage weeds is harvest weed seed control (HWSC), which targets weed seeds retained on the plant at crop harvest and either destroys, removes, or concentrates them. Research is limited on the effectiveness of HWSC in US cropping systems. For HWSC to be effective it is important to know when and how many seed are shed from a weed species in relation to crop harvest. Research was conducted to quantify when weed seed are shattered from 6 economically important weed species, four broadleaf (redroot pigweed, common ragweed, common lambsquarters, and common cocklebur) and two grass species (large crabgrass and giant foxtail). Results indicate that among summer annuals, broadleaf species retain larger proportions of their seed compared to grass species at the first opportunity for soybean harvest. As harvest was delayed, more seeds shattered from all species evaluated, indicating timely harvest is critical to maximizing HWSC effectiveness. Studies were conducted on grower fields in Virginia to evaluate the effectiveness of HWSC (field residue and weed seed removal). Results indicate that HWSC can significantly reduce populations of Italian ryegrass in wheat and common ragweed in soybean in the next growing season, but reductions were not observed for Palmer amaranth in soybean. Investigating IWM system for common ragweed control in soybean, HWSC was found to be less effective than soybean planting date (i.e. double cropping after wheat) at reducing common ragweed populations. However, the effectiveness of HWSC varied by location. If HWSC adoption were to become widespread, weeds could adapt by shedding seed earlier in the season. Research was conducted by growing Palmer amaranth populations from across the eastern US in a common garden. Currently there are differences in flowering time and seed shatter among Palmer amaranth populations based on the location of the maternal population, indicating potential for adaptation. This research demonstrates that HWSC is a viable option for weed management in US cropping systems but needs to be stewarded like any other weed management tool. / Doctor of Philosophy / Herbicide resistance in weeds is a growing problem in the US and around the world. Alternative methods of weed control must be adopted to maintain crop yields in the presence of herbicide-resistant weeds. Researchers and extension specialists strongly advise growers to adopt an integrated weed management (IWM) approach. Integrated weed management involves implementing multiple weed control tactics during a growing season. By using multiple methods of weed control within a given season the chances of weeds becoming resistant or adapting to any single tactic is reduced. Harvest weed seed control (HWSC) is a new tactic developed in Australia in response to herbicide resistance. HWSC targets weed seeds retained on the plant at crop harvest. In a normal crop harvest, the combine removes the grain and spreads crop residues (leaves, stalks, and other plant parts), including weed seeds, back across the field. When HWSC is implemented, weed seeds are destroyed (narrow windrow burning, cage mills) or concentrated and potentially removed from the field (chaff carts, direct bale, chaff lining). Thus, HWSC limits the number of weed seeds returned to the soil seed bank. There is limited research on HWSC and its integration with other tactics, in US cropping systems. For HWSC to be effective it is necessary for weed seeds to be retained on the mother plant in sufficient quantities at crop harvest. Research was conducted in Virginia to determine when weed seeds are shattered during the soybean growing season for 6 economically important weed species, four broadleaf (redroot pigweed, common ragweed, common lambsquarters, and common cocklebur) and two grass species (large crabgrass and giant foxtail). The broadleaf species retained >85% of their seed until the first opportunity for soybean harvest (mid-October). In the grass species, more seed shattered prior to soybean harvest with 50% of large crabgrass and 74% of giant foxtail seed being retained at the first opportunity for soybean harvest. When harvest was delayed seed continued to shatter and less was captured using HWSC. This research indicates broadleaf species are more suitable candidates for HWSC than grass species, among summer annuals. Further research on the ability of seed to germinate in relation to when seeds were shed was conducted on redroot pigweed, common ragweed and common lambsquarters. Results indicate that there are variable effects on germination of these species depending on when they were shed. HWSC was implemented on grower fields to assess the impact on weed populations of 3 weed species (Italian ryegrass, common ragweed, and Palmer amaranth). These experiments compared conventional harvest and HWSC (field residue and weed seed removal) when all other management strategies were the same within that field. Italian ryegrass tiller density in