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1
Dennis, Jeremy Ian. "Chocolate spot of faba beans in South Australia". Title page, contents and summary only, 1991. http://web4.library.adelaide.edu.au/theses/09A/09ad411pdf.pdf.
Testo completoAbstract (sommario):
Bibliography: leaves 81-100. Entry of inoculum into a crop and disease development in the crop cannot be prevented because spores are airborne and there is a lack of highly resistant varieties. This makes complete control of chocolate spot unlikely. It should however, be possible to improve current levels of disease control through the integration of the factors identified in the study.
2
Yakop, Uyek Malik. "Resistance of faba beans to Ascochyta blight". Title page, contents and summary only, 1998. http://web4.library.adelaide.edu.au/theses/09APSM/09apsmy15.pdf.
Testo completoAbstract (sommario):
Bibliography: leaves 111-120. This study investigated various aspects of genetic resistance in fava beans to Ascochta blight (A. fabae) with the objective to facilitate an efficient breeding strategy for long-term control. Pathogenic variability of A. fabae was found to be high, as was genetic variation between resistant fava bean accessions. A number of alternative resistance genes to that of Ascot cultivar were identified.
3
Lawsawadsiri, Somporn. "Variation in resistance to Ascochyta blight in faba beans". Title page, contents and summary only, 1994. http://web4.library.adelaide.edu.au/theses/09PH/09phl425.pdf.
Testo completo
4
Noronha, Christine M. (Christine Mary). "Effects of density and host plant type on fecundity and survival of Delia radicum (Bouché), D. Antiqua (Meigen) and D. Platura (Meigen) (Diptera: Anthomyiidae)". Thesis, McGill University, 1992. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=41017.
Testo completoAbstract (sommario):
The effects of intraspecific and interspecific competition, host plant, and prior host plant experience on fecundity, rate of oviposition and mortality of adults and larval survival of Delia radicum Bouche (Cabbage Maggot (CM)), D. antiqua Meigen (Onion Maggot (OM)), and D. platura Meigen (Seed Corn Maggot (SCM)), were studied on cabbage, onion and bean plants.An optimum density for maximum fecundity per female was observed when the four experimental densities were compared. This optimum density was higher on host than on non-host plants. CM females were host specific and did not oviposit on non-host plants. Rates of oviposition and mortality over a 30-day period were calculated for each density. The rate of oviposition was slower at higher densities on host plants for CM, OM and SCM. The rate of mortality increased at the highest density for CM (cabbage), OM (bean) and SCM (cabbage), but remained unaffected for OM on onion and cabbage and for SCM on onion and bean, when densities were compared. For OM, a delay in the rate of oviposition and mortality on cabbage (non-host plant) when compared with onion (host plant), suggests that cabbage was not as readily accepted as an oviposition site. Interspecific competition experiments at six density ratio's of SCM:OM indicated increased fecundity, or an increase in the rate of oviposition for OM, at the lower densities when single and mixed species were compared. For SCM no effects on fecundity were recorded, but the rate of oviposition was slower and rate of mortality faster at the lowest density in the presence of OM. Similar studies with SCM and CM showed no such effects of competition.
Host plant exposure of SCM females during the pre-oviposition period resulted in a delay in initial acceptance of subsequent host plants as oviposition sites. This happened only when females were exposed to a secondary host during the pre-oviposition period. Once oviposition began, host discrimination ceased and a switch in oviposition sites to the preferred host did not alter the rate of oviposition. In CM, the rate of larval development increased at density 6 (optimum density). Above this density a decrease in the rate of development and a significant reduction in pupal weight was observed. Time required for fly emergence was not affected by increasing larval densities.
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Jimenez, Garcia Emilio. "ETIOLOGY, PATHOLOGY AND CHARACTERIZATION OF VIRUSES FROM BEANS GROWING IN THE SONORA DESERT OF MEXICO (COWPEA, CHLOROTIC MOTTLE)". Diss., The University of Arizona, 1985. http://hdl.handle.net/10150/187907.
Testo completoAbstract (sommario):
Survey of crops of common bean (Phaseolus vulgaris L.) in Sonora, Mexico revealed the presence of two isometric viruses and one flexuous rod virus on the basis of host reaction, particle morphology, serology and physico-chemical properties. The isometric viruses were identified as Bean Southern Mosaic Virus (BSMV) and Cowpea Chlorotic Mottle Virus (CCMV); the flexuous rod virus was identified as Bean Common Mosaic Virus (BCMV). Using bean cultivar differentials, two strains of the potyvirus BCMV were identified, NY-15 and a previously undescribed strain designated YV-1. Host range, serological tests, and RNA electrophoresis indicated that the Sonoran BSMV cultures are similar to BSMV-strain A. Serology and RNA-electrophoresis indicated that the Sonoran CCMV isolates are identical to CCMV-strain A. BSMV and CCMV were always isolated as a mixture from seed lots and from field collected bean tissue. BCMV occurred alone or in mixed infections with BSMV and CCMV. BCMV was seed transmitted with an average efficiency of 58 percent. The BSMV-CCMV mixture was transmitted with an efficiency of 6 percent. BSMV and CCMV were seed transmitted together, but separate transmission of BSMV or CCMV was not detected. Commercial seed lots from two major bean growing regions of Sonora (Hermosillo Coast, Sonora River) were contaminated with the BSMV-CCMV mixture but not with BCMV. The average contamination level was 13 percent. Two common weeds present in Sonoran agricultural areas were found to be potential alternate hosts of CCMV. Both Sisymbrium irio L. and Melilotus indica L. were infected systemically, although the infection in M. indica was latent. Potential losses due to Sonoran bean viruses were measured in greenhouse experiments with the cultivar Pinto 111. BCMV strains caused a 29.4 to 60.1% reduction, whereas BSMV-CCMV mixtures induced a 22.5 to 74.6% yield reduction. A synergism occurred between the BSMV-CCMV mixture and BCMV resulting in more severe symptoms and a yield reduction of 92.7%. Synergistic effects were also observed between BSMV and CCMV. Actual yield reduction resulted from impaired flower production and, consequently, reduced pod production. Significant effects on plant tissue production, flower fertilization and seed quality were not observed. Cowpea chlorotic mottle virus infected mung bean (Vigna radiata (L.) Wilczek) a previously unreported host. Infection of mung bean by BSMV was only possible when CCMV was present in the inoculum. Both BSMV and CCMV could be isolated from symptomatic plants infected with the BSMV-CCMV mixture, however, symptoms on mung bean were unchanged from infection by CCMV alone.
6
Ferguson, Kaye. "The biology, ecology and management of the Quandong moth, Paraepermenia santaliella (Lepidoptera: Epermeniidae)". Title page, contents and summary only, 2001. http://web4.library.adelaide.edu.au/theses/09PH/09phf3523.pdf.
Testo completoAbstract (sommario):
Includes bibliographical references (leaves 217-230). Details the biology and life history of the Quandong moth and investigates management strategies that would enable growers to manage the pest in an economically and environmentally sustainable program.
7
Cieslik, Lucas Fernando. "Interferência de fatores morfoambientais e horários de aplicação de fluazifop-p-butyl e fomesafen no controle de infestantes, seletividade e lucratividade da cultura do feijoeiro (Phaseolus vulgaris L.)". Universidade Tecnológica Federal do Paraná, 2012. http://repositorio.utfpr.edu.br/jspui/handle/1/263.
Testo completoAbstract (sommario):
Fundação Araucária, CNPQPlantas daninhas competem com as cultivadas e dentre as influências negativas desse convívio está a redução da produtividade das culturas. O controle químico é a principal forma de gestão das infestantes na cultura do feijão (Phaseolus vulgaris L.). Sua eficácia depende de uma série de fatores, entre eles: condições ambientais (em função dos horários de aplicação) no momento da aspersão do herbicida e doses utilizadas. Um programa de pesquisa foi desenvolvido no curso de Agronomia da UTFPR, Pato Branco, PR, durante a safra 2010/11 com os objetivos gerais de analisar o impacto de horários de aplicação (e por consequência das variáveis ambientais) e de doses de fluazifop-p-butyl e de fomesafen sobre: o desempenho desses herbicidas no controle de plantas daninhas mono e dicotiledôneas, respectivamente; a seletividade do feijoeiro ao fomesafen e; a lucratividade da lavoura de feijão. As variáveis ambientais, de acordo com o horário do dia ou a época do ano em que os produtos foram aplicados, influenciaram no controle das infestantes. Fluazifop-p-butyl teve atividade favorecida quando aspergido às 06:00h, com umidade relativa do ar e ângulo foliar das gramíneas influenciando de maneira mais significativa no resultado. Para esse mesmo herbicida, aplicação noturna foi eficaz em mitigar os efeitos negativos da aplicação vespertina. O desempenho de fomesafen no controle das plantas daninhas dicotiledôneas foi máximo quando o produto foi aspergido às 11:00h e às 16:00h. Nesse caso, a irradiância e a temperatura do ar foram os principais determinantes da eficácia do herbicida. As doses de fluazifop-p-butyl + fomesafen que propiciaram maior controle da infestação resultaram em aumento da produtividade do feijoeiro e da rentabilidade da produção. Em alguns casos, a maximização da renda líquida foi obtida com dose menor do que a recomendada no rótulo do produto e aquela necessária para a obtenção da máxima eficácia do produto. Fomesafen provocou toxicidade nas plantas de feijão, as quais recuperaram-se das injúrias com o decorrer do tempo. O grau de fitointoxicação foi mais acentuado com doses elevadas do produto e quando esse foi aspergido às 11:00h e às 16:00h. Nesses horários, a temperatura do ar e a irradiância estavam mais acentuadas. Pode-se sintetizar que a eficácia no controle das plantas infestantes e a toxicidade dos herbicidas ao feijoeiro foram dependentes dos herbicidas utilizados, das condições ambientais em função do horário do dia em que os herbicidas foram aplicados e das doses utilizadas. A escolha correta do horário e da dose de aplicação favorece a eficiência do controle das plantas daninhas, minimiza os prejuízos à cultura em função da competição e eleva a lucratividade da lavoura.
