Made available in DSpace on 2014-08-20T13:44:36Z (GMT). No. of bitstreams: 1 tese_alexandra_alves_cantos.pdf: 1317574 bytes, checksum: 62dbb23b4f8352e1b319ab6739d8c5a2 (MD5) Previous issue date: 2013-12-17 / This study aimed to determine the conditions for seed germination test and evaluate the best substrate for the production of seedlings of species of Quillaja brasiliensis (A.St. - Hil & Tul) Mart. The seeds of Q. brasiliensis were sown four replications of 25 seeds in paper substrates and sand as recommended by the RAS. Sowing was between paper, on paper, between sand and on sand subjected to a constant temperature of 20 º C. First count of germination (PCG) was analyzed, and germination speed index (GSI), mean germination time (MGT) and determination of moisture content of the batch worked (U ).Two arrays were used for seed collection, located on the edge of the riparian zone of the Arroio Lavras do Sul, RS. For the assessment of germination in different substrates for the production of seedlings via seed , the following materials and compositions : T1 : Vermiculite , T2 : Coconut Fiber , T3 : Commercial Substrate , T4 : 50% carbonized rice husk ( CAC ) + 50 % vermiculite , T5 : 50 % CCS and 50 % coconut fiber. The tests were performed in trays of polystyrene, four replicates of 36 seeds were used. Each seed was covered with a layer of 1 cm substrate for testing for germination and seedling performance. The experiment was conducted for 120 days, during this period, the trays remained in the laboratory, receiving natural light (indirect) and subject to fluctuations in temperature and RH (%) of the environment . The following variables were analyzed to compare the performance of substrates: shoot height, ratio of height of shoot and root, length of taproot, number of lateral roots , number of leaves. In the assessment of seedling competitions we sought to determine the influence of the number of seeds per cell in 72 cells polystyrene tray with vermiculite + carbonized rice husk ( CAC) in 50:50 ( % ) in the emergence of seedlings. Seed of the same batch of those used in the performance tests as a function of substrate were used. Seeds were distributed in four replicates of 11 cells, distributed by treatments: T1 : one seed per cell, T2 : two seeds per cell, T3 : three seeds per cell and T4 : four seeds per cell. The experiment was conducted for 60 days and assessed according to the seedling emergence or not and depending on the number of cells in which seedlings had emerged. The moisture content was determined by the use of two replicates 1g of intact seeds. It was concluded that for the test laboratory germination the seeds are sown in the paper substrate and methodologies on paper and paper roll. The first count of germination should be performed on the sixth day after sowing and the test ended on the 14th day after sowing. The indicated photoperiod is 16 hours of light at a constant temperature of 20 ° C. To assess the production of seedlings it is concluded that expanded vermiculite is a suitable substrate. In the production of seedlings is recommended to use the trays three seeds per cell and subsequently perform thinning with removal of the less vigorous seedlings. / Este trabalho teve como objetivo determinar as condições para condução do teste de germinação de sementes e avaliar o melhor substrato para a produção de mudas de Quillaja brasiliensis. A semeadura foi realizada em quatro repetições de 25 sementes, nos substratos papel e areia, nas metodologias entre papel; sobre papel; entre areia e sobre areia, submetidas à temperatura constante de 20ºC. Foi analisados primeira contagem da germinação (PCG); índice de velocidade de germinação (IVG); tempo médio de germinação (TMG) e o grau de umidade do lote (U). Na germinação em diferentes substratos para a produção de mudas via sementes, foram empregados os seguintes materiais e composições: T1: Vermiculita; T2: Fibra de coco; T3: Substrato comercial; T4: 50% de casca de arroz carbonizada (CAC) + 50% de vermiculita; T5: 50% de CAC e 50% de fibra de coco. Os testes foram realizados em bandejas