wheat varied by location but was reduced up to 69% in the spring following implementation of HWSC. By wheat harvest, HWSC reduced Italian ryegrass seed head density 67% at one location compared to conventional harvest. In soybean, common ragweed densities were reduced by 22 and 26% prior to field preparation and postemergence herbicide applications, respectively, in the HWSC plots compared to the conventional harvest plots. No differences were observed in common ragweed density by soybean harvest. No differences were observed with Palmer amaranth densities at any point during the soybean growing season. This research show that HWSC can reduce weed populations but is variable and additional research is still needed. IWM experiments were established across Virginia to compare soybean planting date (full season or double cropped), + cover crop (cereal rye/wheat or no cover), and + HWSC (field residue removal) to evaluate the best management strategy for common ragweed in soybean. Across all locations, double cropping soybean behind wheat had the greatest impact on common ragweed densities at the end of the first season. The impact of double cropping soybeans on common ragweed population is due to the emergence pattern of common ragweed; majority of common ragweed emerges prior to planting double cropped soybean (mid-June to early-July). HWSC was variable and only reduced common ragweed density at one of three locations. Widespread adoption of HWSC could place a selection pressure on weeds to shatter seed earlier in the season. A common garden experiment was conducted in Blacksburg, VA to assess Palmer amaranth populations collected from central Florida to southern Pennsylvania for differences in flowering time, time to seed shatter, and other phenotypic traits. Results indicate that latitude of the maternal population influences time to first flower with a 0.53 d reduction in flowering time for every degree north in latitude the maternal population was collected from. The strongest predictor of Palmer amaranth flowering time was emergence date/daylength. For every day emergence was delayed the time to first flower was reduced by 0.31 and 0.24 d for female and male plants, respectively. Time from emergence or first flower to first seed shatter was reduced by 0.48 or 0.17 d, respectively, for each day emergence was delayed. These results indicate that differences exist currently among Palmer amaranth populations and the selection pressure of HWSC could push these populations to flower and shatter seed early.

Species assembly into local communities from the surrounding region can be caused either by species failure to reach the site (i.e. seed limitation) or to establish (i.e. establishment limitation). The aim of this thesis was to investigate plant species assembly and to determine the relative importance of different factors in that process. In a cultivated landscape in southeast Sweden, plant community assembly was studied in grazed ex-arable fields. Community assembly from the surrounding region into the local community was explored using trait-based null models and seed sowing and transplanting experiments. The influence of local environmental factors and landscape history and structure on community assembly was also studied. In addition, differences in species assembly between ex-arable fields and semi-natural grasslands were explored. Seed limitation was the strongest filter on local community assembly. Only a fraction (36%) of species in a region dispersed to a local site and adding seeds/transplants increased species establishment. Species abundance at the regional scale, species dispersal method and seed mass strongly influenced which species arrived at the local sites. Establishment limitation also affected the assembly. Of species arriving at a site 78% did establish, seedling survival was low and which species established was influenced by species interactions, local environmental conditions and stochastic events. In addition, landscape structure that determined the species richness in the regional species pool influenced the local assembly. The comparison between assembly in ex-arable fields and semi-natural grasslands indicated that the main cause of difference in species assembly between them was difference in their age. The main conclusion of this thesis is that regional processes are more important than local factors in determining plant community assembly. / <p>At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 3: Submitted. Paper 4: Submitted. Paper 5: Manuscript.</p>