The weeds compete with the cultivated crops and among the negative effects of this interaction is the reduction of the crop yields. The chemical method is the main weed control technic in the common bean crop (Phaseolus vulgaris L.). The efficacy of the herbicides depends on a number of factors, including: environmental conditions (in function of the time of application) at the moment of spraying of the herbicide and doses used. A research program was developed on the Agronomy course of UTFPR, Pato Branco, PR, during the 2010-11 with the main objectives to evaluate the impact of the application time (and therefore environmental variables) and doses of fluazifop-p-butyl and fomesafen on the: performance of these herbicides in the control of mono and dicotyledonous weeds, respectively; selectivity of bean crop to fomesafen; and the lucrativity of the common bean crop. The environmental variables, according to the time of day or season of year in which herbicides were applied, influence the control of weeds. Fluazifop-p-butyl activity has been favored when sprayed at 06:00h. The relative humidity and grass leaf angle were the factors most important affecting this herbicide performance. For this same compound, night application has been effective to mitigate the negative effects of the afternoon application. The performance of fomesafen to control broadleaf weeds has been maximum when the product was sprayed at 11:00h and 16:00h. In this case, the irradiance and the air temperature have been the main factors to affect the herbicide efficacy. The doses of fluazifop-p-butyl + fomesafen which allowed best weed control have increased grain yield and profitability of the common bean crop production. In some cases, the maximum net return has been obtained with a dose lower than that needed for maximum herbicide efficacy. Fomesafen has injured the common bean plants, but they have recovered with time. The degree of phytointoxication has increased at high fomesafen doses and when it has been sprayed at 11:00h and 16:00h. During these times, the air temperature and irradiance were the highest. It can be summarized that the efficacy on weed control and on the common bean injury was dependent on the herbicide used, on the environmental conditions during the time of the herbicide spray, and on the rates applied. The selection of the correct time of the day and rate of application can optimize the weed control, can reduce the crop yield losses due to competition, and can optimize the crop profitability.
8
Machado, Adriano Bressiani. "Impacto agronômico e dano econômico da interferência entre leiteiro (Euphorbia heterophylla) e feijoeiro (Phaseolus vulgaris) em intervalos distintos de semeadura". Universidade Tecnológica Federal do Paraná, 2012. http://repositorio.utfpr.edu.br/jspui/handle/1/265.
Testo completoAbstract (sommario):
A cultura do feijoeiro apresenta grande importância econômica para o Brasil e especificamente para a região do Sudoeste do Paraná, onde é cultivado principalmente em pequenas e médias propriedades. Constitui-se em um dos alimentos mais ricos consumido pelo povo brasileiro, principalmente para as populações mais pobres. É imprescindível o estudo cientifico dos sistemas de produção e o avanço tecnológico para aumentar sua produtividade e rentabilidade. Entre os gargalos limitantes à cultura, está a necessidade de estudar melhor os níveis populacionais de plantas daninhas que justificam o seu controle atendendo a critérios econômicos, o que resultaria em maior segurança para tomada de decisões de controle e, conseqüentemente, maior economia aos produtores rurais. Nesse contexto, realizou-se um experimento na área experimental da Universidade Tecnológica Federal do Paraná, Campus Pato Branco, com objetivo de verificar o nível de dano econômico e competitivo de Euphorbia heterophylla sob diferentes densidades e épocas de semeadura desta infestante em relação à cultura do feijoeiro. O experimento foi conduzido a campo em delineamento de blocos ao acaso, em parcelas subdivididas, com quatro repetições. Nas parcelas principais foram locadas oito densidades esperadas de E. heterophylla (0, 6, 10, 17, 29, 49, 83 e 142 pl m-2) e nas subparcelas duas épocas de semeadura de E. heterophylla (12 dias antes da semeadura do feijão e simultaneamente a cultura). Foram realizadas avaliações das características agronômicas das plantas de feijão e morfológicas de E. heterophylla e feijão durante o período de desenvolvimento e no momento da colheita da cultura. No cálculo das perdas de rendimento foi empregado o modelo da hipérbole retangular e pelo método de segmentação linear, sendo extraídos os parâmetros “i” (perda percentual por cada planta de E. heterophylla), que foram empregados no cálculo do nível de dano econômico. A antecipação da semeadura de E. heterophylla, bem como o incremento na densidade acarretaram redução da produtividade da cultura do feijão, devido principalmente à redução do número de legumes por planta. A interferência de plantas de E. heterophylla com a cultura do feijão determinou redução da estatura de plantas, índice de área foliar, massa seca, número de trifólios, número de ramificações produtivas, mas houve aumento da altura de inserção de legumes da cultura. A semeadura antecipada de E. heterophylla proporciona maior desenvolvimento desta espécie em relação à época de semeadura simultânea com a cultura do feijão, refletindo-se no aumento da área foliar, da massa seca e da cobertura do solo pela espécie daninha. A perda percentual por planta daninha pode ser estimada adequadamente através dos diferentes modelos utilizados. Tanto o modelo hiperbólico quanto o linear indicam maior perda percentual quando a semeadura de E. heterophylla ocorre antecipadamente à cultura do feijão comum. O modelo hiperbólico superestima os valores de nível crítico de dano em relação ao modelo linear. O aumento na perda de rendimento por unidade de planta daninha, rendimento da cultura, eficiência do herbicida e no valor do produto colhido ocasionam diminuição dos valores dos níveis de dano econômico. No entanto, o aumento do custo de controle de plantas de E. heterophylla aumenta os valores do nível de dano econômico.Bean crop has great economic importance to Brazil and specifically for the South West of Parana, where it is grown mainly in small and medium farms. It constitutes one of the richest foods consumed by the Brazilian people, especially for the poorest populations. In this context, the scientific study of production systems and technological advances are essential to increase productivity and profitability. Among the factors that limit crop development, is the need to better understand the weed population levels that justify its control attending economic aspects, which would result in better control decision-making and, consequently, lower costs to farmers. In this context, an experiment was carried out at the experimental area of the Federal Technologic University of Paraná, Campus Pato Branco, in order to verify the economic injury level and competitive potential of the Euphorbia heterophylla under different sowing dates and densities of this weed in relation to the bean crop. The experiment was laid out as a randomized blocks arranged in a split-plots design with four replications. At the main plots were located eight expected densities of E. heterophylla (0, 6, 10, 17, 29, 49, 83 and 142 pl m-2) and at the subplots two sowing dates of E. heterophylla (12 days before bean sowing and at the crop sowing day). Evaluations were made on the agronomic characteristics of the bean plants during its development and at the harvest period. Moreover, morphological characteristics of the E. heterophylla and the beans were also evaluated at the same periods. To determine the crop yield losses was used the hyperbolic model and the linear segmentation method, and extracted the parameters "i" (percentage loss per plant of E. heterophylla), which were used in calculating the economic injury level. E. heterophylla sowed before the crop as well as its density increase led to reduced productivity of the bean, mainly due to reduction in the number of pods per plant. Moreover, the interference of the E. heterophylla on the bean crop resulted in lower plants, reduced leaf area index, lower dry weight, less number of leaves, less number of productive branches, however resulted in shorter height of the pods insertion on the crop. Early sowing of E. heterophylla results in better development of the weed specie in relation to the sowing data were both, weed and crop are sowed at the same day, resulting on higher leaf area, higher dry matter production and soil cover by the weed species. Percentage of yield losses due to the weed plant presence could be adequately estimated through the different models used. Both the linear and the hyperbolic model indicate a higher percentage loss when the sowing of E. heterophylla occurs before than the common bean crop. The hyperbolic model overestimates the values of the critical level of damage in relation to the linear model. Increases on the yield losses per unit weed, lower crop yield, lower herbicide efficiency and lower value of the harvested product resulted in smaller values of the economic injury level. Although, as the E. heterophylla control cost increase, the economic injury level also increases.
9
White, John Gordon. "Control of rodent damage in Australian macadamia orchard systems". Thesis, Queensland University of Technology, 1999.
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10
Bressan, Dayanne Fabrício. "Uso dos eliciadores acibenzolar-s-metílico e harpina na indução de resistência em plantas de feijoeiro comum ao crestamento bacteriano". Universidade Tecnológica Federal do Paraná, 2011. http://repositorio.utfpr.edu.br/jspui/handle/1/232.
Testo completoAbstract (sommario):
CAPESO crestamento bacteriano comum, causado por Xanthomonas axonopodis pv. phaseoli, é uma das principais doenças da cultura do feijoeiro. Em busca por alternativas no controle de doenças em plantas, o uso de eliciadores/indutores de resistência tem sido explorado. Desta forma, o objetivo deste trabalho foi verificar a eficiência dos eliciadores harpina e acibenzolar-S-metílico na indução de mecanismos de defesa em plantas de feijoeiro (Phaseolus vulgaris L.) ao crestamento bacteriano comum, causado por X. axonopodis pv. phaseoli, avaliandose possíveis alterações no processo de trocas gasosas e ativação das principais enzimas envolvidas na defesa vegetal - peroxidase, superóxido dismutase, além de proteínas e fenóis. Foram utilizadas sementes dos cultivares IAPAR 31 e IPR Colibri. Depois de emergidas as primeiras folhas trifoliadas na fase vegetativa (V3) as plantas, foram tratadas com os eliciadores acibenzolar-S-metílico, harpina e água destilada (controle). Sete dias após a primeira aplicação dos eliciadores, foi inoculado o patógeno nas folhas do feijoeiro. A avaliação da severidade foi realizada a cada 10 dias sendo a primeira avaliação realizada 15 dias após a inoculação do patógeno. As leituras de fotossíntese foram realizadas 40 dias após a inoculação quando os sintomas e danos da doença demonstravam-se estabelecidos. Para a realização das análises bioquímicas, amostras de tecidos foliares de cada tratamento foram coletadas 24 horas antes, 24, 48 e 72 horas após a aplicação dos eliciadores. Também, foram determinados o rendimento e seus componentes em ambas as cultivares.A aplicação de ASM e harpina proporcionou redução na severidade da doença do crestamento bacteriano comum nas plantas de feijoeiro da cultivar IPR-Colibri e a mesma tendência foi observada para a cultivar IAPAR 31 tratada com ASM. As plantas da cultivar IAPAR 31 tratadas com o eliciador ASM, apresentaram maiores taxas de assimilação de CO2 quando comparadas ao controle e a mesma tendência foi observada para a cultivar IPR-Colibri. A aplicação do ASM promoveu o aumento da atividade da enzima antioxidativa peroxidase e a indução da síntese de compostos fenólicos e especialmente na cultivar suscetível IPRColibri. Para o rendimento de grãos e seus componentes, não foram observadas diferenças significativas entre o controle e os eliciadores ASM e harpina. Os eliciadores ASM e harpina induziram os mecanismos de resistência em feijoeiro contra X. axonopodis pv. phaseoli, indicando a potencialidade do uso dos eliciadores na cultura do feijoeiro.
