Broccoli is a vegetable crop of increasing importance in Australia, particularly in south-east Queensland and farmers need to maintain a regular supply of good quality broccoli to meet the expanding market. However, harvest maturity date, head yield and quality are all affected by climatic variations during the production cycle, particularly low temperature episodes. There are also interactions between genotype and climatic variability. A predictive model of ontogeny, incorporating climatic data including frost risk, would enable farmers to predict harvest maturity date and select appropriate cultivar - sowing date combinations. The first stage of this research was to define floral initiation, which is fundamental to predicting ontogeny. Scanning electron micrographs of the apical meristem were made for the transition from the vegetative to advanced reproductive stage. During the early vegetative stage (stage 1), the apical meristem was a small, pointed shoot tip surrounded by leaf primordia. The transitional stage (stage 2) was marked by a widening and flattening to form a dome-shaped apical meristem. In the floral initiation stage (stage 3), the first-order floral primordia were observed in the axils of the developing bracts. Under field conditions, the shoot apex has an average diameter of 500 micro m at floral initiation and floral primordia can be observed under a light microscope. Sub-zero temperatures can result in freezing injury and thereby reduce head yield and quality. In order to predict the effects of frosts, it is desirable to know the stages of development at which plants are most susceptible. Therefore, the effects of sub-zero temperatures on leaf and shoot mortality, head yield and quality were determined after exposure of plants to a range of temperatures for short periods, at different stages of development (vegetative, floral initiation and buttoning). Plants in pots and in the field were subjected to sub-zero temperature regimes from -1 C to -19 C. Extracellular ice formation was achieved by reducing temperatures slowly, at a rate of -2 C per hour. The floral initiation stage was most sensitive to freezing injury, as yields were significantly reduced at -1 C and -3 C, and shoot apices were killed at -5 C. There was no significant yield reduction when the inflorescence buttoning stage was subjected to -1 C and -3 C. Although shoot apices at buttoning survived the -5 C treatment, very poor quality heads of uneven bud size were produced as a result of arrested development. The lethal temperature for pot-grown broccoli was between -3 C and -5 C, whereas the lethal temperature for field-grown broccoli was between -7 C and -9 C. The difference was presumably due to variation in cold acclimation. Freezing injury can reduce broccoli head yield and quality, and retard plant growth. Crop development models based only on simple thermal time without restrictions will not predict yield or maturity if broccoli crops are frost-damaged. Field studies were conducted to develop procedures for predicting ontogeny, yield and quality. Three cultivars, (Fiesta, Greenbelt and Marathon) were sown on eight dates from 11 March to 22 May 1997, and grown under natural and extended (16 h) photoperiods in a sub-tropical environment at Gatton College, south-east Queensland, under non-limiting conditions of water and nutrient supply. Daily climatic data, and dates of emergence, floral initiation, harvest maturity, together with yield and quality were obtained. Yield and quality responses to temperature and photoperiod were quantified. As growing season mean minimum temperatures decreased, fresh weight of tops decreased while fresh weight harvest index increased linearly. There was no definite relationship between fresh weight of tops or fresh weight harvest index and growing season minimum temperatures greater than 10 C. Genotype, rather than the environment, mainly determined head quality attributes. Fiesta had the best head quality, with higher head shape and branching angle ratings than Greenbelt or Marathon. Bud colour and cluster separation of Marathon were only acceptable for export when growing season mean minimum temperatures were less than 8 C. Photoperiod did not influence yield or quality in any of the three cultivars. A better understanding of genotype and environmental interactions will help farmers optimise yield and quality, by matching cultivars with time of sowing. Crop developmental responses to temperature and photoperiod were quantified from emergence to harvest maturity (Model 1), from emergence to floral initiation (Model 2), from floral initiation to harvest maturity (Model 3), and in a combination of Models 2 and 3 (Model 4). These thermal time models were based on optimised base and optimum temperatures of 0 and 20 C, respectively. These optimised