Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico / The purpose of this thesis was to investigate the feasibility of using the honey bee (Apis mellifera L.) for pollination and yield increment in Jatropha curcas L. crops. Therefore, the floral biology and pollination process of J. curcas were studied as well as the foraging behavior and pollination efficiency of A. mellifera in this crop by the introduction of four colonies in a hectare. The work was carried out in a five years-old commercial plantation comprising 10ha, in the state of PiauÃ, (08Â32â19,0âS and 43Â56â19,7âW, 220 meters above sea level), Brazil, from March to July, 2009. Flowers were presented in protogynous inflorescences and the anthesis and most of pollen presentation took place mainly in the morning shift. Inflorescences last, in average, 20 days, with female flowers concentrating in the first third of the period and male flowers predominating in the second third, in a relation of 18.1:1 male/ female flower. Although this may favor xenogamy, the stigma receptivity lasts for, at least, five days ensuring the flower to reach the period of most pollen release in its own inflorescence, facilitating the occurrence of geitonogamy. Flowers pollinated up to four days after anthesis did not differ (p>0.05) in fruit setting to those pollinated in the first, second or third day after anthesis. Foraging by A. mellifera occurs throughout the day and peaks between 13h00min and 15h00min and is characteristic of nectar harvesting both in male and female flowers. Only one visit by A. mellifera to J. curcas flowers set 100% producing results similar (p>0,05) to those from manual xenogamy (96%), manual geitonogamy (94%) and open pollination (93%). However, only one visit by a bee was not enough to maximize the oil content per seed (213mg) in comparison to the open pollination and geitonogamy treatments (both 250mg). Besides that, it was possible to observe that geitonogamy led to greater oil production than xenogamy (237mg). It is concluded that A. mellifera is an efficient pollinator of this crop. The introduction of four honey bee colonies per hectare maximize oil production and produce the best results for all parameters studied. Furthermore, only one visit by the honey bee to J. curcas flowers was enough to prevent pollination deficit in this crop. / O objetivo desta tese foi investigar a possibilidade da utilizaÃÃo de Apis mellifera L. na polinizaÃÃo e incremento de produtividade da cultura do pinhÃo manso (Jatropha curcas L.). Para tanto, foi estudado a biologia floral e a polinizaÃÃo do pinhÃo manso bem como o comportamento forrageiro e a eficiÃncia polinizadora de Apis mellifera. O trabalho foi realizado em 10ha de plantio comercial jà estabelecido, com cinco anos de idade, no estado do PiauÃ, (08Â32â19,0âS e 43Â56â19,7âW e 220 metros de altitude), entre os meses de marÃo e julho de 2009. A antese das flores do pinhÃo manso, distribuÃdas em cimos com carÃter protogÃnico, ocorre basicamente no perÃodo matinal, bem como a maior oferta de pÃlen. As inflorescÃncias duram, em mÃdia, 20 dias, com maior concentraÃÃo de flores femininas no terÃo inicial e de masculinas, no terÃo mÃdio, com relaÃÃo de 18,1 flores masculinas para cada feminina. Embora esse fato favoreÃa a xenogamia, a receptividade do estigma por, pelo menos, cinco dias, garante a flor alcanÃar o perÃodo de maior oferta de pÃlen no prÃprio cimo, oportunizando a geitonogamia. As flores polinizadas atà o quarto dia frutificam da mesma forma que aquelas polinizadas no primeiro, segundo e terceiro dias apÃs antese, nÃo havendo diferenÃas significativas. O forrageamento por A. mellifera ocorre durante todo o dia, com maior pico entre 13h00m e 15h00m e à tÃpico de coleta de nÃctar, tanto nas flores masculinas quanto nas femininas. Apenas uma visita da abelha Ãs flores acarreta em 100% de vingamento, mostrando resultado semelhante, (p>0,05), aos tratamentos de xenogamia manual (96%), geitonogamia manual (94%), e polinizaÃÃo aberta (93%). PorÃm, uma visita apenas, nÃo à suficiente para produzir maior quantidade de Ãleo por semente (213mg), em comparaÃÃo com o tratamento de polinizaÃÃo aberta, e por geitonogamia (250mg). AlÃm disto, foi possÃvel constatar que hà maior produÃÃo de Ãleo por geitonogamia e nÃo por xenogamia (237mg). Conclui-se que a Apis mellifera à um polinizador eficiente da cultura. Sua introduÃÃo, com quatro colÃnias por hectare, maximiza a produÃÃo de Ãleo e produz os melhores resultados para todos os parÃmetros avaliados. AlÃm disso, apenas uma visita da abelha melÃfera Ãs flores do pinhÃo manso à suficiente para prevenir dÃficit de polinizaÃÃo.

