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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.
61

Aspectos vegetativos e produtivos de cultivares copa de pereira europeia com combinações de porta enxertos / Vegetative and productive aspects of european pear scions cultivars in combination with rootstocks

Machado, Bruno Dalazen 18 July 2011 (has links)
Made available in DSpace on 2016-12-08T16:44:40Z (GMT). No. of bitstreams: 1 PGPV11MA090.pdf: 2054510 bytes, checksum: 32647b7dea5bdc407d1fddadc50c5cc7 (MD5) Previous issue date: 2011-07-18 / Conselho Nacional de Desenvolvimento Científico e Tecnológico / This study aimed to evaluate the vegetative and productive aspects os European pear cultivars, grafted on three rootstocks of quince, as well as the behavior of different combinations in the environmental conditions of the regions under study. The experiments were conducted in the experimental areas of Agrícola Fraiburgo S/A located in the city of urupema, SC (altitude 1425 m) and Fischer fraiburgo, located in the city of Fraiburgo, SC (altitude 1048 m). The experiment was evaluated in 2008/09 seasons. The cultivars evaluated were Packham s Triumph, santa Maria, Conference, Rocha, Decana du comice, Abbè Fetel, Clapp s Favourite and William s and quince rootstocks EMA, EMC, and Adams. Each scion-rootstock combination were planted 4 m between-row spacing and 0,3 m, 0,5 m, and 1m within-row. To evaluate plant vigour was measure plant height (m), canopy volume (m3); diameter of the trunk diameter of scion and rootstock of the trunk of cv. Scion (mm) Diameter of the trunk of rootstock (mm), difference between the trunk diameter of scion and rootstock (mm), index of fertility (buds cm-1). Total weight of pruned branches (kg), difference between the fresh weight and dry weight of pruned branches (kg), leaf area (cm2) and chlorophyll content (SPAD unit). To evaluate the productive aspects, measuring the number of fruits per plant, estimated productivity (kg ha -1), productive efficiency (kg m-3). Production per plant (kg plant-1), Profitability (R$) chemical and physical characteristics of the fruit, as fruit diameter (mm), firmness (kg cm-2), soluble solids (˚Brix) and titratable acidity (meq L-1). The combination Abbe Fetel/Adams willing to 1 and 0,3 m between plants and Packham s Triumph on EMA to 0,5 m, provide greater vigour. The cv. Clapp s Favourite grafted on quince EMA prints reduced vigour. The cv. Clapp s Favourite grafted on quince EMA, showed reduced vigour. Plants with greater trunk diameter, canopy had higher growth and greater vigour. The cvs. Conference and William s when grafted to quince EMC showed morphological signs of incompatibility. With respect to the productive aspects, combinations Packham1s Triumph/Addams to 1 m spacing, Rocha/EMC to 0,5 m Santa Maria/Addams to 0,3 m, were more efficient and profitable production, with a estimated yield (6,8 t ha-1), (5,9 t ha-1) and (19,7 t ha-1) respectively. The fruits of larger diameter ghadlower firmness / O presente trabalho teve como objetivo, avaliar os aspectos vegetativos e produtivos de cultivares copa de pereiras europeias, enxertadas sobre três porta enxertos de marmeleiro, assim como o comportamento das diferentes combinações nas condições edafoclimáticas das regiões em estudo. Os experimentos foram conduzidos nas áreas experimentais das empresas Agrícola Fraiburgo S/A, localizada no município de Urupema, SC (altitude 1425 m) e Fischer S.A. Agroindústria, localizada no município de Fraiburgo, SC (altitude 1048 m). As plantas encontram-se na segunda folha e o sistema de condução utilizado foi o líder central. O experimento foi avaliado nas safras 2008/09, 2009/10 e 2010/11. Foram utilizadas as cultivares Packham‟s Triumph, Santa Maria, Conference, Rocha, Decana du Comice, Abbè Fetel, Clapp‟s Favourite e William‟s e os porta enxertos de marmeleiro EMA, EMC e Adams. Os espaçamentos de plantio utilizados foram de 4 m entre filas e 0,33 m, 0,5 m e 1 m entre plantas. Para avaliar o vigor foi mensurado: incremento de altura de plantas (m), incremento de volume de copa (m3), incremento de diâmetro do tronco da cv. copa (mm), incremento de diâmetro do tronco do porta enxerto, diferença de diâmetro entre a cultivar copa e o porta enxerto (mm), índice de fertilidade (no de gemas cm-1), peso de poda de inverno (Kg), diferença entre a massa fresca e a massa seca dos ramos podados (Kg), área foliar folha-1 (cm2) e teor de clorofila (unidades SPAD). Para avaliar os aspectos produtivos, mensurou-se o o número de frutos por planta (n0 frutos pl-1), produtividade estimada (Kg ha -1), rentabilidade (R$), eficiência produtiva (Kg m-3), produção por planta (Kg planta-1), diâmetro do fruto (mm), firmeza de polpa (Kg cm-2), sólidos solúveis (oBrix) e acidez titulável (meq L-1). A combinação Abbè Fetel/Adams disposta a 1 e 0,3 m entre plantas e Packham‟s Triumph sobre EMA a 0,5 m, propiciam alto vigor às plantas. A cv. Clapp‟s Favourite enxertada sobre marmeleiro EMA imprime reduzido vigor. Maiores sinais de incompatibilidade morfológica são observados nas cvs. Conference e William‟s quando enxertadas com o marmeleiro EMC. Com relação aos aspectos produtivos, as combinações Packham‟s Triumph/Adams no espaçamento de 1 m, Rocha/EMC a 0,5 m e Santa Maria/Adams a 0,3 m, são mais eficientes em termos produtivos e rentáveis, com produtividade estimada de (6,8 t ha-1), (5,9 t ha-1) e (19,7 t ha-1) respectivamente. Os frutos de maior diâmetro obtiveram menor firmeza de polpa
62