de poliestileno, utilizando quatro repetições de 36 sementes. O experimento foi conduzido durante 120 dias e as bandejas permaneceram no laboratório, recebendo luz natural e sujeitas às flutuações da temperatura e UR (%) do ambiente. Para comparar o desempenho dos substratos, foram analisados: altura da parte aérea; razão entre altura da parte aérea e raiz; comprimento de raiz principal; número de raízes laterais e número de folhas. Na avaliação de competição entre plântulas determinou-se a influência do número de sementes por célula em bandeja, com o substrato vermiculita + casca de arroz carbonizada (CAC), na proporção 50:50 (%), na emergência de plântulas. As sementes foram distribuídas em quatro repetições de 11 células, distribuídos pelos tratamentos: T1: uma semente por célula; T2: duas sementes por célula; T3: três sementes por célula e T4: quatro sementes por célula. O experimento, conduzido por 60 dias, foi avaliado pela emergência ou não das plântulas e em função do número de células nas quais havia plântulas emergidas. O grau de umidade foi determinado em duas repetições de 1g de sementes intactas. Concluiu-se que, para o teste de germinação, as sementes sejam semeadas em substrato papel, nas metodologias sobre papel e rolo de papel. A primeira contagem da germinação deve ser realizada no sexto dia e o teste encerrado no 14º dia após semeadura. O fotoperíodo indicado é 16 horas de luz, em temperatura constante de 20ºC. Para a avaliação da produção de mudas, a vermiculita expandida é o substrato adequado. Na produção de mudas é recomendável utilizar nas bandejas três sementes por célula e, posteriormente, realizar o raleio, com remoção das plântulas menos vigorosas.

Fruit and vegetable residue (FVR) can be used for the production of organic compost, which when mineralized may provide nutrients to fruit trees, such as the Pecan (Carya illinoinensis (Wang) K.). The objective of the study was to produce an organic compound from the mixture of different ratios of fruit and vegetable residue (FVR), rice husk (RH) and poultry manure (PM) that meets the minimum quality requirements demanded by legislation, as well as to evaluate the N mineralization of the organic compound used in the composition of the substrates to be used in the production of Pecan (Carya illinoinensis (Wang) K.) rootstock cultivar. This study was divided into two studies: Study 1 (Composition and mineralization of organic compounds derived from the composting of fruit and vegetable residues) and Study 2 (Growth and nutritional status of Pecan rootstock cultivar subjected to the application of an organic compound-based substrate). In Study 1, four treatments (piles) were assembled with different ratios of mixtures of FVR:RH:PM (v:v): 2:1:0, 1:1:1, 1.5:1:0 and 1.2:1:0. The treatments were submitted to the composting process for a period of 95 days. Four organic compounds were obtained (C1, C2, C3 and C4) and analyzed using the following parameters: TOC Nt, C/N CEC/C, EC, pH, moisture content, N-NH4+, N-NO3-, and contents of P, K, Ca, Mg, Cu, S, Mn and Zn. The second stage of this study was to perform the N mineralization test of the organic compound (C2) produced in the first stage of the study, used together with agricultural peat (AP) and carbonized rice husk (CRH) in the composition of the following treatments: 40%AP+60%CRH (control), 20%AP+80%C2, 30%AP+70%C2, 40%AP+60%C2, 50%AP+50%C2, 60%AP+40%C2, 70%AP+30%C2 and 80%AP+20%C2. The contents of N-NH4+, N-NO3-, mineral N and mineralized N were analyzed in relation to the total added at each time (0, 7, 14, 28, 56 and 112 days). In Study 2, the 40%AP+60% CRH (control), 20%AP+80%C2, 30%AP+70%C2, 40%AP+60%C2, 50%AP+50%C2, 60%AP+40%C2, 70%AP+30%C2 and 80%AP+20%C2 treatments were analyzed in relation to the development and nutritional status of Pecan rootstock cultivar in the period of 112 days. In Study 1, the constant additions of fruit and vegetable residues showed no significant difference in the temperature pattern developed in the compost piles. The composting of fruit and vegetable residues and rice husk requires an external