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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Improving Snap Bean (Phaseolus vulgaris L.) Production under Reduced Input Systems

2015 October 1900 (has links)
Snap bean (Phaseolus vulgaris L.) production by large scale commercial producers in Ethiopia is under intensive production and relies on high rates of nitrogen (N) fertilizer and irrigation during the dry season. Despite increasing interest to produce this crop, small scale farmers cannot afford the high cost of N fertilizer. Field and greenhouse experiments were conducted to test snap bean production under a low input production system better suited to small scale resource limited farmers. Field experiments were conducted in 2011 and 2012 under rain fed conditions, and in 2012 under irrigation, at three locations (Debre Zeit, Hawassa, Ziway) representing different climate zones in Ethiopia. This experiment used three N treatments: 0 and 100 kg N ha-1, and inoculation with Rhizobium etli [HB 429], and eight cultivars: Andante, Boston Contender Blue, Lomami, Melkassa 1, Melkassa 3, Paulista and Volta. The general objective of the field experiment was to determine the potential of snap bean production under a low input production system using rhizobium inoculation as the nitrogen source, and use rain fed conditions. Results obtained indicated that rhizobial inoculation and applied inorganic N increased on average the marketable pod yield of snap bean under rain fed conditions by 18 % and 43%, respectively. Nodulation and subsequent N2 fixation was not effective in improving yield or other traits of snap bean pod under irrigation, although applied N increased marketable yield by 33%. Melkassa 1 was the most suitable cultivar for a reduced input production system due to its successful nodulation characteristics, greatest N2 fixation levels and consistently good performance across locations under rain fed conditions. Commercial cultivars possessed the best pod quality characteristics and they yielded better under irrigation. Cultivars interacted with locations to affect pod traits including total soluble solids and concentrations of protein, calcium, and potassium under rain fed conditions. Snap bean cultivrs produced at Debre Zeit and Hawassa were similar in marketable yield and several other traits particularly under rain fed conditions. Zinc (Zn) concentration in pods was greatest at Hawassa both under rain fed and irrigated conditions. Conditions at Debre Zeit were the most conducive for supporting biological N2 fixation for snap bean production. The eight cultivars were also used for a greenhouse study that was evaluated treatments of drought stress of 50% field capacity (50% FC) during the vegetative (V4.4), flowering (R6) and pod formation (R7) developmental stages. Our result showed that drought stresses during reproductive stages (R6 and R7) were the most sensitive stages in deteriorating the quality of snap bean pods. Drought stress increased protein, phosphorus and Zn concentrations but it reduced iron concentration in snap bean pods. All cultivars had a similar response to drought stress. A second greenhouse experiment was conducted to test foliar application of growth regulators: the control, 10-5 M and 10-4 M concentrations of each of abscisic acid (ABA), kinetin and salicylic acid (SA); and two concentrations of yeast extract (4 g l-1 and 8 g l-1), under drought (50% FC) stressed and unstressed conditions. Foliar application of SA on snap bean under greenhouse conditions reduced the impact of drought stress, particularly the pod quality parameters: marketable yield, pod curving, texture and appearance of snap bean pods. However, application of ABA, kinetin and SA reduced pod quality of snap bean under unstressed conditions. In conclusion, pod yield improvement could be achieved by a N2 fixation system under rain fed conditions, which is more sustainable than N fertilizer inputs. Pod quality was also adequate for commercial export production. Rhizobium inoculant can therefore be used as an alternative N source, particularly under low input production system for resource-limited small-scale snap bean producers.
2

Aperfeiçoamento do processo de fermentação láctica em diferentes hortaliças e avaliação de aspectos econômicos e energéticos