Testes de envelhecimento acelerado e análise computadorizada de imagens de plântulas para avaliação do desempenho de sementes de soja durante o armazenamento / Accelerated aging tests and automated computer imaging system to assess the performance of soybean seeds during storage

Juliana Tieme Yagushi 25 January 2012 (has links)
A avaliação adequada do potencial fisiológico de sementes de soja pode auxiliar as empresas produtoras na tomada de decisões importantes, como a escolha dos lotes a serem armazenados e a definição das condições mais favoráveis à manutenção do nível de desempenho satisfatório das sementes. Neste contexto, o trabalho foi conduzido com objetivo de verificar a eficiência dos testes de envelhecimento acelerado (tradicional e com solução saturada de NaCl) e do SVIS® para avaliar o potencial fisiológico e estimar o potencial de armazenamento de sementes de soja, em comparação com testes recomendados para sementes dessa espécie. Foram utilizadas sementes dos cultivares BRS 184 e M-Soy 7908 RR, cada um representado por seis lotes, armazenados por seis meses em dois ambientes: controlado (20 ºC e 75 % de UR do ar) e de laboratório. O desempenho das sementes foi verificado a cada dois meses durante o armazenamento, por meio de avaliações de germinação, envelhecimento acelerado, condutividade elétrica, tetrazólio, emergência de plântulas em areia e análises SVIS®. Verificou-se que o teste de envelhecimento acelerado (tradicional e com solução saturada de NaCl) e o sistema computadorizado de análise de imagens de plântulas (SVIS®) são eficientes para avaliação do potencial fisiológico de sementes armazenadas de soja. O potencial de armazenamento de sementes de soja é avaliado, com segurança, pela associação dos testes de germinação e de vigor, incluindo o envelhecimento acelerado (tradicional e com solução saturada de NaCl) e as análises SVIS®. / The evaluation of soybean seed vigor has been helping the seed industry in important decisions such as choice of lots to be stored and to defining the appropriate conditions for storability.The objective of this study was to verify the accuracy of accelerated aging tests (traditional and with saturated NaCl) and automated system for seedling evaluation (SVIS®) to assess the physiological potential and estimate the storability of soybean seeds in comparison to the information from accept vigor tests for this species. Two cultivars BRS 184 and M-Soy 7908 RR, each represented by six lots were used. Seeds were stored for six months under two environments: controlled (20ºC and 75% relative air humidity) and normal conditions. Seed performance was evaluated in two month intervals by germination, accelerated aging, electrical conductivity, tetrazolium, SVIS® and sand seedling emergence. Results indicated that accelerated aging (traditional and with saturated NaCl) and automated computer imaging of seedlings (SVIS®) are effective for evaluating the physiological potential of soybean seeds. The storability of soybeans seeds can be consistently evaluated by associating germination and vigor test results, including accelerated aging (traditional and with saturated NaCl) and SVIS®.
63