Uma das técnicas de restauração ecológica de vegetação nativa testada é a semeadura direta ou plantio de sementes, que pode diminuir custos, facilitar a implantação e a adaptação rápida da espécie ao ambiente comparando ao plantio de mudas. Porém, essa técnica não suplantou o plantio de mudas e um dos questionamentos é sobre abaixa germinação das sementes e do desconhecimento das práticas adequadas de semeio. Portanto, nessa pesquisa avaliaram-se a qualidade, características e desempenho de sementes de cinco espécies florestais nativas, testando também algumas técnicas de semeio no campo. As sementes utilizadas são de espécies arbóreas de recobrimento: Croton floribundus, Croton urucurana, Guazuma ulmifolia, Solanum granulosoleprosum e Trema micrantha de dois lotes (um comprado no mercado e outro colhido pelo pesquisador no campo).A qualidade dessas sementes foi determinada por meio dos parâmetros físicos: pureza, teor de água, massa de mil sementes, largura, comprimento, área, circularidade, cor (sistemas RGB e banda G), peso e densidade aparente; fisiológicos: a velocidade e a taxa de emergência das plântulas e sanitário: avaliação dos fungos presentes nas sementes. Métodos para o beneficiamento dos lotes de sementes, a partir dos parâmetros físicos foram testados. E foram avaliadas a profundidade de semeadura e a emergência das plântulas das sementes tratadas e não-tratadas através do priming, testados em laboratório e em campo. A caracterização física dos lotes (comprado e colhido) foi semelhante (pureza e teor de água), as outras medidas físicas foram em geral diferentes entre os lotes e geralmente maiores para o lote colhido, e apenas para a G. ulmifolia o lote comprado foi superior. Fisiologicamente, os lotes (comprado e colhido) foram similares, porém o lote de G. ulmifolia comprado e de T. micrantha colhido emergiram mais, e as demais espécies foram semelhantes. O mesmo pode-se afirmar para o índice de velocidade de emergência das plântulas (IVEP), que também foram semelhantes entre os lotes, mas não para TMEP (Tempo Médio de Emergências das Plântulas). Para sanidade, os lotes colhidos obtiveram menor incidência de fungos fitopatogênicos. A densidade aparente foi a variável mais correlacionada com a emergência das sementes. Já as melhores profundidades de semeadura foram de 1 cm para a S. granulosoleprosum, 2 cm para a G. ulmifolia e de 1-2 cm para as demais espécies. O priming foi significativo, em laboratório, para C. floribundus em emergência, IVEP e TMEP, e T. micrantha em IVEP. Em campo, o priming reduziu o TMEP de C. floribundus e de T. micrantha, e melhorou o IVEP desta. As espécies mais recomendadas para semeadura direta a partir da emergência em campo são: S. granulosoleprosum >C. floribundus >G. ulmifolia >C. urucurana >T. micrantha. O monitoramento de emergência das plântulas pode ser realizado em 50 dias para S. granulosoleprosum, 65 dias para T. micrantha e 30 dias para as demais. Concluem-se que os lotes (comprados ou colhidos) são adequados, o uso da densidade aparente é o melhor método de beneficiamento e não houve benefícios significativos com o priming. Essas práticas podem ser empregadas em semeadura direta em restauração ecológica. / One of ecological restoration techniques for native vegetation tested is the direct sowing or planting seeds, which can lower costs, easy deployment and rapid adaptation of species to the environment compared to planting seedlings. However, this technique does not supplanted the planting of seedlings and one of the questions is on the low germination of native species and the lack of best practices of sowing. Therefore, in this study it was evaluated the quality, features and performance of five native species seeds, also testing some sowing techniques in the field. The seeds used were tree species filling, Croton floribundus, Croton urucurana, Guazuma ulmifolia, Solanum granulosoleprosum and Trema micrantha two lots (one purchased in the market and another collected by the researcher in the field). The quality of these seeds was determined by the physical parameters: purity, water content, mass of thousand seeds, width, length, area, roundness, color (RGB systems and G band), weight and specific gravity; Physiological: the speed and the emergence rate of seedlings and health: assessment of fungi present in the seeds. Methods for processing of seed lots, from the physical parameters had tested. And it evaluated the depth of sowing and seedling emergence of seeds treated and non-treated by priming, tested in laboratory and on field. Physical characteristics of the lots (purchased and harvested) was similar (purity and water content), other physical measurements were generally different between lots and generally larger for the lot harvested, and only for the G. ulmifolia purchased lot was higher. Physiologically, lots (purchased and harvested) were similar, but G. ulmifolia purchased lot emerged more and T. micrantha harvested lot was better, and the other species were similar. The same said for the seedling emergence speed index (SESI), which were also similar between lots, but not for MTES (Mean Time Emergencies of Seedlings). For sanity, lots harvested was lower incidence of pathogenic fungi. The specific gravity was the most correlated variable with the emergence of seeds. Already the best sowing depths were 1 cm for S. granulosoleprosum, 2 cm to G. ulmifolia and 1-2 cm for other species. The priming was significant in the laboratory for C. floribundus in emergency, SESI and MTES, and T. micrantha in SESI. In the field, the priming reduced the MTES for C. floribundus and T. micrantha, and improved SESI this. The most recommended species for direct sowing on field in emergency are: S. granulosoleprosum>C. floribundus>G. ulmifolia>C. urucurana>T. micrantha. The emergency monitoring of seedlings can be done in 50 days for S. granulosoleprosum, 65 days for T. micrantha and 30 days for the other. To conclude that lots (purchased or harvested) are suitable, the use of the specific gravity is the best processing method and no significant benefits with priming. These practices may be employment in direct sowing in ecological restoration.

Made available in DSpace on 2014-08-20T13:44:29Z (GMT). No. of bitstreams: 1 dissertacao_ronaldo_joao_vendrame.pdf: 206490 bytes, checksum: 8d8cd3ea0bba575c008d09b380c19b64 (MD5) Previous issue date: 2012-10-17 / This study aimed to evaluate the relationship among seed size and their physical and physiological attributes in three soybean cultivars (NK 7059 RR, SYN 3358 RR and BMX POTÊNCIA RR). Samples were collected from the Seed Processing Unit C.Vale in Abelardo Luz-SC, and the following analyzes were performed: seed germination , seed vigor, mechanical damage, screen retention and weight of 1000 seeds. The analyzes were performed at the Laboratory of Seeds Analysis C.Vale- Cooperativa Agroindustrial in Palotina-PR, and the following cultivars and screens were used: NK 7059 RR (5.75 and 6.75 mm), SYN 3358 RR (5.5 and 6.5mm) and BMX POTÊNCIA RR (5.75 and 6.75mm). The analysis of seed germination was performed according to the Brazilian Rules for Seed Analysis; the seed vigor test was based on the accelerated aging and the test with sodium hypochlorite was used for the evaluation of mechanical damage. Two replicates of 100 seeds were used for the screen retention test, which was determined by retention in specified screen and in screen without perforations. The weight of 1000 seeds was measured in eight replications of 100 seeds. The following conclusions were obtained: 1-Physiological seed quality is independent of seed size 2-There is higher seed retention on the superior screen, reaching more than 10%, and 3-Large seeds tend to have higher mechanical damage. / O presente trabalho teve como objetivo avaliar a relação do tamanho das sementes de soja em três cultivares (NK 7059 RR, SYN 3358 RR e BMX POTÊNCIA RR), sobre os atributos físicos e fisiológicos da semente na qualidade das sementes. As amostras foram coletadas da Unidade de Beneficiamento Sementes da C.Vale, em Abelardo Luz-SC, sendo feito as seguintes análises: Germinação, Vigor, Dano mecânico, Retenção de peneiras e peso de mil sementes. As análises foram conduzidas no Laboratório de Análise de Sementes da C.Vale-Cooperativa Agroindustrial, em Palotina-PR, para os seguintes cultivares e peneiras: NK 7059 RR(5,75 e 6,75), SYN 3358 RR(5,5 e 6,5) e BMX POTÊNCIA RR(5,75 e 6,75). A análise de germinação seguiu as normas da Regra de Análise de Sementes; A análise de vigor foi feita com base no Teste de Envelhecimento Acelerado e a avaliação do dano mecânico foi feita aplicando-se o teste com hipoclorito de sódio. A retenção de peneiras foi determinada através da retenção na peneira especificada em duas repetições de 100 sementes e outra peneira com um fundo cego. Por último, foi determinado o peso de 1000 sementes com oito repetições com 100 sementes de cada. As seguintes conclusões foram obtidas: 1 A qualidade fisiológica independe do tamanho das sementes; 2 Há uma maior retenção de sementes na peneira superior, podendo alcançar mais de 10%; e 3 As sementes grandes tendem a apresentar maior danificação mecânica.