The common bacterial blight, caused by Xanthomonas axonopodis pv. phaseoli is one of the major diseases of the bean crops. In search for alternatives to control the plant diseases, the use of the elicitors / inductors of resistance has been explored. Thus, the objective of this work was to verify the effectiveness of the elicitors harpina and acibenzolar-S-methyl in the induction of the defense mechanisms in bean plants (Phaseolus vulgaris L.) against common bacterial blight caused by X. axonopodis pv. phaseoli, evaluating the possible changes in the process of gas exchange and the activation of the key enzymes involved in the plant defense - peroxidase, superoxide dismutase, besides proteins and phenols. It was used seeds from IAPAR 31 and IPR Colibri cultivars. After emerged the first trifoliate leaves in the vegetative stage (V3) the plants were treated with the elicitors Acibenzolar-S-methyl and harpina, and distilled water (control). Seven days after the first application of the elicitors, the pathogen was inoculated on the leaves of bean plants. The severity assessment was performed every 10 days and the first evaluation 15 days after the pathogen inoculation. The measurement photosynthesis were performed 40 days after the inoculation when the symptoms and the damages of the disease showed themselves established. To carry out the biochemical analysis, samples of leaf tissue from each treatment were collected 24 hours before, 24, 48 and 72 hours after the application of the elicitors. Also, it was determined the yield and its components in both cultivars. The application of ASM and harpina provided the reduction in the severity of the common bacterial blight disease of the bean plants of IPR-Colibri cultivars and the same trend was observed for the IAPAR 31 cultivars treated with the elicitor ASM. Plants by IAPAR 31 treated with the elicitor ASM showed higher rates of assimilation of CO2 when compared to the control and the same trend was observed for cultivar IPR-Colibri. The application of ASM promoted the increase of the antioxidative enzyme peroxidase activity, and the induction of the phenolic compounds synthesis and, especially in the susceptible cultivar IPR-Colibri. For grain yield and its components, significant differences were not observed between the control and the elicitors ASM and harpina. The elicitors ASM and harpina induced the resistance mechanisms in bean plant against X. axonopodis pv. phaseoli, indicating the potentiality of the elicitor utilization in bean crops.
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Lagos, Frank Silvano. "Uso do leite de vaca no controle do oídio em feijão-de-vagem". Universidade Tecnológica Federal do Paraná, 2009. http://repositorio.utfpr.edu.br/jspui/handle/1/239.
Testo completoAbstract (sommario):
A crescente procura por alimentos mais saudáveis demanda um aumento na produção isenta de agrotóxicos. O feijão-de-vagem é uma das principais olerícolas cultivadas no Brasil. Dentre as principais doenças que afetam essa cultura está o oídio, podendo ocasionar perdas de produção em até 69%, sendo de ocorrência comum em cultivos protegidos especialmente em períodos tardios. O uso do leite tem demonstrado boas perspectivas no controle desta doença em diversas culturas. Foram desenvolvidos na Universidade Tecnológica Federal do Paraná – Campus de Pato Branco – PR, nos anos de 2007 e 2008, trabalhos com o objetivo de avaliar o efeito do leite de vaca in natura e seus possíveis mecanismos de ação sobre o controle de oídio em feijão-de-vagem sob ambiente protegido. Conduziu-se experimento com aplicação de leite de vaca in natura nas concentrações de 0%, 5%, 10%, 15% e 20% em freqüência semanal e quinzenal, com e sem espalhante adesivo. Foi avaliada a severidade da doença e a produtividade. O delineamento foi em blocos ao acaso, com 4 repetições. Em outro experimento avaliou-se o efeito dos componentes químicos do leite, com aplicações foliares de Nitrato de Potássio (0,79 g L-1), Cloreto de Amônio (0,82 g L-1), Nitrato de Cálcio (0,96 g L-1), Fosfato de Amônio Monobásico (0,51 g L-1), Carbonato de Sódio (0,23 g L-1), mistura destes componentes, leite (200 ml L-1) e água. O delineamento foi inteiramente casualizado com 3 repetições. No terceiro experimento avaliou-se a atividade metabólica em tecidos foliares de feijão-de-vagem tratado com aplicações semanais de leite de vaca in natura nas concentrações do primeiro experimento. O cultivo foi em vasos, em casa de vegetação com ambiente controlado. O delineamento foi inteiramente casualizado com 4 repetições. Para realização das análises bioquímicas (proteínas, açúcares totais e redutores, peroxidases e FAL) foram coletados discos foliares de 0,2 g de cada unidade experimental, 24, 48 e 72 horas após a aplicação do leite de vaca in natura. O leite aplicado em freqüência semanal promoveu controle do oídio de 37,94 a 79,96%. Em freqüência quinzenal o controle variou de 22,32 a 28,59%, sendo mais efetivo no início da infestação. Sua aplicação não requer uso de espalhante adesivo. As concentrações mais viáveis foram entre 10 e 15%. Aplicação dos diferentes componentes químicos de forma combinada controlou a doença de forma semelhante à aplicação do leite de vaca in natura. Aplicações de concentrações crescentes de leite de vaca in natura interferiu nos parâmetros bioquímicos foliares de proteínas, açúcares totais e redutores, atividade de peroxidase e FAL, demonstrando ser um elicitor capaz de induzir a uma resposta de resistência, alterando a atividade de enzimas relacionadas com a defesa do feijão-de-vagem.The rising search for healthier food demands a rising in the production without fertilizers. The bean pod is one of the main plants from the vegetable gardens grown in Brazil. Among the main diseases which affect this culture is the powdery mildew which can cause losses in the production up to 69%, being a common occurrence in protected cultures especially in late periods. The usage of milk has shown good perspectives in this disease control in different cultures. Works with the aim of evaluate the effect of in natura milk and its possible mechanisms of action in the powdery mildew control in bean pods under a protected environment were developed during 2007 and 2008. In the Federal Technological University of Paraná – campus in Pato Branco- PR. The experience was conducted with the application of in natura milk in the concentrations of 0%, 5%, 10%, 15% and 20% every week or every fifteen days with or without the adhesive spreader. The severity of this disease was evaluated as well as the productivity. The design was in blocks at random, with four repetitions. In other experiment it was evaluated the milk chemical components effect with application leaf of Potassium Nitrate (0.79 g L-1), Ammonium Chloride (0.82 g L-1), Calcium Nitrate (0.96 g L-1), Ammonium Phosphate Monobasic (0.51 g L-1), Sodium Carbonate (0.23 g L-1), mixture of these components, milk (200 ml L-1) and water. The design was entirely developed with three repetitions. In the third experiment the metabolic activity was evaluated in the follicular tissue in bean pods treated with weekly applications of cow milk in natura in the concentrations of the first experiment. The cultivation was in vases in a vegetation house with controlled environment. The design was entirely developed with four repetitions. In order to make the biochemical analysis (proteins, total sugar and reductors, peroxidasis e PAL) Follicular disks of 0.2g were collected from each experimental unity, 24, 48 e 72 hours after the application of cow milk in natura. The milk applied weekly promoted the powdery mildew control of 37.94 to 79.96%. Being used every fifteen days the control varied from 22.32 to 28.59%, being more effective in the beginning of the infestation. Its application does not require the usage of adhesive spreader. The most variable concentrations were between 10 e 15%. The application of different chemical components in a combined form controlled the disease in a similar way to the application of cow Milk in natura. The applications of rising concentrations of cow milk in natura interfered in the follicular biochemical patterns of proteins, total sugar and reductors, activity of peroxidasis and PAL demonstrating to be an elicitor which is able to induct to an answer of resistance, alternating the enzymatic activity related to the bean pod defense.
12
Evans, Katherine J. "Characterization of Uncinula necator, the grapevine powdery mildew fungus". Title page, contents and abstract only, 1996. http://web4.library.adelaide.edu.au/theses/09PH/09phe924.pdf.
Testo completoAbstract (sommario):
Bibliography: leaves 148-166. This study identifies genetic variation in Australian Uncinula necator populations. Techniques were developed for molecular and phenotypic markers for U. necator. Mating types of Australian clonal lines were identified and viable cleistothecia and infective ascospores were produced in vitro. The study establishes the foundation for investigating the population biology of U. necator, by identifying two distinct genetic groups, A and B, and micro-geographical variation among 35 clonal lines from various Australian viticultural regions.
13
Khan, Muhammad Shahid Akhtar. "Epidemiology of ascochyta blight of chickpea in Australia". Title page, contents and summary only, 1999. http://web4.library.adelaide.edu.au/theses/09PH/09phk4455.pdf.