source of nutrients to produce an organic compound within the minimum standards of quality required by organic fertilizer legislation. The compost (C2) exhibited excellent performance and the results were within the standards required by legislation in the following maturation and quality parameters: C/N ratio, TOC, N, P, K, Ca, Fe, Mn, CEC/C, pH, and moisture%. The use of organic compound in substrate composition favored N mineralization in comparison to the control treatment, especially the 40%AP+60%C2 mixture, which exhibited the highest NH4+ value at all the evaluated times, and the 60%AP+40%C2 mixture with the highest NO3-, mineral N and mineralized N at 28 days after incubation, as well as the highest N mineralization during the evaluation period. In Study 2, rootstocks grown in the 80%AP+20%C2 and 60%AP+40%C2 treatments exhibited greater accumulation of dry shoot mass (DSM). The 50%AP+50%C2, 40%AP+60%C2 and 30%AP+70%C2 treatments showed a greater increase in height and in the accumulation of total dry matter (TDM). The 40%AP+60%C2 treatment promoted the highest accumulation of dry root mass (DRM) and Dickson quality index (DQI) in the Pecan rootstock cultivar. The doses of organic compound (C2) did not affect the concentration of nutrients in the leaves of pecan, except N, which exhibited a lower concentration in the leaves in all the treatments. Thus, the organic compound produced from residues of fruits and vegetables, rice husk and poultry manure is efficient in the production of pecan rootstock cultivar. / Resíduos de frutas e hortaliças (RFH) podem ser utilizados para a produção de composto orgânico que quando mineralizado pode disponibilizar nutrientes às plantas frutíferas como a Nogueira-Pecã (Carya illinoinensis (Wang) K.). O objetivo do estudo foi produzir um composto orgânico a partir da mistura de diferentes proporções de resíduo de frutas e hortaliças (RFH), casca de arroz (CA) e dejeto de aves (DA), que atenda aos requisitos mínimos de qualidade exigidos pela legislação de fertilizantes orgânicos, avaliar a mineralização de N do composto orgânico utilizado na composição de substratos para ser utilizado na produção de cultivar de porta-enxerto de Nogueira-Pecã (Carya illinoinensis (Wang) K). O presente trabalho foi dividido em dois estudos: Estudo 1(Composição e mineralização de compostos orgânicos derivados da compostagem de resíduos de frutas e hortaliças) e Estudo 2 (Crescimento e estado nutricional de cultivar de porta-enxerto de Nogueira-Pecã submetido a aplicação de substrato à base de composto orgânico). No Estudo 1, foram montados quatro tratamentos (pilhas), com diferentes proporções de misturas de RFH:CA:DA (v:v): 2:1:0, 1:1:1, 1,5:1:0 e 1,2:1:0. Os tratamentos foram submetidos ao processo de compostagem por um período de 95 dias. Foram obtidos 4 compostos orgânicos (C1, C2, C3 e C4), que foram analisados nos seguintes parâmetros: COT, Nt, C/N, CTC/C, CE, pH, teor de umidade, N-NH4+, N-NO3-, teor de P, K, Ca, Mg, Cu, S, Mn e Zn. A segunda etapa deste estudo foi a realização de teste de mineralização de N do composto orgânico (C2), produzido na primeira etapa do estudo, utilizado juntamente com a turfa agrícola (TA) e casca de arroz carbonizada (CC) na composição dos seguintes tratamentos: 40%TA+60%CC (controle), 20%TA+80%C2, 30%TA+70%C2, 40%TA+60%C2, 50%TA+50%C2, 60%TA+ 40%C2, 70%TA+30%C2 e 80%TA+20%C2. Foram analisados os teores de N-NH4+, N-NO3-, N mineral e N mineralizado em relação ao total adicionado nos tempos (0, 7, 14, 28, 56 e 112 dias). No Estudo 2, foram avaliados os tratamentos 40%TA+60%CC (controle), 20%TA+80%C2, 30%TA+70%C2, 40%TA+60%C2, 50%TA+50%C2, 60%TA+ 40%C2, 70%TA+30%C2 e 80%TA+20%C2 no desenvolvimento e estado nutricional de cultivar de porta-enxerto de Nogueira-Pecã no período de 112 dias. No Estudo 1, as constantes adições de resíduos de frutas e hortaliças não demonstraram diferença significativa no padrão de temperatura desenvolvido nas pilhas de compostagem. A compostagem de resíduos de frutas e hortaliças e casca de arroz, necessita de uma fonte externa de nutrientes para produzir um