Qualidade fisiológica de sementes de cevada influenciadas pela época de colheita / Barley harvesting time delay on the physiological quality of seeds

Silva, Airam Fernandes da 18 April 2007 (has links)
Made available in DSpace on 2014-08-20T13:44:41Z (GMT). No. of bitstreams: 1 dissertacao_airam_fernandes_silva.pdf: 244807 bytes, checksum: f4a5a83a76eb60a4db318853ffd20a6b (MD5) Previous issue date: 2007-04-18 / The purpose of this work was to verify the physiologic quality of seeds of two barley cultivars, in different harvesting times. The experiment was installed in a field of barley production for brewing industry, in Piratini, RS during 2006 growing season. The analyzed seeds were cultivar MN858 and SCARLETT, harvesting starts when panicles were with a moisture around 30% (physiologic maturation) and subsequent harvesting in regular intervals of ten days. To determine the physiologic quality of the seeds the following variables were accomplished: germination; first counting of germinated seeds; tetrazolium; accelerated aging; weight of one thousand seeds; hectoliter weight; lenght of the aerial and root systems; dry and fresh matter of root and aerial systems; and electrical conductivity. The experimental design used was an entirely randomized with four replications and the means were compared by Duncan multiple ranger test (5% of significance). It was concluded that barley cultivars studied, have dormancy just after harvested; with harvesting time delay, cultivar MN858 increases, intensely, dormancy, while, in cultivar SCARLETT, dormancy tends to decrease; seeds of cultivar MN858 presents better physiologic quality when harvested with a moisture of 22,8%, while in cultivar SCARLETT, with a moisture of 18,7%; seeds of both cultivars submitted to heat and water stress has their physiological quality reduced and there was a reduction in the specific gravity of seeds with harvesting time delay. / Com o objetivo de verificar a qualidade fisiológica de sementes de dois cultivares de cevada, em diferentes épocas de colheita, foi instalado um experimento num campo de produção de cevada para indústria cervejeira, na localidade de Piratini/RS, no ano de 2006. As sementes analisadas foram dos cultivares MN858 e SCARLETT, as colheitas iniciaram quando as panículas estavam com a umidade em torno de 30% (maturação fisiológica) e as demais colheitas a intervalos regulares de dez dias. Para determinar a qualidade fisiológica das sementes foram realizadas as seguintes análises: germinação, primeira contagem de germinação, tetrazólio, envelhecimento acelerado, peso de mil sementes, peso hectolítrico, comprimento da parte aérea e sistema radicular, fitomassa fresca e seca da parte aérea e do sistema radicular e condutividade elétrica. O delineamento experimental utilizado foi inteiramente ao acaso com quatro repetições e as médias comparadas pelo teste de Duncan com 5% de significância. Conclui-se que os cultivares de cevada em estudo, possuem dormência na umidade em que foram colhidos; com o atraso da colheita o cultivar MN858 aumenta, intensamente, a dormência, enquanto que, no cultivar SCARLETT, a dormência tende a diminuir; sementes do cultivar MN858 apresentam melhor qualidade fisiológica quando colhidas com 22,8% de umidade, enquanto que no cultivar SCARLETT, com umidade de 18,7%; sementes de ambos cultivares submetidas ao estresse de alta temperatura e umidade tem sua qualidade fisiológica reduzida e o peso específico das sementes tende a reduzir com o atraso da colheita
64