Testo completoAbstract (sommario):
Bibliography: leaves 182-217. This study was conducted to determine the etiology of a blight disease of chickpea in south-eastern Australia and the factors affecting disease development. The disease had previously been identified as phoma blight. Pathogenicity testing revealed two isolates subsequently identified as Asochyta rabiei, the first conclusive identification in the southern hemisphere. Greenhouse screening of chickpea varieties identified types resistant to ascochyta blight. The effects of plant age and environmental conditions on disease development were investigated under controlled conditions in growth rooms. Seedlings were more susceptible than older plants. The optimum conditions for ascochyta blight were 20° C and a 48-96 h period of leaf wetness. Through field trials it was found that disease intensity increased over time, especially in cv. Desavic. The means of penetration of the chickpea host was established in histological studies. This study provided advance warning of this disease for the expanding chickpea industry, and has allowed the implementation of appropriate disease management strategies. It is recommended that cv. Desavic should not be grown where ascochyta blight is likely to be a problem.
14
Nicol, Julie. "The distribution, pathogenicity and population dynamics of Pratylenchus thornei on wheat in South Australia". Title page, contents and summary only, 1996. http://web4.library.adelaide.edu.au/theses/09PH/09phn634.pdf.
Testo completoAbstract (sommario):
Bibliography: leaves 224-236. The study aimed to determine the distribution of both P. thornei and P. neglectus in South Australia. Also to study the field and laboratory population dynamics of P. thornei in relation to wheat yields, to determine its host range on a variety of cereal and non-leguminous hosts and to identify possible sources of nematode resistant wheat cultivars/varieties. Preliminary experiments studied the involvement of root rotting fungi with the nematode in wheat disease.
15
Persley, Denis Michael. "Identification, epidemiology and control of Papaya ringspot virus, recently recorded in papaya (Caricus papaya) in Australia". Thesis, Queensland University of Technology, 1997. https://eprints.qut.edu.au/36937/1/36937_Persley_1997.pdf.
Testo completoAbstract (sommario):
Papaya (Carica papaya), originating in South America, is widely-grown throughout the tropical and sub-tropical regions of the world. The popularity and versatility of the fruit and commercial uses of papain obtained from papaya latex have made the crop an important component of cropping systems in many developing countries where 98% of production is centred. Papaya ringspot virus (PRSV) is the major limiting factor to papaya production in many countries, particularly those in SouthEast Asia and South America. Papaya ringspot disease was first detected in Queensland in 1991, with several commercial plantations being severely affected. Effective control of a disease requires an efficient detection system, a knowledge of disease epidemiology under local conditions and an assessment of potential control strategies. These objectives were addressed in this thesis.
A Queensland isolate of PRSV-P (338 Wamuran) was purified and polyclonal antiserum produced. The antiserum was used in double-antibody sandwich and plated trapped antigen ELISA formats to detect PRSV in papaya and cucurbit samples. Although papaya sap was shown to inhibit ELISA reactions, antisera to PRSV-338 or PRSV-HA (Hawaii) provided a satisfactory screening assay for all samples tested from papaya and cucurbits. Isolates of PRSV-P and -W from the Philippines, Thailand, Hawaii and Vietnam were serologically indistinguishable in PTA-ELISA using PRSV-338 and PRSV-HA antiserum.
The ability of PRSV to spread rapidly within a plantation in the absence of roguing was demonstrated at Bridgeman Downs where virus incidence increased from zero to 95% in six months in plants established adjacent to infected papayas. Despite the capacity of PRSV-P to rapidly spread within a plantation, the distribution of PRSV-P in Queensland has not substantially altered since its detection in papaya in February 1991 in south-east Queensland. Three significant outbreaks have occurred in commercial plantations since 1991 but were contained by roguing infected plants. The slow spread of PRSV-P in Queensland, in contrast to most other countries where the virus occurs, may be due to the physical separation of many plantations and the natural barriers of forest, grassland and non-susceptible crops which have restricted virus spread. Roguing has proved effective in containing local outbreaks of PRSV.
The experimental host range of PRSV in Queensland was confined to Cucurbitaceae and Caricaceae. Commercially available cultivars of Citrullus lanatus, Cucumis melo, C. sativus, Cucurbita pepo, C. maxima and C. moschata were all highly susceptible to both PRSV-P and -W following manual inoculation. An isolate of each PRSV-W (DBI) and PRSV-P (338) also infected a proportion of inoculated plants of Benincasa hispida, Citrullus colcynthis, Lagenaria siceraria, Luffa cylindrica and Momordica charantia. When species and accessions of Cucumis and Cucurbita were screened by manual inoculation, Cucumis africanus, C. callosus C. ficifolius, C. leptodermis, C, membranifolius and C. zeyheri were determined as new experimental hosts of PRSV-P and -W. Citrullus colocynthis, Cucumis dipsaceus, C. meeusei and Cucurbita pepo var. fraterna are previously unreported hosts of Australian PRSV-P and -W. Several accessions of Cucumis metuliferus and Cucurbita foetidisima were resistant to PRSV-P (338) and -W (DBI).
Isolates of PRSV-P, but not PRSV-W, infected Carica papaya, C. parviflora, C. pentagonia, (babaco) and C. goudotiana but not Carica cauliflora, C. pubescens, C. stipulata, C. quercifolia or Jacaratia spinosa.
When 114 plants of the interspecific hybrid Carica papaya x C. cauliflora were inoculated with PRSV-P, 92 of the hybrid plants died, presumably due to genetic incompatibility, before virus assays could be completed. The remaining 22 plants did not develop symptoms and virus was not detected by ELISA or back- inoculation to Cucurbita pepo test plants.
The natural host range of PRSV-P in Queensland was confined to Carica species and, importantly, several cucurbit species. Mosaic and mottle symptoms developed in commercial cultivars of pumpkin (Cucurbita maxima), squash (Cucurbita pepo) and zucchini (Cucurbita pepp var melopepo) in two field experiments planted adjacent to infected papaya plants. PRSV-P was confirmed in symptomatic cucurbits by ELISA and inoculation to young plants of Carica papaya. This appears to be the first experimental demonstration that cucurbits are natural hosts of PRSV-P and is discussed in relation to the possible origin of PRSV-P in Queensland. In a separate trial at a location where PRSV did not naturally occur, it was shown that PRSV-P could be transmitted by aphids from PRSV-P inoculated zucchini to papaya plants. In this trial, 21 of 26 papaya plants had developed typical PRSV symptoms nine weeks after transplanting.
PRSV-P was not found in samples obtained from 12 common weed species growing in a plantation where PRSV-P - infected papaya plants had been present for several years.
Seed transmission of PRSV-P was not detected in plants grown from seed collected from infected plants at Dayboro, Qld, the Philippines and Malaysia.
Four cultivars (Red Luck, Known You No. 1, Tainung 5, Cariflora) with reputed tolerance to PRSV-P were compared with the commercial cultivar Richter Gold in a field trial where they were exposed to natural infection by PRSV-P. The period from planting to 50% of plants with symptoms was eight weeks for Richter Gold and from 15 to 22 weeks for the four tolerant cultivars. Cariflora developed the mildest leaf symptoms but had very poor fruit set. Plants of Red Luck, Known You No. I and Tainung 5 developed severe leaf symptoms. Fruit set was greatest in Red Luck and Known You No. 1 after one year's growth. Although none of the cultivars had outstanding tolerance to PRSV-P in Queensland, it was concluded that further selection could be undertaken in Red Luck and Known You No. 1 to increase tolerance levels and adaptability.
Despite the very limited molecular variation detected between PRSV isolates from Queensland, considerable biological variation was detected between some PRSV-P isolates. This was particularly marked when the tolerant cultivars and Richter Gold were inoculated with either one of two isolates of PRSV-P (338 or 445) in a glasshouse. Leaf symptoms and the degree of stunting were very severe on plants inoculated with isolate 445. Comparative virus concentrations were inversely correlated with symptom severity. Absorbance values (A41onm) were significantlyhigher (P < 0.01) for both isolates in all four tolerant cultivars compared with Richter Gold and significantly less (P < 0.01) for isolate 445 in Know You No. 1, Tainung 5 and Richter Gold, all of which developed severe leaf symptoms and stunting with this isolate. The possible origins of this variation and the implications to control programs are discussed.
16
Balali-Dehkordi, Gholam Reza. "Genetic variation of Rhizoctonia solani AG-3 in South Australia". Title page, contents and abstract only, 1996. http://web4.library.adelaide.edu.au/theses/09PH/09phb171.pdf.
Testo completoAbstract (sommario):
Three pages of addenda pasted inside back cover. Bibliography: leaves 166-189. Rhizoctonia solani is a complex species comprising morphologically basidiomycetous imperfect fungi. This study aimed to determine genetic diversity within R. solani AG-3 causing rhizoctonia disease of potato in South Australia. For this purpose, pectic zymogram, PCR, DNA fingerprinting and RFLP techniques were used in conjunction with traditional plant pathology procedures.
17
Frost, William E. "The ecology of cereal rust mite Abacarus hystrix (Nalepa) in irrigated perennial dairy pastures in South Australia /". Title page, contents and summary only, 1995. http://web4.library.adelaide.edu.au/theses/09PH/09phf9398.pdf.
Testo completo
18
Akiew, E. B. "Potato diseases in South Australia : studies in leafroll, early blight and bacterial wilt /". Title page, contents and summary only, 1985. http://web4.library.adelaide.edu.au/theses/09PH/09pha315.pdf.
Testo completo
19
Hossain, Mohammad Abul. "Powdery mildew on barley : pathogen variability in South Australia : resistance genes in cv. Galleon /". Title page, contents and abstract only, 1986. http://web4.library.adelaide.edu.au/theses/09PH/09phh8287.pdf.
Testo completo
20
Constable, Fiona Elizabeth. "Biology and epidemiology of Australian grapevine phytoplasmas". Title page, contents and abstract only, 2002. http://web4.library.adelaide.edu.au/theses/09PH/09phc756.pdf.
Testo completo
21
Sing, Sharlene E. "Suppression of bruchids infesting stored grain legumes with the predatory bug Xylocoris flavipes (Reuter) (hemiptera: anthocoridae)". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp04/mq29789.pdf.
Testo completo
22
Taheri, Abdolhossein. "Interaction between root lesion nematode, Pratylenchus neglectus, and root-rotting fungi of wheat". Title page, contents and summary only, 1996. http://web4.library.adelaide.edu.au/theses/09PH/09pht128.pdf.