composto orgânico dentro dos padrões mínimos de qualidade exigidos pela legislação de fertilizantes orgânicos. O composto (C2) apresentou desempenho superior com resultados conforme exige a legislação nos seguintes parâmetros de maturação e qualidade: relação C/N, COT, teores de N, P, K, Ca, Fe, Mn, CTC/C, pH e umidade%. A utilização de composto orgânico na composição do substrato, favoreceu a mineralização de N em relação ao tratamento controle, com destaque para a mistura 40%TA+60%C2 que apresentou a maior valor de NH4+ em todas as datas avaliadas, 60%TA+40%C2 com maior valor de NO3- , N mineral e N mineralizado aos 28 dias após a incubação, assim como também apresentou a maior mineralização do N no período avaliado. No Estudo 2, os porta-enxertos cultivados nos tratamentos 80%TA+20%C2 e 60%TA+40%C2 apresentaram maior acúmulo de massa seca da parte aérea (MSPA). Os tratamentos 50%TA+50%C2, 40%TA+60%C2 e 30%TA+70%C2, apresentaram maior incremento em altura e acúmulo de massa seca total (MST). O tratamento 40%TA+60%C2 favoreceu o maior acúmulo de massa seca de raiz (MSR) e o índice de qualidade de Dickson (IQD) em cultivar de porta-enxerto de Nogueira-Pecã. As doses de composto orgânico (C2) não afetaram a concentração de nutrientes nas folhas de nogueira-pecã, exceto o N que apresentou menor concentração nas folhas em todos os tratamentos avaliados. Assim, o composto orgânico produzido a partir de resíduos de frutas e hortaliças, casca de arroz e dejeto de aves é eficiente na produção de cultivar de porta-enxerto de nogueira-pecã.

Abstract Mutualism is often conditional and the associations vary from antagonism to mutualism along environmental conditions and genotypes of interacting species. I studied antagonism-mutualism continuum hypothesis of symbiosis experimentally using two different Epichloë/Neotyphodium endophytes and their host grasses, agricultural meadow fescues and natural fine fescue, as study systems. These systemic fungal endophytes live asymptomatically within aerial tissues of grasses, and are vertically transmitted to the next grass generation via seeds. Thus, asexual endophyte strains are dependent on the growth, survival and reproduction of their hosts. Epichloë/Neotyphodium endophytes are considered plant mutualists, because they improve the resistance of the host against various stresses, e.g. herbivores. In addition to experimental approach, I examined prevalence and genetic structure of Epichloë festucae in natural grass populations. Finally, current knowledge concerning grass endophytes was reviewed and the effects of variable environment and genetic background on the ecology and the evolution of grass-endophyte symbiosis were discussed. The endophyte improved the performance of the agronomic meadow fescues, but the beneficial effects were dependent on the grass cultivar and the growth environment. The endophyte-infected (E+) meadow fescues were more susceptible to the pathogenic snow molds and they suffered increased winter damage compared to the endophyte-free (E-) plants. Many natural Festuca rubra and F. ovina populations were either endophyte-free or had low infection frequency. The highest infection frequencies were found in subarctic areas where the infection incidence differed between habitats. Twenty out of the 25 E. festucae genotypes detected were carrying multiple alleles in microsatellite loci indicating multiple infections or vegetative hybridization of the fungus. A dominant genotype (63.5% of all isolates) occurred in all populations suggesting that this fungus is mainly asexual. E+ F. ovina seedlings performed worse than endophyte-free E- seedlings. In F. rubra, the river bank originated E+ seedlings allocated fewer, but longer and heavier tillers than the other seedlings indicating possible improved performance of the endophyte infected grasses in harsh river bank conditions. In short, I detected both positive and negative effects of endophyte infection on grasses varying along species, environment and genotypic background of study subjects. The results support the antagonism-mutualism continuum hypothesis.