AVALIAÇÃO DA QUALIDADE DE SEMENTES E MUDAS DE ESPÉCIES FLORESTAIS NATIVAS / NATIVE FOREST SPECIES SEEDS AND SEEDLINGS QUALITY EVALUATION

Cherobini, Edicléia Aparecida Iensen 23 March 2006 (has links)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The native forest species seeds are the responsible for the maintenance and perpetuation of those in nature, being for natural germination or by programs of seedlings formation for the forest recomposing. The use of fast tests to evaluate the seeds quality and to supply to the producer or nursery the specify information due to the sowing performance is the great importance in the process of seedlings production. The low germination or emergency percentage of plantules can be a consequence of problems as numbness of the seeds, low energy or due to the low physiologic and sanitary quality. The quality of the seeds is a sum of a series of aspects, among them the sanitary quality assumes fundamental importance. The association of pathogenic microorganisms in the seeds could influence the viability, longevity and the pathogenic transmission to the resulting plant. The present work had been evaluated four native forest species: Schizolobium parahyba (Vell.) S. F. Blake, Enterolobium contortisiliquum (Vell.) Morong, Cedrela fissilis (Vell.) and Sesbania virgata Poir, being justified by the economical and ecological importance that they present and their necessary studies, evaluating the seeds and seedlings quality of these species. The present study had been accomplished with the objective of determining the physiologic and sanitary quality of native forest species seeds, coming from Rio Grande do Sul, Santa Catarina and Paraná, through different tests. The experiments had been accomplished in the Phytosanitary Defense Laboratory and in the Forest Nursery. Germination, energy, and sanity tests had been conducted as well as seedlings evaluation starting from these seeds had been done to evaluate the potential of these ones in the good quality seedlings production. The present study had been showed that the pathogen presence as Aspergillus spp. and Penicillium spp. could cause losses in germination due to the seeds rottenness. The presence of these microorganisms is related to the collection and storage conditions in inadequate form. Fungus of Fusarium and Alternaria gender had been found in the seeds of different origins causing interference in the seedlings quality and consequently they had been reduced the establishment of the plants in the field. / As sementes de espécies florestais nativas são as responsáveis pela manutenção e perpetuação destas na natureza, seja pela germinação natural ou por programas de formação de mudas para a recomposição florestal. O uso de testes rápidos para avaliar a qualidade das sementes e fornecer ao produtor ou viveirista informações precisas quanto ao desempenho na semeadura é de grande importância no processo de produção de mudas. A qualidade das sementes é um somatório de uma série de aspectos, dentre os quais a qualidade sanitária assume importância fundamental. A associação de microorganismos patogênicos nas sementes pode influenciar na viabilidade, longevidade e na transmissão para a planta resultante. O presente estudo foi realizado com o objetivo de determinar a qualidade fisiológica e sanitária de sementes das espécies florestais nativas: Schizolobium parahyba (Vell.) S. F. Blake, Enterolobium contortisiliquum (Vell.) Morong, Cedrela fissilis (Vell.) e Sesbania virgata Poir, procedentes do Rio Grande do Sul, Santa Catarina e Paraná, através de diferentes testes. Os experimentos foram realizados no Laboratório de Fitopatologia e no Viveiro Florestal da UFSM. A avaliação da qualidade das sementes foi realizada através dos testes de germinação, vigor e sanidade. A avaliação da qualidade das mudas resultantes foi realizada através de testes em viveiro. O presente estudo mostrou que a presença de patógenos, como Aspergillus spp. e Penicillium spp., podem causar perdas na germinação devido ao apodrecimento de sementes. Fungos do gênero Fusarium e Alternaria, encontrados nas sementes das diferentes procedências, causam interferência na qualidade das mudas e, conseqüentemente, reduzem o estabelecimento das plantas no campo. Através dos testes realizados com as sementes coletadas nos diferentes Estados da Região Sul, foi possível verificar as diferenças dos níveis de vigor e a alta correlação com emergência de plantas no viveiro. Independente do Estado de origem, as sementes das diferentes espécies apresentaram variações na qualidade fisiológica e sanitária.
65