temperatures were determined using an iterative optimisation routine (simplex). Cardinal temperatures were consistent across cultivars but thermal time of phenological intervals were cultivar specific. Sensitivity to photoperiod and solar radiation was low in the three cultivars used. Thermal time models tested on independent data for five cultivars (Fiesta, Greenbelt, Marathon, CMS Liberty and Triathlon) grown as commercial crops on the Darling Downs over two years, adequately predicted floral initiation and harvest maturity. Model 4 provided the best prediction for the chronological duration from emergence to harvest maturity. Model 1 was useful when floral initiation data were not available, and it predicted harvest maturity almost as well as Model 4 since the same base and optimum temperatures of 0 C and 20 C, respectively, were used for both phenological intervals. Model 1 was also generated using data from 1979-80 sowings of three cultivars (Premium Crop, Selection 160 and Selection 165A). When Model 1 was tested with independent data from 1983-84, it predicted harvest maturity well. Where floral initiation data were available, predictions of harvest maturity were most precise using Model 3, since the variation, which occurred from emergence to floral initiation, was removed. Prediction of floral initiation using Model 2 can be useful for timing cultural practices, and for avoiding frost and high temperature periods. This research has produced models to assist broccoli farmers in crop scheduling and cultivar selection in south-east Queensland. Using the models as a guide, farmers can optimise yield and quality, by matching cultivars with sowing date. By accurately predicting floral initiation, the risk of frost damage during floral initiation can be reduced by adjusting sowing dates or crop management options. The simple and robust thermal time models will improve production and marketing arrangements, which have to be made in advance. The thermal time models in this study, incorporating frost risk using conditional statements, provide a foundation for a decision support system to manage the sequence of sowings on commercial broccoli farms.

The environment can exert strong selective pressures on an organism. When selective pressures on traits differ between environments local adaptation may occur. If there is gene flow between the environments, local adaptation may be slowed or prevented. In plants, particularly weedy ephemerals, germination is a life-history trait that can be a strong determinant on fitness. In this dissertation, I explore the germination traits of two weedy Brassicaceae species, Arabidopsis thaliana and Sinapis arvensis, having populations in different habitats to determine whether germination traits within and between populations vary based on environmental conditions and to assess the extent of local adaptation. In Chapter 1, I assessed which genomic regions of A. thaliana were associated with differences in germination traits due to genotype-by-environment interactions. I performed a genome-wide association study using 100 natural accessions of A. thaliana under four light and nutrient combinations. I found 20 single nucleotide polymorphisms significantly associated with different environments, but none associated specifically with genotype-by-environment interactions. In Chapter 2, I assessed germination traits of S. arvensis collected from agricultural and non-agricultural habitats in the Bitterroot Valley of Montana. I discovered that the agricultural collection studied exhibited significantly different germination timing and amounts than the non-agricultural collections, which were statistically indistinguishable from each other. I also found evidence of a strong maternal effect on germination traits. In Chapter 3, I tested whether patterns of genetic variation between agricultural and non-agricultural collections of S. arvensis supported local adaptation to the two habitats even in the face of gene flow. While I expected to see some genetic differentiation between habitats, as seen in Chapter 2, no genetic differentiation was detected and markers putatively under selection were not associated with a particular habitat. I discuss why this might have occurred even though I have evidence for genetically-based phenotypic differentiation between agricultural and non-agricultural populations of S. arvensis. / text