The process of environmental degradation that has been occurred in the lower region of Sao Francisco s river is reducing the permanent preservation areas. The artificial regeneration is a method of riparian restoration widely used to reconstitute the native vegetation in degraded areas. For the reasons set was a work of restoration in an area of riparian forest in Santana do São Francisco s county Sergipe, with the objective of proposing models to restore the natural balance of the environment. The studied area after tested was monitored for 60 months, using the experimental design in randomized blocks in three models restoration the riparian forest (seedlings growth of forest species in spacing 3x1,5m and 3x3m and direct seeding in spacing 3x1,5m) and twelve native forest species. There were evaluated seedling emergence, surviving and development of species tested (height, base diameter e the relative growth rate). Was also performed to evaluated phenological aspects of species tested and identified the presence of colonizing species in the studied area. The results after 60 months old of the implanted species indicated a higher percentage of surviving of species in the model with growth in spacing 3x1,5m (62,2%). It was observed that the spacement used not able to influence the development of species. To TCR (relative growth rate) was identified as the pioneer species Schinus terebinthifolius (Raddi.) had the highest rates of growth in height in three models implanted. With respect to the diameter base was observed that the species that showed the highest growth rates were Vitex polygama (Cham.), Schinus terebinthifolius (Raddi.) e Cassia grandis (L.f). Considering the phenological aspects were observed that five species (40%) showed flowering and fruiting during the 60 months of evaluation. The species studied showed up in the potential restoration of riparian forests and may be the recommended direct seeding method to reduce the costs of deployment in the lower region of Sao Francisco s river. / O processo de degradação ambiental que vem ocorrendo na região do Baixo Rio São Francisco vem reduzindo as áreas de preservação permanente. A regeneração artificial é um método de restauração ciliar muito utilizado para recompor a vegetação nativa em áreas degradadas. Pelos motivos apresentados foi realizado um trabalho de restauração em uma área de mata ciliar no município de Santana do São Francisco SE, com o objetivo de propor modelos de restabelecimento do equilíbrio natural do ambiente. A área de estudo, após implantada foi monitorada por 60 meses, sendo utilizado o delineamento experimental em blocos casualizados em três modelos de restauração da mata ciliar (plantio de mudas de espécies florestais em espaçamentos 3x1,5m e 3x3m e semeadura direta em espaçamento 3x1,5m) e doze espécies florestais nativas. Foram feitas avaliações de emergência de plântulas, sobrevivência e desenvolvimento das espécies implantadas (altura, diâmetro do colo e taxa de crescimento relativo). Também foi realizada a avaliação dos aspectos fenológicos das espécies implantadas e identificada a presença de espécies colonizadoras na área de estudo. Os resultados obtidos após 60 meses de idade das espécies implantadas indicaram um maior percentual de sobrevivência no modelo com plantio de mudas no espaçamento 3x1,5m (62,2%). Observou-se que os espaçamentos utilizados não exerceram influência no desenvolvimento das espécies. Para a TCR (taxa de crescimento relativo) foi identificado que a espécie pioneira Schinus terebinthifolius (Raddi.) apresentou as maiores taxas de crescimento em altura nos três modelos implantados. Com relação ao diâmetro do colo observou-se que as espécies que apresentaram as maiores taxas de crescimento foram Vitex polygama (Cham.), Schinus terebinthifolius (Raddi.) e Cassia grandis (L.f). Considerando-se os aspectos fenológicos foram observados que cinco espécies (40%) apresentaram floração e frutificação durante os 60 meses de avaliação. As espécies estudadas apresentaram-se potenciais no processo de restauração de matas ciliares, podendo ser recomendado o método de semeadura direta para reduzir os custos da implantação na Região do Baixo Rio São Francisco.