Dynamics of individual vigour and burnout in the police service

Louw, Gerrit Johannes 11 1900 (has links)
Police officers provide emergency services to the public, while being simultaneously exposed to various organisational and social stressors over which they have little or no control. The outcome of this may be that highly committed and loyal police officers become psychologically and physically burned-out. Adversely, others may accept the same conditions and situations as a challenge and live an energetic and proactive life while experiencing a positive affective state (vigour) toward their duties. Officers who are burned-out may fail to meet their goal to protect the public, but eventually may suffer. The general objective of this study was to investigate vigour and burnout as obliquely related outcomes of the stress and coping process in terms of its dynamic relationship with challenges or threats, and the mediating role of personal factors, social resources and coping resources in the police context. The research is a qualitative explication of theoretical concepts and constructs, followed by a quantitative empirical survey design. The survey led to a Structural Equation Model (SEM) fit between empirical data and the Moos (1994) hypothesised stress and coping model. Seven measuring instruments were used to collect data. Job demands, work overload and uncertainty were identified as causes of work stress originating within the work situation. Respondents indicated that family members play a role in social support, although it decreases when stress increases. The SEM procedure revealed that social support and personality has a limited and direct effect on well-being when experiencing a positive affective state (vigour), with coping strategies deleted from the experimental model. Adversely, stress has a direct effect on well-being (and eventually burnout) with no moderating effects by the hypothesised variables. The study proposes a new Police Vigour and Burnout Model (PVBM) as an alignment to the Moos (1994) model. It is recommended that vigour and burnout, as outcomes of the stress and coping process, be included in future studies as obliquely related variables in other spheres of society. An additional proposal is that stress inducing features within the police organisation should be scrutinized and critically addressed to prevent negative psychological affects. / Industrial Psychology / D.Litt. et Phil. (Industrial and Organisational Psyschology)
66

Sense of coherence, work engagement and organisational commitment within an automotive development institution

Pillay, Kogie 10 1900 (has links)
This research explores the relationship between sense of coherence, work engagement and organisational commitment in an automotive development institution in South Africa. The study was conducted through quantitative research. The study used the Orientation to Life Questionnaire (OLQ) to measure sense of coherence, the Utrecht Work Engagement Scale (UWES) to measure work engagement and the Organisational Commitment Scale (OCS) to measure organisational commitment. A biographical questionnaire was also used. The questionnaires were administered to a sample of 46 employees, 37 of whom were based in the company’s Pretoria office and nine at their Eastern Cape office. In view of the fact that the sample was small, 100 % of the population was included in the study. A theoretical relationship between the constructs was determined and an empirical study provided evidence of the degree of relationship that existed between them. The results reveal significant relationships to exist between some sub-scales, however, statistical significance could not be reached for some correlations. / Psychology / M. Admin. (Industrial and Organisational Psychology)
67

Burnout, work engagement and sense of coherence in nurses working at a central hospital in KwaZulu Natal