Goldoni, Cristiano Lima [UNESP] 17 June 2004 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:24:41Z (GMT). No. of bitstreams: 0 Previous issue date: 2004-06-17Bitstream added on 2014-06-13T20:12:49Z : No. of bitstreams: 1 goldoni_cl_me_botfca.pdf: 427201 bytes, checksum: 7b38b47366f9373e350359048f3fcfd3 (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Universidade Estadual Paulista (UNESP) / No presente trabalho estudou-se o comportamento das hortaliças couve-flor e feijão-vagem, submetidas ao processo de fermentação lática controlada sob temperatura de 20 C (variação de 0,5 C). O experimento constituiu-se de três ensaios de fermentação para cada uma das hortaliças: Tratamento Controle (Testemunha), Tratamento com Adição de Inóculo Comercial e Tratamento com Adição de Inóculo Comercial + Adição de Acido Lático. O monitoramento das fermentações foi realizado por meio de análises químicas, físicas, físico-químicas e microbiológicas, no decorrer e no final do processo fermentativo. Para a avaliação sensorial foram elaborados picles em vinagre de vinho branco condimentado, utilizando-se dos produtos fermentados e a matéria-prima in natura'. A pesquisa foi complementada com o estudo do gasto de energia elétrica e do custo de elaboração dos produtos fermentados, considerando-se o processamento em laboratório; e foi determinado o consumo de energia e sua racionalização, comparando-se com o armazenamento refrigerado (processamento mínimo) das diferentes hortaliças em estudo. Os resultados obtidos através das análises químicas, físico-químicas e microbiológicas, permitiram verificar que as fermentações transcorreram normalmente, obtendo-se produtos com características desejáveis, ou seja, de alimento fermentado e produzidos com as condições tecnológicas para se apresentaram seguros, em relação aos aspectos de conservação e de saúde pública. Para ambas as hortaliças estudadas (couve-flor e feijão-vagem), os tratamentos em que houve Adição de Inóculo Comercial, resultaram em produtos com níveis mais elevados de acidez. Para couve-flor a maior acidez foi desenvolvida no tratamento com Adição de Inóculo Comercial;... / In the present work it was studied the behavior of the vegetables cauliflower and snap-bean, submitted to the process of controlled lactic acid fermentation under temperature of 20 °C (variation of l 0,5 °C). The experiment was constituted for three trials of fermentation process for each one of the vegetables: Control Treatment (test) with Addition of Starter (Lactobacillus plantarum) and with Addition of Starter (L. plantarum) + Lactic Acid. The monitoring of the fermentations was accomplished through chemical, physical, physical-chemical and microbiological analyses, during and at the end of the fermentation process. Using the fermented products and raw vegetable, pickles were elaborated in spiced white vinegar for the purpose of sensorial evaluation. Parallelly, the research was complemented with the study of the expense of electric energy and the elaboration cost of the fermented products, being considered the processing in laboratory; and also, it was verified of the consumption of energy and its rationalization, being compared with the refrigerated storage (minimum processing) of the different vegetables in study. The obtained results through the chemical, physical-chemical and microbiological analyses, allowed to verify that the fermentations usually elapsed, being obtained products with desirable characteristics, that is to say, of fermented food and produced with the technological conditions for they came safe, in relation to the conservation aspects and of public health. For both studied vegetables (cauliflower and snap-bean), the treatments in that there were Addition of Starter, they resulted in products with a higher acidity levels. For cauliflower the greatest acidity was developed in the treatment with Addition of Starter;...(Complete abstract click electronic access below)
3

Bean Leaf Beetle: Impact of Leaf Feeding Injury on Snap Beans, Host Plant Choice and Role as a Vector of Bean Pod Mottle Virus in Virginia

Cassell, Meredith Edana 08 June 2011 (has links)
The bean leaf beetle (BLB), Cerotoma trifurcata (Forster) (Coleoptera: Chrysomelidae), is a pest of commercially produced legumes in eastern Virginia. Field cage and manual-defoliation studies were conducted in Virginia to determine an economic impact of BLB. In the manual-defoliation study, snap bean plants had significant yield loss when > 25% of leaf area was removed. In the field cage experiments, I was unable to establish beetle densities per plant to impact yield. Host plant selection by BLB was done in laboratory and field studies with snap bean, lima bean, and soybeans. Laboratory studies showed that BLB preferred snap bean and lima bean over soybean. Field studies did not showed no preference. A survey was conducted on the Eastern Shore of Virginia determine the epicenter of BPMV. Soybean leaves and beetles were collected and assessed for BPMV by ELISA or TBIA. Beetles at the ESAREC were BPMV-positive upon emergence from overwintering sites, but the virus load was low when tested by ELISA. This suggests acquisition of virus from a source other than infected cultivated legumes. To find the potential inoculum sources of BPMV in eastern Virginia, leguminous weeds and perennial weeds were tested for BPMV. Four weed species gave BPMV-positive tissue blots including: Oxalis stricta, Rumex acetosella, Trifolium pretense, and Trifolium repens. Insecticidal seed treatment of thiamethoxam on soybean seeds was evaluated to test the efficacy. Leaf area eaten and beetle mortality was measured. The thiamethoxam seed treatment protected soybean seedlings from beetle feeding through the V2 stage of growth. / Master of Science in Life Sciences
4