The landscapes of the Great Basin and Mojave Deserts are changing due to plant invasion. Highly flammable invasive grasses increase the size and frequency of fire causing a cascade of effects through the plant and animal communities. One of the most influential animal groups in desert systems is small mammals. We sought to learn how small mammals are impacted by fire and how their influence on the plant community differs between burned and unburned habitat. Small mammals did not have higher rates of mortality as a direct result of a controlled burn. In the Great Basin, there were short-term reductions in abundance, richness, and diversity of the small mammal community in burned plots. In the Mojave, species richness and diversity increased in burned plots shortly after fire and no abundance differences were detected. These results correspond with our prediction based on the dominant small mammal species at each site. Small mammals are primarily granivores; however, they also have strong impacts on the plant community via folivory. We tested for small mammal impacts on seedling survival in burned and unburned habitat. Small mammal access, burned vs. unburned habitat, and plant species were all important determinants of survival. Small mammals greatly reduced survival at both sites in burned and unburned habitat and often had a stronger impact in unburned than burned plots. Accounting for small mammal folivory may be a crucial step in successful post-fire rehabilitation. Finally, we used seed trays to test how small mammals influence the persistence of seed on the landscape. Small mammals reduced persistence of an invasive and native plant species in the Great Basin in 2012, yet a year later when small mammal abundance was reduced, no small mammal effect was observed. In the Mojave, persistence was reduced for the majority of species both years of the study. Small mammals did not appear to avoid seed of invasive plant species as we had predicted and may be important consumers reducing the reproductive potential of these invaders. If small mammals do prefer non-native seedlings over natives and are also consuming non-native seed, they may be greatly reducing the presence of non-natives both on the unburned landscape as well as after fire. Non-native consumption by small mammals could aid in the biotic resistance of these desert ecosystems. This research further enforces the important role that small mammals play as consumers, dispersers, and regulators of the plant community.

This thesis includes two studies. The first study examined changes in soil characteristics as a result of prolonged conifer dominance in successional aspen-conifer forests. Changing disturbance patterns in aspen-conifer forests appear to be altering successional dynamics that favors conifer expansion in aspen forests. The primary objective of this paper was to identify how increasing conifer dominance that develops in later successional stages alters forest soil characteristics. Soil measurements were collected along a stand composition gradient: aspen dominated, aspen-conifer mix, conifer dominated and open meadow, which includes the range of conditions that exists through the stages of secondary succession in aspen-conifer forests. Soil chemistry, moisture content, respiration, and temperature were measured. There was a consistent trend in which aspen stands demonstrated higher mean soil nutrient concentrations than adjacent meadows, mixed or conifer stands. Soil moisture was significantly higher in aspen stands and meadows in early summer. Soil respiration was significantly higher in aspen stands than conifer stands or meadows throughout the summer. The results indicate that soil resource availability and respiration peak within aspen dominated stands that are present during early succession and then decrease as conifer abundance increases along our stand composition gradient, representative of stand characteristics present in mid to late successional stages. Emerging evidence from other studies suggest that these observed changes in soil characteristics with increasing conifer dominance may have negative feedbacks on aspen growth and vigor. The second study examined the facilitation effect between aspen and subalpine fir establishment. In subalpine forests, conifer species are often found intermixed with broadleaf