Maturure, Talent 03 1900 (has links)
The key objective of this study was to determine the relationship between burnout (measured by the Maslach Burnout Inventory – Human Services Survey (MBI-HSS)), work engagement (measured by the Utrecht Work Engagement Scale), and sense of coherence (measured by the Orientation of Life Questionnaire developed by Antonovsky (1987)). A quantitative study using a cross-sectional survey research design was conducted on a randomly selected sample (N = 178) of nurses at a central hospital in Kwa-Zulu Natal. A theoretical relationship was established between the variables. The empirical relationship revealed statistically significant negative relationship between burnout and work engagement. A statistically significant negative relationship was also established between burnout and SOC. The findings add valuable knowledge to industrial and organisational psychology and can be applied to promote employee and organisational wellness. / Industrial and Organisational Psychology / M. Com. (Industrial and Organisational Psychology)
68

Depressed, not depressed or unsure : prevalence and the relation to well-being across sectors in South Africa / Christa Welthagen

Welthagen, Christa January 2011 (has links)
Depression is one of the most debilitating, widespread and costly health problems worldwide and has a high prevalence in almost every society. Research suggests that depression affects an individual‟s work engagement levels, burnout levels and the occurrence of stress-related ill health symptoms. However, it is unclear whether these findings would differ among individuals who reported that they suffer from depression and receive medical treatment for it, individuals who reported that they are unsure whether they suffer from depression, and individuals who reported that they do not suffer from depression. This study is quantitative in nature and a cross-sectional design was used. The study population consisted of 15 664 participants from several sectors in South Africa. The participants also differed in terms of gender, age, race, marital status, educational level, language and the province where they reside. The sample population was thus representative of the diverse population of South Africa. The SAEHWS, a self-report instrument based on the dual-process model of work-related well-being, was used to measure all constructs. The participants were divided into three groups, i.e. individuals who reported that they suffer from depression and are currently receiving medical treatment for depression, individuals who reported that they are uncertain whether they suffer from depression, and individuals who reported that they do not suffer from depression. Frequencies were used to determine the prevalence of depression in the three different groups and MANOVA (multivariate analysis of variance) was used to determine the significance of differences between the levels of work engagement, burnout and stress-related ill health symptoms of the three different groups (individuals who reported that they suffer from depression, individuals who reported that they are uncertain whether they suffer from depression, and those who reported that they do not suffer from depression). The results showed that 18,3% of the population reported that they suffer from depression and receive medical treatment for depression, 16,7% of the population reported that they are unsure whether they suffer from depression and 65% reported that they do not suffer from depression. Furthermore, it was found that depression significantly influences work engagement levels negatively and that it significantly influences burnout levels and the occurrence of stress-related ill health symptoms positively. This study will make organisations aware of the effect of depression on an individual‟s well-being and of the fact that depression is a factor to be reckoned with. Employers should consider ways to assist employees who suffer from depression and should learn how to act preventatively to decrease any further occurrence. / Thesis (M.Com. (Industrial Psychology))--North-West University, Potchefstroom Campus, 2011
69

Déterminisme génétique des réponses au déficit hydrique de la transpiration et de la croissance, induites par le porte-greffe, chez la vigne : approche intégrée de génétique quantitative et d'écophysiologie / Genetic determinism of transpiration and growth responses to water deficit induced by grapewine rootstock : integrated analysis with ecophysiology and quantitative genetics