Made available in DSpace on 2014-08-20T13:44:32Z (GMT). No. of bitstreams: 1 dissertacao_mario_flavio_magalhaes.pdf: 390698 bytes, checksum: b63a52591a132180ce56f1e7d631a56b (MD5) Previous issue date: 2012-12-18 / The products to be applied in seed treatment must provide sufficient protection to both seed and seedlings in the field, keeping the fungi, insects and nematodes properly controlled. The aim of this study was to evaluate the possible immediate and latent effect of the product Avicta Complete (fungicide, insecticide and nematicide), Cruiser 350 FS + Maxim Advanced and Maxim Advanced on the physiological quality of hybrid maize seed. We used seven hybrids from Monsanto: DKB 330, DKB 350, DKB 390, AG 7000, AG 8021, AG 8015 and AG 9010. Seeds were subjected to the following treatments 1) Control, 2) Avicta Complete®, 3) Cruiser 350 FS® + Maxim advanced®, 4) Maxim Advanced®, and then stored at room temperature for up to 360 days. The assessments were made at 45, 90, 180 and 360 days, and the attributes evaluated were: germination, accelerated aging, speed of emergence and cold test. The data was analyzed according to statistical analysis on the effect of isolated products and the interaction treatment/storage in which the following conclusions were obtained: 1) The treatment on the seeds varies according to the hybrid; 2) In general the phytotoxic effect of the seed treatment is detected after 90 days in ambient storage of the seeds; 3) The fungicide Maxim Advanced did not result in any phytotoxic effect in the hybrids during storage in a not climacteric environment and 4) Corn seed storage for 360 days at cold conditions and treated with Avicta completo and Cruiser plus Maxim Advanced, remain with high physiological quality. / Os produtos a serem aplicados no tratamento de sementes devem oferecer proteção suficiente tanto às sementes como às plântulas no campo, mantendo os fungos, insetos e nematóides devidamente controlados. O objetivo do presente trabalho foi verificar o possível efeito imediato e latente do produto Avicta Completo (ação fungicida, inseticida e nematicida), Cruiser 350 FS + Maxim Advanced e Maxim Advanced sobre a qualidade fisiológica de sementes de milho híbrido. Foram utilizados sete híbridos da empresa Monsanto: DKB 330, DKB 350, DKB 390, AG 7000, AG 8021, AG 8015 e AG 9010. As sementes foram submetidas aos seguintes tratamentos: 1) testemunha, 2) Avicta Completo ®, 3) Cruiser 350 FS® + Maxim Advanced®, 4) Maxim Advanced®, sendo então armazenadas em temperatura ambiente por até 360 dias. As avaliações foram feitas aos 45, 90, 180 e 360 dias, com as seguintes características avaliadas: germinação, envelhecimento acelerado, índice de velocidade de emergência e teste de frio. Os dados foram discutidos conforme análise estatística sobre o efeito isolado dos produtos e a interação tratamento/armazenamento no qual se obtiveram as seguintes conclusões: 1) o efeito do tratamento de sementes varia entre híbridos de milho em condições ambientais; 2) em geral, os efeitos fitotóxicos dos tratamentos em sementes manifestam-se a partir dos 90 dias de armazenamento, em condições ambientais; 3) O fungicida Maxim Advanced testado não apresentou efeito fitotoxico aos híbridos durante o armazenamento em ambiente não climatizado e 4) sementes de milho híbrido armazenadas por 360 dias em condições climatizadas e tratadas com Avicta completo e Cruiser mais Maxim Advanced, permanecem com alta qualidade fisiológica.