Testo completoAbstract (sommario):
Bibliography: leaves 307-329. This study concludes that in soils in South Australia where root-rotting fungi and P. neglectus exist together, root disease of wheat is caused by their combined effect. Evidence suggests that P. neglectus not only contributes to this interaction through mechanical wounding of roots, but also causes biochemical and physiological changes in plants, making them more prone to fungal infection.
23
Williams, Mia Gabrielle. "Impact of environmental conditions on the infection behaviour of Western Australian strains of Plasmopara viticola, causal agent of downy mildew in grapevines". University of Western Australia. Soil Science and Plant Nutrition Discipline Group, 2006. http://theses.library.uwa.edu.au/adt-WU2006.0035.
Testo completoAbstract (sommario):
Downy mildew, caused by the biotrophic Oomycete Plasmopara viticola, is one of the most important diseases of grapevines world wide. It is particularly destructive in temperate viticultural regions that experience warm wet conditions during the vegetative growth of the vine (Wong et al., 2001). The disease is not normally a problem in mediterranean climates where the growing season tends to be hot and dry (Mullins et al., 1992; Sivasithamparam, 1993). Grape downy mildew is however a major disease in Australian viticulture (McLean et al., 1984; Magarey et al., 1991). Grape downy mildew was first reported in Europe in 1878 (Viennot-Bourgin, 1981). In Australia, it was recorded for the first time in 1917 at Rutherglen in Victoria (Vic) (de Castella, 1917). The first recorded outbreak of the disease in Western Australia (WA) occurred in 1997 in a small planting of vines in the far north of the state. In the subsequent year, it was detected in widespread commercial viticulture in the Swan Valley production area, near Perth (McKirdy et al., 1999). The pathogen has since been found in all grape growing regions of WA. Since its introduction into European vineyards in the 1880?s, P. viticola has become one of the world?s most investigated grapevine pathogens. Many aspects its basic biology however remain unknown (Wong et al., 2001). Due to the recent detection of P. viticola in WA, little is known of the nature of strains of the pathogen in the state and their response to local environmental conditions. Much of the research concerning the influence of environmental factors on the development of P. viticola has been conducted in Europe e.g. parts of France and Germany. Due to significant differences in climatic conditions and a shorter selection time on the pathogen in WA, much of the information described in European studies may not be directly applicable to the grape downy mildew disease situation in WA. The focus of this thesis was to examine epidemiological aspects of P. viticola in the mediterranean climate of WA. The environmental conditions that could favour the development of epidemics by strains of the pathogen that have been detected in the state were determined. The existence of P. viticola ecotypes and genetic variation among strains from WA and the Eastern states of Australia was also investigated.
24
Lines, Rosemarie. "Development of virus resistant papaya in Australia and Vietnam". Thesis, Queensland University of Technology, 2002.
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25
Trembley, Marcella L. "The effect of mechanical weed cultivation on crop yield and quality, disease incidence and phenology in snap bean, carrot and lettuce crops". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape16/PQDD_0003/MQ29801.pdf.
Testo completo
26
Lucas, Anne. "Water stress and disease development in Eucalyptus marginata (jarrah) infected with Phytophthora cinnamomi". Thesis, Lucas, Anne (2003) Water stress and disease development in Eucalyptus marginata (jarrah) infected with Phytophthora cinnamomi. PhD thesis, Murdoch University, 2003. https://researchrepository.murdoch.edu.au/id/eprint/167/.
Testo completoAbstract (sommario):
The south-west of Western Australia has a Mediterranean climate and flora endemic to this area, including the keystone species, jarrah (Eucalyptus marginata), have adapted to the droughted summer conditions. The introduction of an exotic soil borne pathogen, Phytophthora cinnamomi, has challenged the survival of this and many other species. The expectation might be that plants stressed by drought are more susceptible to disease and this study examined the development of disease caused by P. cinnamomi in E. marginata and the significance of water status to that development.
Seedlings of E. marginata, clonal plants resistant to P. cinnamomi and clonal plants susceptible to P. cinnamomi, were subjected to different watering regimes in a number of field and glasshouse experiments. To determine the level of drought stress that could be imposed on container-grown E. marginata seedlings without killing them, a preliminary experiment progressively lowered the moisture levels of the substrate in their containers, until the plants reached wilting point, at which time moisture was restored to a predetermined droughted level and the process repeated. With each subsequent droughting the wilting point was lower until it was found that the seedlings could survive when only 5% of the moisture lost from container capacity to wilting point was restored.
No deaths had occurred after seedlings had been maintained at this low level for 14 days (Chapter 2). Based on these findings, the level of droughting maintained in all experiments conducted under controlled glasshouse conditions was 10% restoration. After testing the appropriateness of underbark inoculation, and a zoospore inoculation method for which no wounding was necessary, a new, non-invasive stem inoculation technique was developed. Stems were moistened in a pre-treatment, then agar plugs colonized with P. cinnamomi mycelium were held against the stem with wads of wet cotton wool and bound in place with tape. This technique resulted in a high proportion of infection in E. marginata (Chapter 4) without the need for underbark inoculation or the use of zoospores (Chapter 3). It was successfully used in a large field trial in a rehabilitated bauxite mine site with 2-year-old E. marginata clonal plants, resistant to P. cinnamomi (Chapter 5). Inoculation was in late spring after the winter and spring rainfall. This timing was to allow comparison of disease development in stressed plants under normal droughted summer conditions compared with itsdevelopment in non-stressed, irrigated plants. However, two months after inoculation, the area was deluged with unseasonal and abnormally heavy summer rainfall, negating any difference in the treatments and causing an outbreak of P. cinnamomi in the soil from an adjacent infested site. This resulted in the infection and death of some noninoculated control clones.
Monitoring of the site continued for twelve months and the advance of P. cinnamomi at the site was mapped. To test the effect of drought on the expression of P. cinnamomi under more controlled conditions, a series of glasshouse experiments was set up that simulated two possible summer conditions; drought or drought followed by abnormally high summer rainfall. These experiments utilised E. marginata seedlings and clonal plants, some resistant and some susceptible to P. cinnamomi. Plants were inoculated with P. cinnamomi prior to or after droughting. Results were compared to those of control plants that had not experienced water deficit. In both seedlings and clonal plants, the greatest extent of colonization was found in plants which had experienced no water deficit. These results indicated that drought stress played a role in inhibiting the in planta development of P. cinnamomi in all genotypes (Chapter 8). This finding was consistent for both clones, susceptible and resistant to P. cinnamomi. Most recoveries were made from non-stressed clonal plants, resistant to P. cinnamomi (Chapter 6) and more colonization was found in non-stressed clonal plants, susceptible to P. cinnamomi (Chapter 7), than was recorded for droughted plants.
The results of the field trial showed that P. cinnamomi was not recovered from some inoculated stems, which had obvious lesions, when segments were plated onto selective agar. This led to an intensive in vitro investigation into improved methods of recovery. Dark brown exudates from some segments of inoculated stems stained the surrounding agar onto which they were plated, suggesting the presence of phenolic compounds. Recovery of the pathogen from stems increased by about 10% when segments were first soaked in distilled water to leach out the phenolic compounds, then replated onto agar. Other recovery methods were also tested, including (1) baiting with Pimelea ferruginea leaves floated on the surface of water or soil filtrate, in which the infected stem segments were immersed and (2) the application of different light and temperature regimes. It was clearly shown that exudates from infected stems of field grown E. marginata inhibited the outgrowth of P. cinnamomi onto the agar. To counter the possible toxic effect that oxidized phenolics had on the growth of the P. cinnamomi, an antioxidant was added to the agar. P. cinnamomi was grown on media whichincorporated exudates from infected stems and different concentrations of ascorbic acid, with and without adjusted pH levels. There was a pronounced pH effect, with less growth on media with lower pH and no significant increase in growth of the mycelium with increased ascorbic acid concentration on pH adjusted agar (Chapter 9).
The inhibitory effect of the exudates from the stem segments led to an investigation of the possibility that, if seedlings to be planted in the rehabilitation process could be pre-treated with phenolic compounds to render them more resistant, they may have an advantage when establishing in areas where there was a potential threat of P. cinnamomi. E. marginata seeds were germinated and the seedlings grown hydroponically in a constant temperature growth room. Different concentrations of synthetic catechol, a phenolic compound naturally occurring in E. marginata, were added to the nutrient solution. Roots remained immersed in the catechol solutions for three days, before being inoculated at the root tip with zoospores of P. cinnamomi. Roots in higher concentrations of catechol were less colonized than those in lower concentrations, indicating an increased resistance to the pathogen (Chapter 10). Further work is required to determine if seedlings treated before being planted in areas threatened by an outbreak of P. cinnamomi have a greater capacity for survival, and for how long the protection persists.
The improved recovery of P. cinnamomi from infected plants is important for accurate assessment of the spread of the disease in an area and for the subsequent implementation of management strategies of containment and control. An outbreak of P. cinnamomi can impact on the revegetation of rehabilitated mine sites and the aetiology of the pathogen in mine sites needs to be more fully understood. The interaction of plant defences with the invasive pathogen has been examined in a range of environments in the field, the glasshouse, in a hydroponics system and in vitro. The results indicate that summer droughting increases the resistance of E. marginata to P. cinnamomi. However, more work is required to understand the mechanisms involved. The study also indicates that clones of E. marginata, selected as resistant to P. cinnamomi, are not resistant under all conditions and that environmental interactions should be further investigated. Lastly, for effective management strategies to be implemented it is critical that the pathogen can be confidently isolated from plants. It was shown that exudates from infected hosts inhibit the recovery of P. cinnamomi. Recovery methods that can overcome these inhibitory compounds are required. The findings invite further research into the complexity of host-pathogen relationships.
27
Lucas, Anne. "Water stress and disease development in Eucalyptus marginata (jarrah) infected with Phytophthora cinnamomi". Murdoch University, 2003. http://wwwlib.murdoch.edu.au/adt/browse/view/adt-MU20040820.13290.