Marguerit, Elisa 10 December 2010 (has links)
Dans le contexte de raréfaction de la ressource en eau, il est nécessaire de prendre en compte le caractère de tolérance à la sécheresse dans les programmes d’amélioration variétale, en particulier pour les porte-greffes de vigne. L’objectif de cette thèse est d’analyser, à l’échelle de la plante entière, le déterminisme génétique des effets du porte-greffe sur les réponses de la tranpiration et de la croissance, au niveau de la partie aérienne, en conditions de déficit hydrique édaphique. L’étude de ces caractères complexes, soumis à une forte interaction génotype × environnement, a été conduite à partir d’une approche de génétique quantitative où ces interactions ont été intégrées par deux approches : l’utilisation des paramètres de courbes de réponses comme caractère quantitatif et la mise en oeuvre d’une analyse QTL pluriannuelle. Une population de type F1, issu du croisement Vitis vinifera Cabernet Sauvignon × Vitis riparia Gloire de Montpellier, constituée de 138 individus, a été cartographiée génétiquement avec des marqueurs microsatellites. Cette descendance a été ensuite phénotypée en position de porte-greffe, avec un greffon unique. A partir de cet outil, des QTL ont été recherchés et identifiés pour la transpiration, l’efficience d’utilisation de l’eau et la plasticité de la transpiration induite par le porte-greffe, ainsi que pour plusieurs paramètres de la croissance et de l’allocation de la biomasse au sein de la plante entière. La plasticité de la transpiration réponse à l’état hydrique du substrat est déterminée génétiquement par des régions distinctes des autres caractères descriptifs de la consommation en eau. La colocalisation de gènes candidats dans les intervalles de confiance des QTL, impliqués dans la signalisation chimique (ABA) ou hydraulique (aquaporines) permet de formuler des hypothèses sur la signalisation porte-greffe/ greffon en condition de déficit hydrique. Des régions spécifiques du génome paraissent contrôler la croissance et la vigueur conférée par le porte-greffe en conditions de déficit hydrique. Ces régions sont également indépendantes de celles contrôlant la transpiration ou l’efficience d’utilisation de l’eau. Ce résultat permet d’envisager un travail de sélection pour ces deux catégories de caractères de manière indépendante / In the water scarcity context with the global climate change, drought tolerance must be taken into account in crop genetic improvement program, particularly for grapevine rootstocks. The objective of this thesis was to analyse at the whole plant level, the genetic determinism of rootstock effect on the transpiration and growth of the scion, under edaphic water deficit conditions. The study of these complex traits, submitted to a strong genotype × environment interaction, was performed with a quantitative genetic approach. Genotype × environment interactions were integrated with two methods: first, using response curve to an environmental variable for detecting QTL, and secondly, to combine data in a multi-environment QTL analysis. The pedigree population consisted of 138 F1 individuals derived from the interspecific cross of Vitis vinifera Cabernet Sauvignon × Vitis riparia Gloire de Montpellier. This family was mapped with single sequence repeats (SSR) markers. This population was assessed as rootstock, so every genotype was grafted with the same scion. Then, QTL were detected for transpiration, water use efficiency and transpiration plasticity induced by rootstock, and for growth and biomass allocation inside the whole plant. Transpiration plasticity was represented as a function of substrate water status and was genetically determined with distinct genome regions from the other traits related to water consumption. Candidate genes involved in hormonal (ABA) or hydraulic (aquaporins) signaling between rootstock and scion, under water deficit conditions, were localized in the QTL confidence interval. Some specific genome regions were involved in growth and confered vigour genetic determinism under water deficit conditions. These regions were also different from those identified for transpiration or water use efficiency. This result allows a further selection process for these two traits groups independently.
70