Measuring the Impact of Melaleuca quinquenervia Biochar Application on Soil Quality, Plant Growth, and Microbial Gas Flux

Velez, Thelma I. 05 November 2012 (has links)
Biochar has been heralded a mechanism for carbon sequestration and an ideal amendment for improving soil quality. Melaleuca quinquenervia is an aggressive and wide-spread invasive species in Florida. The purpose of this research was to convert M. quinquenervia biomass into biochar and measure how application at two rates (2% or 5% wt/wt) impacts soil quality, plant growth, and microbial gas flux in a greenhouse experiment using Phaseolus vulgaris L. and local soil. Plant growth was measured using height, biomass weight, specific leaf area, and root-shoot ratio. Soil quality was evaluated according to nutrient content and water holding capacity. Microbial respiration, as carbon dioxide (CO2), was measured using gas chromatography. Biochar addition at 5% significantly reduced available soil nutrients, while 2% biochar application increased almost all nutrients. Plant biomass was highest in the control group, p2 flux decreased significantly in both biochar groups, but reductions were not long term.
5

Aperfeiçoamento do processo de fermentação láctica em diferentes hortaliças e avaliação de aspectos econômicos e energéticos /

Goldoni, Cristiano Lima, 1973- January 2004 (has links)
Orientador: Ismael Antonio Bonassi / Banca: Maura Seiko T. Esperancini / Banca: Regina de Oliveira Moraes Arruda / Resumo: No presente trabalho estudou-se o comportamento das hortaliças couve-flor e feijão-vagem, submetidas ao processo de fermentação lática controlada sob temperatura de 20 C (variação de 0,5 C). O experimento constituiu-se de três ensaios de fermentação para cada uma das hortaliças: Tratamento Controle (Testemunha), Tratamento com Adição de Inóculo Comercial e Tratamento com Adição de Inóculo Comercial + Adição de Acido Lático. O monitoramento das fermentações foi realizado por meio de análises químicas, físicas, físico-químicas e microbiológicas, no decorrer e no final do processo fermentativo. Para a avaliação sensorial foram elaborados picles em vinagre de vinho branco condimentado, utilizando-se dos produtos fermentados e a matéria-prima "in natura'. A pesquisa foi complementada com o estudo do gasto de energia elétrica e do custo de elaboração dos produtos fermentados, considerando-se o processamento em laboratório; e foi determinado o consumo de energia e sua racionalização, comparando-se com o armazenamento refrigerado (processamento mínimo) das diferentes hortaliças em estudo. Os resultados obtidos através das análises químicas, físico-químicas e microbiológicas, permitiram verificar que as fermentações transcorreram normalmente, obtendo-se produtos com características desejáveis, ou seja, de alimento fermentado e produzidos com as condições tecnológicas para se apresentaram seguros, em relação aos aspectos de conservação e de saúde pública. Para ambas as hortaliças estudadas (couve-flor e feijão-vagem), os tratamentos em que houve Adição de Inóculo Comercial, resultaram em produtos com níveis mais elevados de acidez. Para couve-flor a maior acidez foi desenvolvida no tratamento com Adição de Inóculo Comercial;...(Resumo completo, clicar acesso eletrônico abaixo) / Abstract: In the present work it was studied the behavior of the vegetables cauliflower and snap-bean, submitted to the process of controlled lactic acid fermentation under temperature of 20 °C (variation of l 0,5 °C). The experiment was constituted for three trials of fermentation process for each one of the vegetables: Control Treatment (test) with Addition of Starter (Lactobacillus plantarum) and with Addition of Starter (L. plantarum) + Lactic Acid. The monitoring of the fermentations was accomplished through chemical, physical, physical-chemical and microbiological analyses, during and at the end of the fermentation process. Using the fermented products and raw vegetable, pickles were elaborated in spiced white vinegar for the purpose of sensorial evaluation. Parallelly, the research was complemented with the study of the expense of electric energy and the elaboration cost of the fermented products, being considered the processing in laboratory; and also, it was verified of the consumption of energy and its rationalization, being compared with the refrigerated storage (minimum processing) of the different vegetables in study. The obtained results through the chemical, physical-chemical and microbiological analyses, allowed to verify that the fermentations usually elapsed, being obtained products with desirable characteristics, that is to say, of fermented food and produced with the technological conditions for they came safe, in relation to the conservation aspects and of public health. For both studied vegetables (cauliflower and snap-bean), the treatments in that there were Addition of Starter, they resulted in products with a higher acidity levels. For cauliflower the greatest acidity was developed in the treatment with Addition of Starter;...(Complete abstract click electronic access below) / Mestre
6