Testo completo
28
Huang, Chunyuan. "Mechanisms of Mn efficiency in barley". 1996, 1996. http://web4.library.adelaide.edu.au/theses/09PH/09phh8739.pdf.
Testo completoAbstract (sommario):
Bibliography: leaves 131-153. This thesis investigates the mechanisms of manganese (Mn) efficiency (genetic tolerance to Mn-deficient soils) in barley (Hordeum vulgare L.) at both physiological and molecular levels.
29
Geering, Andrew D. W. "The epidemiology of cucumber mosaic virus in narrow-leafed lupins (Lupinus angustifolius) in South Australia". Title page, table of contents and summary only, 1992. http://web4.library.adelaide.edu.au/theses/09PH/09phg298.pdf.
Testo completo
30
Yan, Jwo-Yee. "Studies on the behaviour of males of California red scale Aonidiella aurantii (Maskell)". Title page, contents and summary only, 1985. http://web4.library.adelaide.edu.au/theses/09A/09ay21.pdf.
Testo completo
31
Alfaro, Lemus Ana Lilia. "Factors influencing the control of citrophilous mealybug Pseudococcus calceolarie (Maskell) by Coccophagus gurneyi Compere in the Riverland of South Australia". Title page, contents and abstract only, 2001. http://web4.library.adelaide.edu.au/theses/09IM/09iml562.pdf.
Testo completoAbstract (sommario):
Includes bibliographical references (leaves 102-114) The highly successful biological control of the citrophilous mealybug Pseudococcus calceolarie (Maskell) (CM) by the parasitic wasp Coccophagus gurneyi Compere in several countries led to the release of this parasitoid in the Riverland of South Australia as part of an integrated pest management program. However CM has not been successfully controlled in this region. The results of this study may help to explain the lack of effective biological control of CM in Riverland citrus.
32
Paap, Arie Jacobus. "Development of an optical sensor for real-time weed detection using laser based spectroscopy". Thesis, Edith Cowan University, Research Online, Perth, Western Australia, 2014. https://ro.ecu.edu.au/theses/1282.
Testo completoAbstract (sommario):
The management of weeds in agriculture is a time consuming and expensive activity, including in Australia where the predominant strategy is blanket spraying of herbicides. This approach wastes herbicide by applying it in areas where there are no weeds. Discrimination of different plant species can be performed based on the spectral reflectance of the leaves. This thesis describes the development of a sensor for automatic spot spraying of weeds within crop rows. The sensor records the relative intensity of reflected light in three narrow wavebands using lasers as an illumination source.
A prototype weed sensor which had been previously developed was evaluated and redesigned to improve its plant discrimination performance. A line scan image sensor replacement was chosen which reduced the noise in the recorded spectral reflectance properties. The switching speed of the laser sources was increased by replacing the laser drivers. The optical properties of the light source were improved to provide a more uniform illumination across the viewing area of the sensor. A new opto-mechanical system was designed and constructed with the required robustness to operate the weed sensor in outdoor conditions. Independent operation of the sensor was made possible by the development of hardware and software for an embedded controller which operated the opto-electronic components and performed plant discrimination.
The first revised prototype was capable of detecting plants at a speed of 10 km/h in outdoor conditions with the sensor attached to a quad bike. However, it was not capable of discriminating different plants. The final prototype included a line scan sensor with increased dynamic range and pixel resolution as well as improved stability of the output laser power. These changes improved the measurement of spectral reflectance properties of plants and provided reliable discrimination of three different broadleaved plants using only three narrow wavelength bands. A field trial with the final prototype demonstrated successful discrimination of these three different plants at 5 km/h when a shroud was used to block ambient light.
A survey of spectral reflectance of four crops (sugarcane, cotton, wheat and sorghum) and the weeds growing amongst these crops was conducted to determine the potential for use of the prototype weed sensor to control spot-spraying of herbicides. Visible reflectance spectra were recorded from individual leaves using a fibre spectrometer throughout the growing season for each crop. A discriminant analysis was conducted based on six narrow wavebands extracted from leaf level spectral reflectance measured with a spectrometer. The analysis showed the potential to discriminate cotton and sugarcane from
33
Dennis, Jeremy Ian. "Chocolate spot of faba beans in South Australia". Thesis, 1991. http://hdl.handle.net/2440/109036.
Testo completoAbstract (sommario):
Entry of inoculum into a crop and disease development in the crop cannot be prevented because spores are airborne and there is a lack of highly resistant varieties. This makes complete control of chocolate spot unlikely. It should however, be possible to improve current levels of disease control through the integration of the factors identified in the studyThesis (M.Ag.Sc.) -- University of Adelaide, Departments of Plant Science and Crop Protection, 1991
34
Boudreau, Mark Alan 1958. "Effects of intercropping beans with maize on angular leaf spot and rust of beans". Thesis, 1991. http://hdl.handle.net/1957/36577.
Testo completoAbstract (sommario):
Experiments were performed to determine the nature of
maize influence on bean disease in additive-type
intercrops. Overall effects of intercrops on angular leaf
spot (caused by Phaeoisariopsis griseola) in Kenya
indicated >23% reductions (P<0.05) in area under the
disease progress curve (AUDPC) in two of three season-site
combinations. Fertilization tended to increase disease
(135-205%, P<0.10), but changes in bean density or planting
pattern had no effect. Intercrops reduced temperature and
wind velocity, but increased relative humidity. A 27%
AUDPC reduction (P=0.07) in bean rust (caused by Uromyces
appendiculatus) due to intercropping was observed in Oregon
in 1989 and 1990 in two of three locations.
Mechanisms of maize influence on rust were also
assessed in Oregon. Intercropping, and competition of
maize with beans alone, consistently steepened dispersal
gradients (P<0.10). Interference of maize with dispersal
alone tended to flatten gradients. Spore retention in
plots was increased in mid-season, then decreased late in
the season, due to competition in both years (P<0.05).
Intercropping reduced infection by 96% late in 1989
(P<0.05), probably due to microclimatic influence of maize.
The data from these experiments were used as inputs
for computer simulation to evaluate effects of specific
mechanisms on disease dynamics. Combination of all
mechanisms (= intercrop) reduced AUDPC to 32% of monocrop,
using 1989 data. Infection efficiency reductions, and to a
lesser extent dispersal effects, were responsible for these
changes. Intercrop effects declined as pathogen
multiplication rate (DMFR) increased. No intercrop effect
occurred at any DMFR using 1990 data, although interference
and competition effects of maize alone both increased AUDPC
at low DMFR. Partitioning dispersal effects into those due
to gradient slope changes and spore retention indicate that
the latter accounts almost entirely for disease alteration.Graduation date: 1992
35
Lawsawadsiri, Somporn. "Variation in resistance to Ascochyta blight in faba beans / Somporn Lawsawadsiri". Thesis, 1994. http://hdl.handle.net/2440/18502.
Testo completo
36
Pratt, Paul D. (Paul David) 1970. "Within and between plant dispersal and distributions of adult females and immatures of Neoseiulus californicus and N. fallacis (Acari: Phytoseiidae) in bean and apple plant systems". Thesis, 1997. http://hdl.handle.net/1957/34940.
Testo completoAbstract (sommario):
Intra- and interplant movement and dispersal of the predator mites Neoseiulus californicus (McGregor) and Neoseiulus fallacis (Garman) were studied on both lima bean (Phaseolus lunatus L.) and apple (Malus pumila Miller) branch plant systems that were seeded with excess numbers of the spider mite Tetranychus urticae Koch. Individuals of either predator were randomly selected from colonies of well-fed, mixed-age adult females and moved to test plants. When tested separately in each plant system, median leaf positions of N. californicus from the point of release were greater than those of N. fallacis at 1-8 d. A fan placed in front of a common source unit (1x3m) containing T. urticae and near equal densities of both predaceous mites, provided continuous air (wind) to 3 isolated receiver units located 2.5, 5, and 7.5 m downwind. Receiver units consisted of continuous bean foliage with excess T. urticae, but no predators. Wind speeds at the source and each receiver unit averaged 2.2, 0.9, 0.4, and 0.03 m/s respectively. As predators eliminated prey, N. fallacis dispersed earlier at higher prey densities and further downwind than N. californicus, but cumulative densities of each predator in all receiver units were alike after 20 d. Results of both plant movement studies supported the hypothesis that N. californicus has dispersal traits more like those of a generalist predator of spider mites than does N. fallacis. Spatial patterns of dispersal and biological control of pest mites are discussed in relation to predation types within the Phytoseiidae.Graduation date: 1997
37
Tynan, K. M. (Kim Michelle). "Evaluation of Banksia species for response to Phytophthora infection". 1994. http://web4.library.adelaide.edu.au/theses/09PH/09pht987.pdf.
Testo completo
38
Xu, Ling 1963. "Serological and molecular approaches for distinguishing bean common mosaic and bean common mosaic necrosis potyviruses and their respective pathogroups". Thesis, 1995. http://hdl.handle.net/1957/34991.
Testo completoAbstract (sommario):
Polyclonal antisera were raised against isolates of bean
common mosaic virus (BCMV) and bean common mosaic necrosis
virus (BCMNV) using conventional serological methods.
Infected tissues containing, respectively, 22 recognized BCMV
and BCMNV isolates were tested against the two antisera by
antigen-coated plate (ACP) ELISA and double antibody sandwich
(DAS) ELISA. Results indicated that each immunoglobulin was
virus-specific by DAS-ELISA, providing clear distinction
between BCMV and BCMNV.
A reverse transcription, polymerase chain reaction (RT-PCR)-based assay in combination with restriction endonuclease
analyses, was developed for molecular detection of BCMV, BCMNV
and their pathogroups. Specific detection of the two viruses
was accomplished by constructing two virus-specific primer
pairs that amplified a PCR product specific for each virus.
Distinction of two BCMNV pathogroups (PG-III and PG-VI) was
achieved by restriction enzyme XbaI digestion of BCMNV PCR
products. However, none of the tested restriction enzymes
clearly differentiated the five recognized BCMV pathogroups.