species. However, few if any studies have explored the existence and influence of facilitation between broadleaf tree species and conifers. We have observed the general establishment of subalpine fir seedlings at the base of aspen trees in a subalpine forest, indicating that a facilitative relationship may exist. To explore the potential facilitative relationship during secondary succession in subalpine forests, subalpine fir seeds were planted across a stand composition gradient (aspen dominated → mixed → conifer dominated stands) at six study sites in the Fishlake National Forest. Seeds were placed during the fall of 2010, at distances of 0 cm and 25 cm in each cardinal direction at the base of mature aspen and subalpine fir trees in each of the three stand types. Seeds were also planted within stand interspaces and in adjacent meadows. Seedling emergence was recorded at the beginning of the summer of 2011 and seedling mortality was recorded in October 2011. Soil moisture content was measured at the position that seeds were placed during the summers of 2009 and 2011. Aspen dominated stands had subalpine fir germination that was on average 11 times greater than mixed or conifer dominated stands. Germination was 2.3 fold greater at the base of aspen trees than fir trees and two fold greater at the base of aspen trees than interspaces. Seedling mortality was lower in aspen stands but was not significantly influenced by position relative to mature trees. Soil moisture was highest in aspen dominated stands, with better soil moisture conditions at the base of aspen trees and in interspaces compared to the base of fir trees. Few if any studies regarding conifer facilitation have provided evidence for facilitation at the germination life stage, rather they focus on seedling survival. However, our study illustrates a strong facilitative interaction in which both aspen dominated stands and aspen trees increase the likelihood of subalpine fir seedling establishment by drastically increasing rates of subalpine fir germination. Because of aspen's primary role in initiating secondary succession through post-disturbance sucker regeneration, and the subsequent dependence of conifers on aspen for establishment, aspen mortality via competition with conifers under longer fire cycles, droughts, or intensive ungulate browsing may result in a loss of aspen-conifer forest communities in some locales.

No description available.

No description available.

El virus de la tristeza de los cítricos (CTV) ha causado millonarias pérdidas a la citricultura a nivel mundial. En Chile, la situación real era desconocida aunque se había reportado su presencia en limoneros Meyer, los que fueron erradicados. El objetivo de esta tesis fue analizar la situación actual de CTV en Chile, realizar una amplia prospección y estimar su incidencia, estudiar su epidemiología y realizar una caracterización biológica, serológica y molecular de 100 aislados chilenos de CTV representativos. Se realizó un estudio epidemiológico en seis parcelas experimentales y dos ensayos de trasnsmisión con 10 aislados representativos. CTV fue detectado en casi todas las zonas citrícolas de Chile, con una incidencia media del 0,38%. En el oasis de Pica (I Región), se observaron acanaladuras en la madera en árboles de pomelo y lima mejicana. Se detectan todas las especies vectoras de CTV, a excepción de Toxoptera citricida. En la zona central de Chile se determina la presencia mayoritaria de aislados atenuados (MCA13 negativos). En la I Región (oasis de Pica y Malilla) la presencia de aislados agresivos, siendo todos MCA13 positivos y características moleculares asociadas al tipo VT. Se demostró un aumento en la incidencia de CTV en las parcelas experimentales, salvo en un huerto de limonero. En ensayos de transmisión sólo un aislado de CTV fue transmitido con una eficiencia baja de transmisión. En base a los resultados obtenidos se dan recomencaciones para la citricultura chilena. / Besoain Canales, JA. (2008). Incidencia, caracterización y epidemiología del virus de la tristeza de los cítricos en Chile [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/2009

京都大学 / 新制・課程博士 / 博士(理学) / 甲第25145号 / 理博第5052号 / 新制||理||1720(附属図書館) / 京都大学大学院理学研究科生物科学専攻 / (主査)講師 嶋田 知生, 教授 松下 智直, 教授 鹿内 利治 / 学位規則第4条第1項該当 / Doctor of Agricultural Science / Kyoto University / DFAM