Made available in DSpace on 2014-08-20T13:44:34Z (GMT). No. of bitstreams: 1 dissertacao_adhemar_antonio_de_oliveira_junior.pdf: 235690 bytes, checksum: fdf540bfb4ba71eeef37d73bd6b35be8 (MD5) Previous issue date: 2012-12-18 / The products to be applied in the disinfestation of seed shall provide sufficient protection to seed as much as the seedlings in the field, keeping the fungi, insects and nematodes properly controlled. The objective of this study was to investigate the possible effect immediate and latent product Avicta Complete® Pack (with fungicide, insecticide and nematicide action) on the physiological quality of hybrid maize seed. Was used six hybrids from Pioneer Company: 30K73, 30F35, 30F80, 30K75, 30R50 and 32R22. The seeds were submitted to the following health treatments: 1) control, 2) Avicta Complete®, 3) overdose Avicta Complete® 100%, and then stored at room temperature and cold chamber (100 C and 60% RH) for 350 days. The evaluations were performed at 50, 150, 250 and 350 days, and the characteristics evaluated: germination, cold test and accelerated aging. Assays were performed at the Laboratory of Seeds of Tropical Breeding and Genetics Company and the data were subjected to statistical analysis using the statistical program Sisvar® (FERREIRA, 2000). Data were analyzed according to statistical analysis on the isolated effect of the products and environment interaction / storage in which we obtained the following conclusions: the reduction of the physiological quality of corn seeds varied depending on the treatment of the hybrid and the time that seeds remain stored after treatment and the reduction of physiological seed quality intensified with prolonged storage of the treated seed, it is validating therefore the secure processing and storage Avicta Complete® Pack with up to 250 days, which helps the management of treatment on seed processing units in Seed Corn Companies. / Os produtos a serem aplicados no tratamento sanitário de sementes devem oferecer proteção suficiente tanto às sementes como às plântulas no campo, mantendo os fungos, insetos e nematóides devidamente controlados. O objetivo do presente trabalho foi verificar o possível efeito imediato e latente do produto Avicta Completo (ação fungicida, inseticida e nematicida) sobre a qualidade fisiológica de sementes de milho híbrido. Foram utilizandos seis híbridos da empresa Pioneer: 30K73; 30F35; 30F80; 30K75; 30R50 e 32R22. As sementes foram submetidas aos seguintes tratamentos sanitários: 1) testemunha, 2) Avicta Completo®, 3) Superdosagem de Avicta Completo® 100%, sendo então armazenadas em temperatura ambiente e câmara fria(10oC e 60% de Umidade Relativa) por 350 dias. As avaliações foram feitas aos 50, 150, 250 e 350 dias, sendo as características avaliadas: germinação, teste de frio e envelhecimento acelerado. Os ensaios foram realizados no Laboratório de Sementes da empresa Tropical Melhoramento e Genética e os dados foram submetidos à análise estatística, utilizando-se o programa estatístico Sisvar® (FERREIRA, 2000). Os dados foram discutidos conforme análise estatística sobre o efeito isolado dos produtos e a interação ambiente/armazenamento no qual se obteve as seguintes conclusões: A redução da qualidade fisiológica de sementes de milho variou em função do tratamento, do híbrido e do tempo em que as sementes permaneceram armazenadas após o tratamento e a redução da qualidade fisiológica das sementes intensificou-se com prolongamento do armazenamento das sementes tratadas, validando, portanto, a segurança do tratamento e armazenamento com Avicta Completo até 250 dias, o que ajuda ao gerenciamento do tratamento nas unidades de beneficiamento de sementes das empresas produtoras de sementes de milho.