A primer pair Dts/Uny15 specific for BCMV pathogroup V was
also developed. By its RT-PCR application, four BCMV-PG-V
isolates were differentiated from the other known variants of
BCMV pathogroup I, II, IV and VII. Thus, by a combination of
RT-PCR and restriction enzyme analyses, it was possible to
differentiate both viruses, and two pathogroups of BCMNV, and
one pathogroup of BCMV.Graduation date: 1996
39
Ferguson, Kaye. "The biology, ecology and management of the Quandong moth, Paraepermenia santaliella (Lepidoptera: Epermeniidae) / by Kaye Louisa Ferguson". Thesis, 2001. http://hdl.handle.net/2440/21957.
Testo completoAbstract (sommario):
Includes bibliographical references (leaves 217-230).230 leaves : ill. (some col.) ; 30 cm.
Details the biology and life history of the Quandong moth and investigates management strategies that would enable growers to manage the pest in an economically and environmentally sustainable program.
Thesis (Ph.D.)--University of Adelaide, Dept. of Applied and Molecular Ecology, 2001
40
Fourie, Deidre. "Bacterial diseases of dry beans in South Africa with special reference to common bacterial blight and its control". Thesis, 2003. http://hdl.handle.net/2263/25946.
Testo completo
41
Landsberg, Jennifer Jill. "Dieback of rural eucalypts : dietary quality of foliage and insect herbivory". Phd thesis, 1986. http://hdl.handle.net/1885/143177.
Testo completo
42
Barr, Andrew R. (Andrew Robert). "Strategies for the control of the foliar diseases of oats in South Australia". 1994. http://web4.library.adelaide.edu.au/theses/09PH/09phb268.pdf.
Testo completo
43
Evans, Katherine J. "Characterization of Uncinula necator, the grapevine powdery mildew fungus / Katherine J. Evans". Thesis, 1996. http://hdl.handle.net/2440/18727.
Testo completoAbstract (sommario):
Bibliography: leaves 148-166.vi, 169, [4] leaves, [20] leaves of plates : ill. (some col.) ; 30 cm.
This study identifies genetic variation in Australian Uncinula necator populations. Techniques were developed for molecular and phenotypic markers for U. necator. Mating types of Australian clonal lines were identified and viable cleistothecia and infective ascospores were produced in vitro. The study establishes the foundation for investigating the population biology of U. necator, by identifying two distinct genetic groups, A and B, and micro-geographical variation among 35 clonal lines from various Australian viticultural regions.
Thesis (Ph.D.)--University of Adelaide, Dept. of Crop Protection, 1996
44
Barr, Andrew Robert. "Strategies for the control of the foliar diseases of oats in South Australia / by Andrew R. Barr". 1994. http://hdl.handle.net/2440/21584.
Testo completoAbstract (sommario):
Bibliography: p. 410-429.429 p., [20] leaves of plates : ill. (some col.), map ; 30 cm.
Title page, contents and abstract only. The complete thesis in print form is available from the University Library.
Thesis (Ph.D.)--University of Adelaide, Dept. of Plant Science, 1995?
45
Barr, Andrew Robert. "Strategies for the control of the foliar diseases of oats in South Australia / by Andrew R. Barr". Thesis, 1994. http://hdl.handle.net/2440/21584.
Testo completo
46
Hosseini, Reza. "A DNA-based approach to study predator-prey trophic interactions within Brassica crops : a search for predators of diamondback moth (Plutella xylostella)". 2007. http://hdl.handle.net/2440/56816.
Testo completoAbstract (sommario):
Title page, contents and abstract only. The complete thesis in print form is available from the University of Adelaide Library.Brassica vegetables and oilseeds are economically important crops worldwide. These crops are associated with several destructive and widespread insect pests. In Australia these pests include six species, Plutella xylostella (Linnaeus), Pieris rapae (Linnaeus), Hellula hydralis Guenée, Helicoverpa punctigera (Wallengren), Brevicoryne brassicae (Linnaeus) and Myzus persicae (Sulzer), which are the focus of this research. Among them P. xylostella (diamondback moth or DBM) is the most serious and destructive insect pest. Little is known about the potential of predators, which may be able to contribute to control diamondback moth, although some field studies have shown the overall importance of predators in controlling this key pest. The aim of this study was to develop a method that allows study of predator-prey trophic interactions in the field.
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Thesis (Ph.D.) -- University of Adelaide, School of Agriculture, Food and Wine, 2007
47
Crisp, Peter. "Sustainable control of grapevine powdery mildew (Uncinula necator Schweinitz Burrill) in vineyards in South Australia". 2004. http://hdl.handle.net/2440/59636.
Testo completoAbstract (sommario):
Title page, table of contents and abstract only. The complete thesis in print form is available from the University of Adelaide Library.Grapevine powdery mildew, caused by the fungus Uncinula necator Schweinitz Burrill, is a major disease affecting grape yield and quality worldwide. In conventional vineyards, the disease is controlled mainly by regular applications of sulphur and synthetic fungicides, such as demethylation inhibiting fungicides (DMIs), and in organic agriculture by sulphur and canola-based oils. The impending restrictions on the use of sulphur in organic viticulture, the development of resistance to DMls in Australia and elsewhere, and the demand for residue-free grapes create a need for effective alternatives to sulphur and synthetic chemicals. This research has identified potential replacements for synthetic fungicides and sulphur in the control of powdery mildew, such as milk, whey, bicarbonates and canola oil-based sprays. A series of greenhouse experiments was conducted to evaluate 34 potential novel materials and biological agents for efficacy in controlling powdery mildew. The most effective treatments applied were Bacillus subtilis (which reduced disease by 94% compared to the untreated control), Synertrol Horti-Oil® (a canola oil-based product, 92%), milk (70%), whey (64%) and Ecocarb® (potassium bicarbonate, 58%). Milk and whey provided increased control of powdery mildew as the concentration increased. The efficacy of milk tended to decrease as the fat content of the milk was reduced. The materials that were most promising in the greenhouse were then assessed in field trials in commercial vineyards. Applications of milk, whey and mixtures of a canola oil-based product and potassium bicarbonate, applied at rates of 300 L/ha to 1000 L/ha depending on canopy development, reduced the severity of powdery mildew. The severity of powdery mildew on vines sprayed with a 1:10 dilution of milk, 45 g/L whey powder and mixed programs was not significantly different from that on vines sprayed with sulphur (wettable powder, 3 g/L). However, the relative control of powdery mildew by the test materials in field trials was highly dependent on the degree of coverage of the plant surface achieved. In vineyards where coverage was compromised, the degree of control of powdery mildew was reduced, often to commercially unacceptable levels. Electron spin resonance (ESR) and scanning electron microscopy (SEM) were used to investigate the possible mode or modes of action of milk and whey in the control of powdery mildew. The ESR experiments showed that production of oxygen radicals by various components of milk in natural light was associated with reduced severity of powdery mildew. SEM images showed that milk and whey caused the hyphae of U necator to collapse and damaged conidia within 24 h of treatment. Hydrogen peroxide, applied as a source of free radicals, also caused collapse of the hyphae of U necator within 24 h but did not damage conidia, and appeared to stimulate germination. Lactoferrin (an antimicrobial component of milk) ruptured conidia, but damage to hyphae was not evident in lactoferrin-treated samples until 48 h after treatment. The results suggested that fats, free radical production along with the action of lactoferrin, and possibly other proteins, are associated with the control of powdery mildew by milk. Novel soft fungicides, such as milk and oil plus bicarbonate mixtures, were effective alternatives to sulphur and synthetic fungicides in certain South Australian conditions. Biological agents (including B. subtilis, which was highly effective in greenhouse experiments) did not provide acceptable control of powdery mildew in the vineyard.
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Thesis (Ph.D.) -- University of Adelaide, School of Agriculture and Wine, 2004
48
Crisp, Peter. "Sustainable control of grapevine powdery mildew (Uncinula necator Schweinitz Burrill) in vineyards in South Australia". Thesis, 2004. http://hdl.handle.net/2440/59636.
Testo completoAbstract (sommario):
Grapevine powdery mildew, caused by the fungus Uncinula necator Schweinitz Burrill, is a major disease affecting grape yield and quality worldwide. In conventional vineyards, the disease is controlled mainly by regular applications of sulphur and synthetic fungicides, such as demethylation inhibiting fungicides (DMIs), and in organic agriculture by sulphur and canola-based oils. The impending restrictions on the use of sulphur in organic viticulture, the development of resistance to DMls in Australia and elsewhere, and the demand for residue-free grapes create a need for effective alternatives to sulphur and synthetic chemicals. This research has identified potential replacements for synthetic fungicides and sulphur in the control of powdery mildew, such as milk, whey, bicarbonates and canola oil-based sprays.
A series of greenhouse experiments was conducted to evaluate 34 potential novel materials and biological agents for efficacy in controlling powdery mildew. The most effective treatments applied were Bacillus subtilis (which reduced disease by 94% compared to the untreated control), Synertrol Horti-Oil® (a canola oil-based product, 92%), milk (70%), whey (64%) and Ecocarb® (potassium bicarbonate, 58%). Milk and whey provided increased control of powdery mildew as the concentration increased. The efficacy of milk tended to decrease as the fat content of the milk was reduced.
The materials that were most promising in the greenhouse were then assessed in field trials in commercial vineyards. Applications of milk, whey and mixtures of a canola oil-based product and potassium bicarbonate, applied at rates of 300 L/ha to 1000 L/ha depending on canopy development, reduced the severity of powdery mildew. The severity of powdery mildew on vines sprayed with a 1:10 dilution of milk, 45 g/L whey powder and mixed programs was not significantly different from that on vines sprayed with sulphur (wettable powder, 3 g/L). However, the relative control of powdery mildew by the test materials in field trials was highly dependent on the degree of coverage of the plant surface achieved. In vineyards where coverage was compromised, the degree of control of powdery mildew was reduced, often to commercially unacceptable levels.