Infection by multiple parasites is a part of everyday life for many organisms. The host immune system may be a central mediator of the many ways parasites might influence one another (and their hosts). Immunity provides a means for the colonized to reduce the success of current and future colonizers and has evolved across the tree of life several times independently. Along the way, the immune systems of plants as well as many groups of animals has evolved perhaps an accidental vulnerability wherein defense against one parasite can increase susceptibility to others. This so-called immune 'cross-talk' is a conundrum worth investigating not only to understand the impact of parasites on focal organisms, but also to better predict how immunity itself influences the evolution and epidemiology of parasites whose spread we might like to curtail. For plants, co-infection often comes from insect herbivores and various bacteria that colonize the leaf interior. Both colonizers can reduce plant fitness directly or indirectly by potentiating future enemies via cross-talk in plant immunity. This phenomenon has largely been studied in laboratory model plants, leaving a substantial gap in our knowledge from native species that interact in the wild. This dissertation helps close this gap by investigating the ecology of co-infection of a native plant by its major insect herbivore and diverse leaf-colonizing bacteria. I revealed that leaf co-infection in the field by leaf-mining herbivores and leaf-colonizing ("phyllosphere") bacteria is substantially more common than single infection by either group and that bacterial infection can cause increased feeding by herbivores in the laboratory. Immune cross-talk can also shape the field-scale patterns of herbivory across a native plant population. Studying the main herbivore of this native plant in detail revealed that, in contrast to many specialist herbivores, our focal species avoids plant defenses likely because it does not possess a specialized means of avoiding their toxicity. Nonetheless, this species may depend on the very same defenses it avoids by being initially attracted to plants that produce them. This foraging strategy is unique among known specialists. Lastly, I moved beyond immune cross-talk to explore how co-occurring phyllosphere bacteria might directly impact one another through competition. In the lab, I found that different growth strategies underlie competitive ability for two major clades of bacteria within the genus Pseudomonas, and that toxin production and resistance may be important mediators of competition within the phyllosphere. However, competitively superior bacteria that produce toxins may indirectly facilitate the survival of inferior competitors through their being toxin resistant, which likely enhances co-existence of diverse bacteria in the phyllosphere. Together, this dissertation has revealed a variety of means by which co-infecting bacteria and insects might influence one another through plant defense cross-talk, as well as how the complex interplay of colonization and competition might affect the structure of leaf microbial communities in nature.

The buildup of salt in soils is a major abiotic stress that affects agricultural productivity, limiting the growth and yield of most crop species which cannot tolerate even modest levels of salinity (glycophytes). Genetic variability for salt tolerance exists as some plants (halophytes) have adapted to environments with high levels of salt. Understanding how salt tolerance has been acquired in halophytic species will be an important part of strategies to improve the ability of crops to grow in saline soils. The CALCINEURIN B-LIKE10 (AtCBL10) calcium sensor was identified as a component of salt signaling in the glycophyte Arabidopsis thaliana (A. thaliana) based on hypersensitivity of the Atcbl10 mutant to salt. When A. thaliana is grown in the presence of salt, AtCBL10 interacts with the AtSOS2 protein kinase to activate the AtSOS1 sodium/proton exchanger, resulting in the removal of sodium ions from the cytosol. Eutrema salsugineum (E. salsugineum), a halophytic relative of A. thaliana, has two CBL10 genes (EsCBL10a and EsCBL10b). In this research, the duplication of CBL10 in E. salsugineum was characterized and the functions of EsCBL10a and EsCBL10b in salt tolerance were determined. My analyses indicate that the coding sequences of EsCBL10a and EsCBL10b are highly conserved, as they share 85% nucleotide identity. An analysis of transcript structure indicates transcripts from EsCBL10a and EsCBL10b loci are alternatively spliced, but in distinct ways. My results suggest that EsCBL10a and AtCBL10 likely share the ancestral genomic position, while EsCBL10b might have moved to a different genomic region, and that the duplication took place prior to the divergence of expanded Lineage II species. The expression patterns of EsCBL10a and EsCBL10b are different; EsCBL10b transcript is high in shoots and low in roots while EsCBL10a transcript is detectable in both tissues. Preliminary analysis of E. salsugineum lines with reduced expression of EsCBL10a and EsCBL10b suggest that both genes might play a role during growth in the presence of salt, but that these roles are distinct.