Il rinnovato interesse nella coltivazione della canapa industriale non è stato supportato da studi approfonditi e generalmente si basa su esperienze dirette di coltivazione. Questo studio si prefigge come obbiettivo quello di sfruttare tutte la parti della pianta di canapa per migliorare l’economicità complessiva della sua coltivazione tramite l’uso di tecniche agronomiche e di pratiche post-raccolta. La Cannabis sativa ha un vasto campo di applicazioni, tra cui le più promettenti in termini di ritorno economico sono il cosmetico e il farmaceutico. I composti naturali più interessanti della Cannabis sono i cannabinoidi non-psicoattivi cannabidiolo (CBD) e cannabigerolo (CBG) presenti in elevate concentrazioni nelle foglie e nelle brattee di Cannabis. Altri metaboliti secondari prodotti dalla canapa e di grande interesse sono le cannflavine, una classe di prenil-flavonoidi caratteristico di questa specie. Nel primo e nel secondo capitolo la dinamica temporale di accumulo dei metaboliti secondari ad elevato valore aggiunto è stata monitorata per alcune delle varietà più comuni di canapa industriale ed è stata determinata la produzione potenziale di questi composti. Nel terzo capitolo una collezione di semi di canapa è stata valutata per le caratteristiche morfologiche e per il contenuto e la qualità dell’olio. Concludendo questo studio contribuisce allo sviluppo di una coltivazione della canapa per le molteplici destinazioni d’uso dei semi e del fitocomplesso. / Rapidly growing interest into industrial hemp cultivation is not supported by strong data and generally is referred to a limited experience on field cultivation. This study aims to exploit all the parts of hemp plant, in order to ameliorate the overall economy of its cultivation and by providing information on agronomic management and post-harvest operations. Cannabis sativa has a wide range of industrial applications and the most promising, in terms of economic revenues, are the cosmetic and pharmaceutics. The most interesting phytochemicals in Cannabis are the cannabinoids, in particular the non-intoxicating compounds cannabidiol (CBD) and cannabigerol (CBG), present at high concentration in the leaves and bracts of Cannabis. Some other promising secondary metabolites of hemp are cannflavins, a class of prenyl-flavonoids characteristic of this species. In the first and second chapter the time course accumulation of high added-value compounds was monitored for some of the most common industrial hemp cultivars, and the potential production was assessed. In the third chapter a collection of hemp seeds was evaluated for its morphological characteristics and for its oil content and quality. In conclusion this thesis contributes to a further development of multipurpose hemp cultivation for seed and phytocomplex production.

The time when the seed germinates is very important. Ability to change the time of germination may be very advantageous. It allows the emerging seed to choose the best time according to abiotic conditions, and also to avoid of competition with neighbouring individuals. The seed reacts not only on adult plants and seedlings, but also on other seeds, with which is able to communicate. For a better understanding to this mechanism I conducted an experimental study with twenty-six species. The species were selected according to their position in long succession seres of mesic/xeric abandoned fields in Český kras. The seeds were left to germinate in pairs in all combinations among them. Here I present the results where I show how the time of emergence changes, depending on presence of neighbouring seed. Also, I show how these changes in germination are related to species specific traits. Out of this, I tried to influence communication between seeds by adding activated carbon. Activated carbon should stop the communication by highly absorbing surface. The time of germination of seeds which germinated alone was not proportional to the time of germination of seeds which germinated with neighbours. This correlation showed up like nonlinear, late-emerging seeds emerging unproportionally later when emerging...

The bulk of Zimbabwe’s groundnut (Arachis hypogaea L.) crop is grown on sandy soils in the smallholder sector where sustainable production is hindered by acid soil infertility. The study goal was thus to examine the effects of soil acidity amelioration by four Ca-containing materials on nutrient composition, vegetative and reproductive growth, and quality of groundnut to formulate ameliorative strategies to improve productivity on acid soils. The effectiveness of calcitic lime (CL), dolomitic lime (DL), gypsum (G) and single superphosphate (SSP) in ameliorating soil acidity was determined in field experiments conducted for three seasons at two Research Stations in Zimbabwe, and in greenhouse experiments conducted for two seasons at Harare Research Station. In both experiments the lime application rates were from 0 to 4000 kg ha-1, while G application rates were from 0 to 3450 kg ha-1, and those of SSP were from 0 to 250 kg ha-1. Calcitic or dolomitic lime applied at 2000 or 4000 kg ha-1 increased soil pH and Ca and Mg contents in the pod and root zones, and in the plant material. Gypsum and SSP applications at 200 and 250 kg ha-1 respectively, had no significant effects on pH, Ca and Mg levels, but when applied in equivalent amounts of Ca as lime, gypsum improved soil Ca status. Effects of the four ameliorants on the N, P and K levels in the soils and in plant material were generally neither significant nor consistent. The direct and residual benefits of application of CL or DL were manifested in improved plant stands, better growth, nodulation, productivity and quality of groundnut. Gypsum applied at equal Ca rates as CL or DL was the superior Ca-source in improving pod and kernel quality. By the end of the third season, the increases in cumulative kernel yields due to application of 4000 kg ha-1 lime over non-application were up to 319%. The major growth-limiting factors on the studied acid soils were identified as deficiencies of Ca and Mg, and low pH per se. In a field experiment conducted to evaluate the tolerance