Determining seed vigour in selected Brassica species

Leeks, C. R. F. January 2006 (has links)
Variables for the accelerated ageing (AA) test, methods for reducing fungal contamination during the AA test, using the conductivity test as a vigour test, the effect of seed size on seed vigour and the relationship between laboratory test results and field perfonnance in selected Brassica spp were investigated. In the first experiment, three seed lots of turnip rape hybrid (B. rapa x campestris), turnip (B. campestris) and forage rape (B. napus); and seven seed lots of Asian rape (B. napus), six seed lots of Asian kale (B. oleraceae var. alboglabra L.) and five seed lots of choisum (B. rapa var. pekinensis) with germinations above 90% were aged at two different temperatures (41 and 42°C ± 0.3°C) and three ageing times (24, 48 and 72 ± 15 minutes). The second experiment was divided into three sections. In the first, the same seed lots and species were aged at one temperature (41°C) and time (72 h), but either 40 ml of saturated salts; KCl (83%RH), NaCl (76%RH), NaBr (55%RH); or distilled water (96%RH) were used as the ageing solutions. In the second, one turnip rape hyprid seed lot was aged at three temperatures (41, 42 and 45°C) and two times (72 and 96h), again using the three saturated salts and distilled water as ageing solutions. In the third, three turnip rape hybrid seed lots and three Asian kale seed lots were surface sterilised (1 % sodium hypochlorite) prior to ageing at one temperature (41°C) and time (72 h). In the third experiment, the same species and seed lots used in experiment one at their original seed moisture content (SMC) were tested for conductivity after soaking in deionised water for 4, 8, 12, 16, 20 and 24 h. They were then re-tested after the SMC had been adjusted to 8.5%. In the fourth experiment, three seed lots of forage rape and three seed lots of Asian kale were graded into three seed size categories; large (retained on a 2.0 mm screen), medium (retained on a 1.7 mm screen) and small (passed through a 1.7 mm screen). Graded seeds were then tested for standard germination, AA (41°C/48 h) and conductivity (measured at 16 and 24 h). In the final experiment, the relationships between laboratory tests for the six species (each consisting of three seed lots), field emergence from three sowings, and cold room emergence were evaluated. Both time and temperature influenced post-AA germination. Increasing the ageing period from 48 to 72 hours at 41°C, and 24 to 48 hours at 42°C resulted in decreased mean germination percentage for all species but not always clear separation of seed lots. While there were sometimes few differences between ageing at 41°C and 42°C, the former is preferred because it is already the temperature used for other species. For Asian rape, choisum and turnip, the previously recommended testing conditions of 41°C/72 h provided good seed lot separation, but for Asian kale and turnip rape hybrid, AA testing at 41°C/48 h provided better results. Seed moisture content after ageing ranged from 29-37% depending on species. Fungal growth on seeds during the ageing period appeared to reduce post-ageing germination in some seed lots . Substituting saturated salts for distilled water did not stress seed lots in the AA test, due to the lowered RH%, the exception being seed lots 1210 and 1296. For forage and Asian species, seed lot germination mostly remained above 90% when aged for 72 h at lowered RH%. Increasing the ageing duration from 72 to 96 hours resulted in some decreases in post-AA germination but no clear separation of seed lots. Surface sterilising the seeds prior to the AA test resulted in a lower incidence of contaminant fungi which was associated with a lower percentage of abnormal seedlings. The conductivity test was mostly able to identify vigour differences among forage and Asian vegetable brassica seed lots. Differences in conductivity readings were observed among seed lots in all species. Increasing the period of imbibition resulted in increased conductivity from most seed lots but radicle emergence occurred after 16-20 h of imbibition. Variation was observed in the time to reach 95% maximum of the imbibition curve for most species. Conductivity readings at 16 h would avoid possible influences of radicle emergence on results. Adjusting the SMC to 8.5% resulted in reduced variation in conductivity among replicates of seed lots, due to a reduction in imbibition damage. Seed size had a significant effect on both post-AA germination and conductivity results. In forage rape, large size seeds had higher post-AA germination cf. medium cf. small size seeds. In Asian kale, large size seeds had higher post-AA germination compared with small size seeds. For both forage rape and Asian kale, large size seeds had lower conductivity readings cf. small size seeds. The correlation analyses demonstrated significant relationships between AA testing and field emergence parameters (percentage emergence, emergence index and emergence rate). Significant relationships were also observed between conductivity testing and these field emergence parameters. Based on the correlation analysis, AA testing at 41°C/48 hand/or 42°C/48 h could be recommended to be used as an AA test for turnip and Asian rape; and 41°C/48 hand/or 41°C/72 h for Asian kale and choisum. Based on the correlation analysis, conductivity testing at 16 h can be used to predict the field emergence potential of forage and Asian vegetable seed lots. Vigour tests were consistently able to provide better indicators of field perfonnance than the standard germination test, although these relationships did vary with the different field sowings.

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