Studies of demography and population structure give insight into important evolutionary processes such as speciation and diversification. In the present work I perform such studies in the genus Capsella, which has three species: C. grandiflora, an outcrossing diploid, C. rubella a selfing diploid, and C. bursa-pastoris a selfing tetraploid. These three species make a good model system for evolutionary studies because they encompass two major plant evolutionary processes: mating system shifts and polyploidization. To conduct my studies I have gathered a large number of samples across the distributions of each species and scored them both phenotypically and genotypically: more specifically we measured flowering time and collected DNA sequence data. In the tetraploid C. bursa-pastoris we applied an association mapping approach which takes population structure into account to search for genetic variation associated with variation in flowering time. Flowering time is an important and highly adaptive trait which is frequently subject to natural selection. We found evidence of association between flowering time and several single nucleotide polymorphisms (SNPs) within the flowering locus C (FLC) and cryptochrome 1 (CRY1). In the case of FLC these SNPs code for nonconsensus splice site variation in one of the two copies of the gene. The SNPs could potentially have functional consequences and our results imply that non-functionalization of duplicate genes could be an important source of phenotypic variation. Using a novel coalescent based approach, we investigated the polyploid origin of C. bursa-pastoris and find evidence supporting a recent autopolyploid origin of this species. In the two diploid species, I use sequence data to investigate population structure and demographic history and to assess the effects of selfing on C. rubella. Observed patterns of population structure and genetic diversity in C. rubella can be explained by a combination of both demographic history and mating system. Observed patterns in C. grandiflora suggest that the investigated populations do not deviate strongly from the SNM, which has rarely been found in modern demographic studies. Finally, we investigate the effect of sampling strategy on demographic inference. Extensive sampling both within and across our populations allow us to empirically test the effect of sampling strategy on demographic inference. We complement the empirical analysis with simulations and conclude that the effect of sampling strategy is in many cases weak compared with that of demographic events. Nevertheless, these effects are real and have the potential to lead to false inference and therefore sampling strategy should be carefully considered in demographic studies. / Felaktigt tryckt som Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology 725

Broccoli is a vegetable crop of increasing importance in Australia, particularly in south-east Queensland and farmers need to maintain a regular supply of good quality broccoli to meet the expanding market. However, harvest maturity date, head yield and quality are all affected by climatic variations during the production cycle, particularly low temperature episodes. There are also interactions between genotype and climatic variability. A predictive model of ontogeny, incorporating climatic data including frost risk, would enable farmers to predict harvest maturity date and select appropriate cultivar - sowing date combinations. The first stage of this research was to define floral initiation, which is fundamental to predicting ontogeny. Scanning electron micrographs of the apical meristem were made for the transition from the vegetative to advanced reproductive stage. During the early vegetative stage (stage 1), the apical meristem was a small, pointed shoot tip surrounded by leaf primordia. The transitional stage (stage 2) was marked by a widening and flattening to form a dome-shaped apical meristem. In the floral initiation stage (stage 3), the first-order floral primordia were observed in the axils of the developing bracts. Under field conditions, the shoot apex has an average diameter of 500 micro m at floral initiation and floral primordia can be observed under a light microscope. Sub-zero temperatures can result in freezing injury and thereby reduce head yield and quality. In order to predict the effects of frosts, it is desirable to know the stages of development at which plants are most susceptible. Therefore, the effects of sub-zero temperatures on leaf and shoot mortality, head yield and quality were determined after exposure of plants to a range of temperatures for short periods, at different stages of development (vegetative, floral initiation and buttoning). Plants in pots and in the field were subjected to sub-zero temperature regimes from -1 C to -19 C. Extracellular ice formation was achieved by reducing temperatures slowly, at a rate of -2 C per hour. The floral initiation stage was most sensitive to freezing injury, as yields were significantly reduced at -1 C and -3 C, and shoot apices were killed at -5 C. There was no significant yield reduction when the inflorescence buttoning stage was subjected to -1 C and -3 C. Although shoot apices at buttoning survived the -5 C treatment, very poor quality heads of uneven bud size were produced as a result of arrested development. The lethal temperature for pot-grown broccoli was between -3 C and -5 C, whereas the lethal temperature for field-grown broccoli was between -7 C and -9 C. The difference was presumably due to variation in cold acclimation. Freezing injury can reduce broccoli head yield and quality, and retard plant growth. Crop development models based only on simple thermal time without