The success or failure of many organisms to respond to the challenges of habitat destruction and a warming climate lies in the ability of plant species to disperse between isolated habitats or to migrate to new ranges. European semi-natural grasslands represent one of the world's most species-rich habitats at small scales, but agricultural intensification during the 20th century has meant that many plant species are left only on small fragments of former habitat. It is important that these plants can disperse, both for the maintenance of existing populations, and for the colonisation of target species to restored grasslands. This thesis investigates the ecological, geographical and historical influences on seed dispersal and connectivity in semi-natural grasslands, and the mobility of plants through time and space. Seed dispersal by human activity has played a large role in the build-up of plant communities in rural landscapes, but patterns have shifted. Livestock are the most traditional, and probably the most capable seed dispersal vector in the landscape, but other dispersal methods may also be effective. Motor vehicles disperse seeds with similar traits to those dispersed by livestock, while 39% of valuable grasslands in southern Sweden are connected by the road network. Humans are found to disperse around one-third of available grassland species, including several protected and red-listed species, indicating that humans may have been valuable seed dispersers in the past when rural populations were larger. Past activities can also affect seed mobility in time through the seed bank, as seeds of grassland plant species are shown to remain in the soil even after the grassland had been abandoned. Today however, low seed rain in intensively grazed semi-natural grasslands indicates that seed production may be a limiting factor in allowing seeds to be dispersed in space through the landscape. / <p>At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 3: Accepted. Paper 4: In press. Paper 5: Manuscript.</p>

Resumo: O crambe (Crambe abyssinica Hochst) é uma planta da família Brassicaceae cujas sementes possuem elevado teor de óleo, sendo destinado no Brasil, principalmente, para a produção de biodiesel. É uma cultura que apresenta baixo custo de produção, seu cultivo é totalmente mecanizado com semedura no inverno e favorece a rotação com outras culturas de verão. No Brasil, a produção e a comercialização de sementes de crambe iniciaram-se há poucos anos, por isso estudos na área de tecnologia de produção são essenciais para obtenção de sementes de boa qualidade. Dentre os fatores que afetam a qualidade das sementes está o processo de secagem. A diminuição do teor de água das sementes em níveis adequados permite preservar as sementes por um período prolongado, possibilitando menor perda de vigor e germinação ao longo do armazenamento. O objetivo deste estudo foi avaliar o efeito de diferentes métodos de secagem sobre a qualidade de sementes de crambe no decorrer do armazenamento. O campo de produção de sementes de crambe foi instalado na Fazenda Experimental Lageado e os tratamentos experimentais foram conduzidos no Laboratório de Processamento de Produtos Agrícolas, pertencente ao Departamento de Engenharia Rural, e na Fazenda Experimental Lageado. As avaliações de qualidade foram realizadas no Laboratório de Análise de Sementes pertencente ao Departamento de Produção Vegetal - Setor Agricultura... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Crambe (Crambe abyssinica Hochst) is a member of the Brassicaceae family. Its seeds have high oil contents and its growth in Brazil aims to produce bio diesel. It is a low cost production and its cultivation is totally mechanized. It is also sowed at winter time, which favors crop rotation with other summer crops. In Brazil, Crambe seeds production and commercialization began a few years ago. The research in technology production is essential to obtain high quality seeds. Among the factors that affect seed quality there is the drying process. Seed water content decreased to an appropriate level allowing for a prolonged preservation time and enabling less vigor and germination loss during storage. The aim of this study was to evaluate the effect of different drying methods on Crambe seeds quality during storage. The seeds were produced in Fazenda Lageado, Faculdade de Ciências Agronômicas, UNESP, Botucatu / SP. Experimental treatments were conducted at Laboratório de Processamento de Produtos Agrícolas, Departamento de Engenharia Rural, and Fazenda Experimental Lageado. Evaluations on seed quality were conducted at Laboratório de Análise de Sementes, Departamento de Produção Vegetal - Setor Agricultura. Seeds were submitted to the following drying methods: a) seed drying in the shade with natural ventilation; b) artificial drying method using heated air; c) artificial drying method using unheated air; d) drying on ceramic patio; e) drying on the mother plant. Seeds were stored in laboratory conditions with bimonthly monitoring of their quality during a 8 month period. The following testes were performed: seed moisture content, standard germination test, first count of germination test, seedling emergence,emergence speed index and electrical conductivity. The accelerated ageing and seedling growth tests were performed on the 8th month of storage. The data obtained in each storage... (Complete abstract click electronic access below) / Orientador: Marco Antonio Martin Biaggioni / Coorientador: Cláudio Cavariani / Banca: Elza Alves / Banca: João Nakagawa / Mestre