of 15 groundnut genotypes to soil acidity, significant differences in yield and nutrient utilization efficiency of the genotypes were observed, implying that productivity on acid soils can be increased by growing genotypes efficient in uptake and utilization of nutrients. Results from greenhouse and growth chamber studies conducted to examine the effects of pH (3.0 - 7.0) and its interactions with Ca (0 - 2000 µM Ca) on early seedling growth and reproductive growth of groundnut indicated that low pH per se has a major detrimental impact on seedling survival, growth, pod formation, yield and quality of groundnut, but not on germination. The adverse effects of low pH were more pronounced in the absence of Ca, and became progressively less as the solution Ca concentrations increased. Further experiments showed that it is feasible to mitigate the adverse effects of soil acidity on groundnut germination and seedling survival by pelleting seeds with small amounts of CaCO3, or priming with CaSO4. / Dissertation (PhD (Plant Production: Agronomy))--University of Pretoria, 2003. / Plant Production and Soil Science / unrestricted

The goal of this thesis is to identify the challenges and success factors of the support system for innovative start-ups in the Czech Republic as well as to formulate recommendations for the implementation of the currently envisaged Seed fund project. The thesis covers the specifics of start-up companies and barriers for their development and puts them in relation with the current state of the Czech entrepreneurial environment and its innovation performance. Hard data as well as opinions of experts and potential investors are assessed to analyze the needs and motivations of both demand and supply sides of the venture capital market in order to provide some valuable insights which may help the support system to improve the access of entrepreneurs to external finance and boost the creation of innovative start-ups in the Czech Republic. The main suggestions introduced relate to the focus on retaining strict transparency, to the careful selection of entities evaluating the viability of projects and those providing services assisting the entrepreneurs in the preparation phase. Finally, the right setting of conditions of the Seed fund to attract both private investors and entrepreneurs will determine the success of the whole project.

Farmer-led seed systems (FSS) provide the backbone for small-scale farmers and many rural communities that use traditional methods of farming to produce seeds that grow and adapt to local conditions. FSS differ from one community and farmer to the next, depending on the methods and practices used to maintain seed varieties. Seed diversity can enhance FSS by improving livelihoods and strengthening farmers' networks, thus contributing to resilient communities. Although nuanced, the dualistic agricultural system in South Africa consists largely of subsistence (small-scale) and commercial (large-scale) farming and includes different crop management systems and post-harvest practices. In South Africa, maize (Zea mays) is a major staple grain crop with a significant role as animal and poultry feed. The North West region is one of the highest white-maize-producing provinces in South Africa. Maize seed systems include both traditional, openpollinated varieties (OPVs) and cultivars such as modern hybrids and genetically modified (GM) seed varieties, including those engineered for specific purposes. The dominant GM maize is that designated for pest resistance using Bacillus thuringienesis (Bt), a soil bacterium which produces a toxin that is fatal to a wide variety of insects such as moths and flies. Many small-scale farmers prefer their own traditional seeds for breeding, planting, selection, selling and consuming. However, FSS based on traditional varieties are threatened by modern cultivars which may be introduced in different ways including through seed exchange, purchasing at shops or by pollination from nearby commercial farms. This study was conducted in the Sespond community of the North West Province. The aim of the study was to understand how small-scale farmers in Sespond maintain traditional maize varieties through selection and storage in a complex agricultural landscape that incorporates both formal and informal seed systems. The formal system represents industrialised farms and companies that work with commercial seed. The informal system represents small-scale farmers who rely on their own seed. Qualitative methods included mapping software which was used to obtain visual agricultural data in and around Sespond. Semi-structured interviews were conducted with 30 small-scale farmers to collect information about their farming practices, including the maize varieties planted. Quantitative methods included collecting 20 maize samples from different farmers for genetic analysis. Agdia® immunostrip tests were used to detect for the presence of Crystal protein (Cry protein) produced by the Bt bacterium, engineered to improve the resistance of maize against insects. The results showed that 13 samples were negative for the protein and seven samples were positive for the protein. A key finding is that small-scale farmers are not able to detect the different maize varieties in their seed systems. This represents a threat for traditional seed varieties in the community as without this knowledge, farmers are not able to adequately manage their production and storage systems. Farmers made use of alternative storage methods such as the mill to reduce seed damage they experienced at home. However, the findings of this research showed that there was an increasing risk of farmers' traditional maize being mixed with GM maize at the mill. Farmers' rights to plant and consume traditional maize were therefore undermined. This study recommends that (a) efforts are made to increase awareness among farmers that help to distinguish transgenes from hybrids and traditional maize varieties; (b) measures are implemented at mills to both improve the transparency about the storage and processing of traditional maize and to separate traditional maize from hybrid and GM maize.