Development and Evaluation of Integrated Approaches for Managing of Mexican Bean Beetle, Epilachna varivestis Mulsant

Nottingham, Louis B. 31 January 2017 (has links)
The Mexican bean beetle, Epilachna varivestis Mulsant, is a major pest of snap beans, Phaseolus vulgaris L. in the Central Appalachian region of the United States. To develop pertinent research objectives, background information on this pest was gathered from literature sources and personal communications with growers, extension agents and other agricultural professionals. In objective one, Mexican bean beetle preference, developmental success and plant injury were compared among three snap bean and three lima bean cultivars in field and greenhouse trials. The cultivar 'Dragon's Tongue' was the most preferred, suitable for development, and prone to injury. Growers may benefit from growing less susceptible cultivars, or by using 'Dragon's Tongue' in trap cropping or push-pull strategies. In objective two, Mexican bean beetle densities, feeding injury, and yield were compared among snap beans grown on metallized plastic (highly reflective), white plastic, black plastic, and bare soil. Metallized plastic provided the greatest level of control, and resulted in the highest yields. Managing Mexican bean beetle by growing beans on metallized plastic may be used as a stand-alone method, or in a push-pull strategy. In the final objective, the effects of snap beans grown from thiamethoxam (a neonicotinoid insecticide)-treated seeds on Mexican bean beetle were assessed in greenhouse and field experiments. Thiamethoxam-treated plants killed 40 to 50% of Mexican bean beetle adults and larvae up to 16 days after planting. In the field, thiamethoxam-treated plants mitigated Mexican bean beetle densities and damage in one out of five experiments, resulting in a yield increase. In none of the five field experiments were differences detected in predatory arthropod species between thiamethoxam and non-insecticide treated beans. In summary, the results of this project suggest that non-chemical management methods, such as cultivar selection and planting beans on reflective mulch, can provide effective control of Mexican bean beetle. Thiamethoxam-treated seed may also provide control of this pest, but only within two to three weeks after planting; otherwise, there is typically no effect on beetles, injury or yield. This doctoral research has laid a foundation for an integrated pest management approach for Mexican bean beetle. / Ph. D. / Integrated pest management (IPM) is an economical and environmentally-sensible approach to pest management that considers numerous control and decision-making strategies. This dissertation examined non-chemical strategies and the use of an insecticide seedtreatment for management of Mexican bean beetle, a major pest of green beans in the Central Appalachian region of the United States. To develop pertinent research objectives, background information on this pest was gathered from literature sources and personal communications with growers, extension agents and other agricultural professionals. In objective one, Mexican bean beetle preference, developmental success and plant injury were compared among various bean cultivars in field and greenhouse trials. The cultivar ‘Dragon’s Tongue’ was the most suitable host for Mexican bean beetle, and consequently incurred the greatest injury. Growers in high risk areas for Mexican bean beetle may benefit from growing less susceptible cultivars. In objective two, Mexican bean beetle severity and yield were compared among green beans grown on reflective metallized plastic, white plastic, black plastic, and bare soil. Metallized plastic provided the greatest level of control, and resulted in the largest yields. Our results suggest that growing beans on reflective surfaces may be an effective, chemical-free management strategy for Mexican bean beetle. In the final objective, the effects of green beans grown from thiamethoxam (a neonicotinoid insecticide)-coated seeds was examined on Mexican bean beetle severity, non-pest arthropods, and crop performance in greenhouse and field experiments. Bean plants grown from insecticide-coated seeds were highly-toxic to Mexican bean beetle for about 16 days after planting. In one out of five experiments, thiamethoxam-treated plants reduced pest levels, resulting in increased yields. More often, Mexican bean beetles arrived after the insecticide had disappeared from plants and there was no effect. There were no detectable effects from the thiamethoxam treatment on non-pest arthropods in any experiment. Overall, seed-treatments may provide occasional control of Mexican bean beetle, but non-chemical methods may be as effective and more practical. This doctoral research project has provided a foundation for an integrated pest management approach for Mexican bean beetle.

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