Electron spin resonance (ESR) and scanning electron microscopy (SEM) were used to investigate the possible mode or modes of action of milk and whey in the control of powdery mildew. The ESR experiments showed that production of oxygen radicals by various components of milk in natural light was associated with reduced severity of powdery mildew. SEM images showed that milk and whey caused the hyphae of U necator to collapse and damaged conidia within 24 h of treatment. Hydrogen peroxide, applied as a source of free radicals, also caused collapse of the hyphae of U necator within 24 h but did not damage conidia, and appeared to stimulate germination. Lactoferrin (an antimicrobial component of milk) ruptured conidia, but damage to hyphae was not evident in lactoferrin-treated samples until 48 h after treatment. The results suggested that fats, free radical production along with the action of lactoferrin, and possibly other proteins, are associated with the control of powdery mildew by milk.
Novel soft fungicides, such as milk and oil plus bicarbonate mixtures, were effective alternatives to sulphur and synthetic fungicides in certain South Australian conditions. Biological agents (including B. subtilis, which was highly effective in greenhouse experiments) did not provide acceptable control of powdery mildew in the vineyard.Thesis (Ph.D.) -- University of Adelaide, School of Agriculture and Wine, 2004
49
Marte, Susan Plantier, University of Western Sydney, College of Health and Science e Centre for Plant and Food Science. "Fruit-tree borer (Maroga melanostigma) : investigations on its biological control in prune trees". 2007. http://handle.uws.edu.au:8081/1959.7/31976.
Testo completoAbstract (sommario):
Fruit-tree borer, Maroga melanostigma (Wallengren), is a native Australian pest in many species of trees. It is of particular economic importance in prune (Prunus domestica) trees because the presence of this wood boring insect can reduce productivity by an average of 5% per tree. Large areas of orchards can be affected. There are currently no chemicals registered for control of this pest. Young, New South Wales is the second largest prune-growing district in Australia and the area most seriously affected by M. melanostigma. Prune growers in the district utilise integrated pest management and were supportive of a project to investigate biological control options for this economically damaging pest. The two main objectives of the project were 1) to understand the life cycle of M. melanostigma, so biological controls could be timed appropriately; and 2) to investigate biological control options for this pest. Life cycle studies were commenced in the first season (2003/04) using field cages and light trapping. These investigations continued throughout the project. In Young, moths were found to emerge from wood over a two month period (December and January). Oviposition was assumed to be during this period however, even after extensive searches of trees, no eggs were observed. Historical data were collated to determine locations and timings of moth emergence elsewhere in Australia. The data showed that M. melanostigma has been found in every state and territory Australia, with moths observed from October through to March. The biological control options reviewed were egg parasitoids (Trichogramma species only), entomopathogenic nematodes and entomopathogenic fungi. Trichogramma were favoured because of previous research undertaken against the same pest in pecans in Moree, NSW. Entomopathogenic nematodes were also investigated due to research indicating their effectiveness in cryptic situations, such as borer tunnels in trees. Fungi were considered but dismissed due to lack of literature supporting their effectiveness in reducing lepidopteran pest damage in trees. A major field trial was designed with the assistance of a biometrician and the trial blocks laid out based on this advice. There were three trial sites, each containing four blocks of approximately 200 trees (~800 trees/site). Two blocks were designated as release blocks and two as non-release blocks to correspond with the trial’s two treatments. In the first season (2003/04) an initial visual assessment of borer damage was undertaken after leaf fall on each of the trees in the trial. This information was used as baseline data, to compare against damage levels following biological control releases in the second and third years of the project. Natural parasitism in the field was assessed using cultured eggs of Helicoverpa armigera (Hübner) before and between Trichogramma carverae (Oatman and Pinto) releases. Temperature and relative humidity were recorded in each of the trial sites, for the duration of the trial, using commercially available data loggers. In the second season (2004/05), Trichogramma releases were made during the period of moth activity and H. armigera eggs were used to monitor parasitism in the trial orchards. Parasitised eggs were reared through and all parasitoids were identified as T. carverae. Damage assessments were again carried out after leaf fall to compare release versus non-release blocks, as well as to determine if there was any change in borer activity. Early instar larvae were collected from non-trial blocks and exposed to the entomopathogenic nematode Steinernema carpocapsae in a laboratory investigation. Results from this limited bioassay were inconclusive. In the third season (2005/06), Trichogramma releases were again made during the period of moth activity and H. armigera eggs were used to monitor parasitism in the trial orchards. Parasitised eggs were reared through to emergence. The emerged parasites were identified as T. carverae, T. pretiosum and T. nr brassicae. Damage assessments were again made of all the trees in the trial. Results were statistically analysed to detect any differences between treatments. There was no statistically significant evidence that the releases of T. carverae reduced damage from M. melanostigma over the duration of the trial. Although damage increased across both release and non-release treatments in most blocks during the trial investigations, the increase was slightly lower in trees in which Trichogramma had been released. It should be noted that the experiments were affected by serious drought conditions which prevailed during the three seasons of the trial.Master of Science (Hons)
50
Njoki, Ng'ayu-Wanjau Beatrice. "Breeding for durable resistance to angular leaf spot (Pseudocercospora griseola) in common bean (Phaseolus vulgaris) in Kenya". Thesis, 2014. http://hdl.handle.net/10413/10701.
Testo completoAbstract (sommario):
Common bean (Phaseolus vulgaris L.) is an important legume crop in Kenya and is a cheap source of proteins. The small scale farmers in Kenya produce common bean under low agricultural input systems and this predisposes the crop to pests and diseases. Among the diseases, angular leaf spot (ALS) is a major constraint to common bean production and contributes to yield losses as high as 80%. The causative pathogen Pseudocercospora griseola (Sacc.) Crous & Braun is highly variable and several races have been reported. There are few common bean genotypes with resistance to this disease. Therefore breeding for resistance to ALS is important for the country. This study was carried out to; i) evaluate the common bean production systems, constraints and farmer varietal preferences in Kenya, ii) evaluate local landraces and selected introductions of common bean for yield performance and reaction to ALS, iii) study the genetics of resistance to ALS in common bean and iv) develop a breeding method for durable resistance to ALS in common bean.
To determine the common bean production systems, farmers’ preferred traits and their knowledge on common bean constraints including ALS, a survey was conducted in Kiambu county using a semi-structured questionnaire, interviews, and focus group discussions. The study revealed that farmers cultivate common beans during the short and long rain seasons. However, they experience better yields in the short rains due to reduced disease incidence. The majority of the farmers (71%) intercrop common bean and this ensures maximum utilisation of space. A high percentage (70%) of the farmers utilise their retained seed for production. The farmers identified ALS as one of the most important constraints to production. The only preventative measure they undertake to control the disease is weeding. The farmers reported that they would prefer improved varieties that were resistant to ALS. Farmers have a preference for particular common bean traits that include high yield (80%), resistance to insect-pests and diseases (72%), type I growth habit (52%), early maturity (68%), seed size and colour (21%) and cooking time (20%). These should be incorporated in breeding programmes.
Two hundred common bean landraces and market class varieties were evaluated for ALS resistance in a nethouse at University of Nairobi, Kabete Field Station and for ALS resistance and yield in the field in KARI-Tigoni. The results showed that disease severity scores for the genotypes were similar in the two locations, with the top three resistant genotypes being Minoire, GBK 028123 and Murangazi with disease severity scores of 2.9, 2.9 and 3.2 in Kabete
and 2.6, 2.8, and 2.9 in Thika respectively. These resistant genotypes can be used as sources of resistance in a breeding programme or they can be used as resistant varieties. All the market class varieties were susceptible to ALS (disease severity score 6.7-8.0). There was a non-significant correlation between disease and yield most likely because most of the resistant genotypes were exotic and hence not adapted to the local conditions. There was also a non-significant correlation between disease and seed size.
The two hundred common bean genotypes were evaluated for yield at University of Nairobi, Kabete Field Station and KARI-Thika. The results indicated that the 2011 and 2012 seasons had similar mean yields and that yields at Kabete were higher than at KARI-Thika. The highest yielding genotypes across the two locations were; GLP 2 (766 kg ha-1), Nyirakanyobure (660 kg ha-1), GBK 028110 (654 kg ha-1), GLP 585 (630 kg ha-1) and Mukwararaye (630 kg ha-1). There was a significant genotype x environment interaction and hence it is important for breeders to carry out stability analysis, so as to recommend varieties for a wide range of environments.
To study the genetics of ALS resistance in common bean, three inter-gene pool crosses: Super-rosecoco x Mexico 54, Wairimu x G10909 and Wairimu x Mexico 54 were made. The resistant genotypes were Mexico 54 and G10909, while Super-rosecoco and Wairimu were susceptible. The generations F1, F2, BC1P1 and BC1P2 for each of the crosses were developed. The parents P1, P2 and the five generations of each cross were evaluated for resistance to ALS in Kabete Field Station. Results showed that both dominance and additive gene action were important in the expression of resistance to ALS. However, additive gene action was predominant over dominance gene action. There was a moderately high narrow sense heritability estimate (52.9-71.7%). The minimum number of genes controlling resistance to ALS was between 2 and 3. The predominance of additive gene effects and the moderately high narrow sense heritability estimates recorded imply that progress in resistance to ALS could be made through selection in the early segregating generations.
A double cross followed by selection against resistant genotypes was used to develop a method to breed for durable resistance to ALS in common bean. The method was used to accumulate minor genes of ALS resistance into single genotypes. Four intermediate resistant landraces were used to develop a double cross population that was screened using a mixture of ALS races. Selection in F1 and F2 population was done on the basis of intermediate resistance (disease severity score 4.0-6.0), while selection from F3 population was based on resistance
(disease severity score 1.0-3.0). Ten advanced F4 lines along with their parents were evaluated for ALS resistance. The F4 advanced lines had a significantly improved resistance to ALS compared to their parents. Hence the method was successful in accumulating minor genes for resistance thus showing significant breeding progress in breeding for durable resistance.Thesis (Ph.D.)-University of KwaZulu-Natal, Pietermaritzburg, 2013.