Submitted by Neusa Fagundes (neusa.fagundes@unioeste.br) on 2017-09-25T14:47:50Z No. of bitstreams: 1 Davi_Rocha2017.pdf: 3573661 bytes, checksum: 8912d0785316cee5fdd46712b6f23d78 (MD5) / Made available in DSpace on 2017-09-25T14:47:50Z (GMT). No. of bitstreams: 1 Davi_Rocha2017.pdf: 3573661 bytes, checksum: 8912d0785316cee5fdd46712b6f23d78 (MD5) Previous issue date: 2016-12-07 / Fundação Araucária de Apoio ao Desenvolvimento Científico e Tecnológico do Estado do Paraná (FA) / Production and use of high quality seeds are important factors for the soybean farming. Therefore the quality control system in the seed industry must be reliable, accurate and fast. Seed technology research has been striving to develop or improve tests to enable seed quality evaluation. Tetrazolium test, besides evaluating the viability and vigor of the seeds, provides information about the potencial causing agents of quality reduction. Even though not using expensive instruments and reagents, the test requires a well-trained seed analyst, and the test’s accuracy depends on their knowledge about the all involved techniques and procedures, including the subjectivity of the observer. Therefore, the objective of the present research was to develop a computational tool that could minimize the implicit subjectivity in the test, contributing to increase information credibility and ensure the accuracy results. This tool allows, by tetrazolium test images, to identify seeds damage, as well as their location and extension, making the interpretation less subjective. From the feature extraction data in digital images of tetrazolium test, supervised classification algorithms were applied to do segmentation in the images, generating a classified image. The proposed system was tested using a selection of samples to training the classifier model and, from this model, the images classification of the tetrazolium test, to extract information about the seeds damage. The system allowed, in addition to an easier way for damages identification in the tetrazolium test images, the extraction of accurate information on displayed damage and achieve the control of the analyzed samples. The classifier performed the assignment of the predetermined categories efficiently for non-present data training set, with 96.6% of correctly classified instances and Kappa index of 0.95%, making the system a supplementary tool in decision making for the tetrazolium test. / A produção e a utilização de sementes de alta qualidade são fatores de importância para o cultivo da soja. Para isso, o sistema de controle de qualidade na indústria de sementes deve ser confiável, preciso e rápido. A pesquisa em tecnologia de sementes tem se esforçado em desenvolver ou aprimorar testes que possibilitem a avaliação da qualidade das sementes. O teste de tetrazólio, além de avaliar a viabilidade e o vigor de sementes, fornece informações sobre possíveis agentes causadores da redução de sua qualidade. Embora não se utilize de instrumentos e reagentes caros, o teste requer um analista de sementes bem treinado, sendo que a precisão do mesmo depende do conhecimento de todas as técnicas e procedimentos envolvidos, devendo-se considerar a subjetividade do observador. Sendo assim, o objetivo desta pesquisa foi desenvolver uma ferramenta computacional que minimizasse a subjetividade implícita na realização do teste, contribuindo para gerar maior credibilidade nas informações e garantindo precisão nos resultados. Esta ferramenta permite, a partir de imagens do teste de tetrazólio, realizar a identificação dos danos presentes nas sementes, bem como sua localização e sua extensão nos tecidos, tornando a interpretação menos subjetiva. A partir da extração de dados de características das imagens digitais do teste de tetrazólio, foram aplicados algoritmos de classificação supervisionada para realizar a segmentação destas imagens, produzindo uma imagem classificada. O sistema proposto foi testado utilizando a seleção de amostras para treino do modelo classificador e, a partir deste modelo, a classificação das imagens do teste de tetrazólio, para extração de informações sobre os danos verificados nas sementes. O sistema permitiu, além da identificação dos danos nas imagens do teste de tetrazólio de forma facilitada, a extração de informações mais seguras sobre os danos presentes e realizar o controle das amostras analisadas. O classificador realizou a atribuição das classes predeterminadas de forma eficiente para dados não presentes no conjunto de treinamento, com 96,6% de instâncias classificadas corretamente e Índice Kappa de 0,95%, tornando o sistema uma ferramenta suplementar na tomada de decisão para o teste de tetrazólio.

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