restrictions will not predict yield or maturity if broccoli crops are frost-damaged. Field studies were conducted to develop procedures for predicting ontogeny, yield and quality. Three cultivars, (Fiesta, Greenbelt and Marathon) were sown on eight dates from 11 March to 22 May 1997, and grown under natural and extended (16 h) photoperiods in a sub-tropical environment at Gatton College, south-east Queensland, under non-limiting conditions of water and nutrient supply. Daily climatic data, and dates of emergence, floral initiation, harvest maturity, together with yield and quality were obtained. Yield and quality responses to temperature and photoperiod were quantified. As growing season mean minimum temperatures decreased, fresh weight of tops decreased while fresh weight harvest index increased linearly. There was no definite relationship between fresh weight of tops or fresh weight harvest index and growing season minimum temperatures greater than 10 C. Genotype, rather than the environment, mainly determined head quality attributes. Fiesta had the best head quality, with higher head shape and branching angle ratings than Greenbelt or Marathon. Bud colour and cluster separation of Marathon were only acceptable for export when growing season mean minimum temperatures were less than 8 C. Photoperiod did not influence yield or quality in any of the three cultivars. A better understanding of genotype and environmental interactions will help farmers optimise yield and quality, by matching cultivars with time of sowing. Crop developmental responses to temperature and photoperiod were quantified from emergence to harvest maturity (Model 1), from emergence to floral initiation (Model 2), from floral initiation to harvest maturity (Model 3), and in a combination of Models 2 and 3 (Model 4). These thermal time models were based on optimised base and optimum temperatures of 0 and 20 C, respectively. These optimised temperatures were determined using an iterative optimisation routine (simplex). Cardinal temperatures were consistent across cultivars but thermal time of phenological intervals were cultivar specific. Sensitivity to photoperiod and solar radiation was low in the three cultivars used. Thermal time models tested on independent data for five cultivars (Fiesta, Greenbelt, Marathon, CMS Liberty and Triathlon) grown as commercial crops on the Darling Downs over two years, adequately predicted floral initiation and harvest maturity. Model 4 provided the best prediction for the chronological duration from emergence to harvest maturity. Model 1 was useful when floral initiation data were not available, and it predicted harvest maturity almost as well as Model 4 since the same base and optimum temperatures of 0 C and 20 C, respectively, were used for both phenological intervals. Model 1 was also generated using data from 1979-80 sowings of three cultivars (Premium Crop, Selection 160 and Selection 165A). When Model 1 was tested with independent data from 1983-84, it predicted harvest maturity well. Where floral initiation data were available, predictions of harvest maturity were most precise using Model 3, since the variation, which occurred from emergence to floral initiation, was removed. Prediction of floral initiation using Model 2 can be useful for timing cultural practices, and for avoiding frost and high temperature periods. This research has produced models to assist broccoli farmers in crop scheduling and cultivar selection in south-east Queensland. Using the models as a guide, farmers can optimise yield and quality, by matching cultivars with sowing date. By accurately predicting floral initiation, the risk of frost damage during floral initiation can be reduced by adjusting sowing dates or crop management options. The simple and robust thermal time models will improve production and marketing arrangements, which have to be made in advance. The thermal time models in this study, incorporating frost risk using conditional statements, provide a foundation for a decision support system to manage the sequence of sowings on commercial broccoli farms.

Broccoli is a vegetable crop of increasing importance in Australia, particularly in south-east Queensland and farmers need to maintain a regular supply of good quality broccoli to meet the expanding market. However, harvest maturity date, head yield and quality are all affected by climatic variations during the production cycle, particularly low temperature episodes. There are also interactions between genotype and climatic variability. A predictive model of ontogeny, incorporating climatic data including frost risk, would enable farmers to predict harvest maturity date and select appropriate cultivar – sowing date combinations. The first stage of this research was to define floral initiation, which is fundamental to predicting ontogeny. Scanning electron micrographs of the apical meristem were made for the transition from the vegetative to advanced reproductive stage. During the early vegetative stage (stage 1), the apical meristem was a small, pointed shoot tip surrounded by leaf primordia. The transitional stage (stage 2) was marked by a widening and flattening to form a dome-shaped apical meristem. In the floral initiation stage (stage 3), the first-order floral primordia were observed in the axils of the developing bracts. Under field conditions, the shoot apex has an average diameter of 500 &plusmn; 3 µm at floral initiation and floral primordia can be observed under a light microscope. Sub-zero temperatures can result in freezing injury and thereby reduce head yield and quality. In order to predict the effects of frosts, it is desirable to know the stages of development at which plants are most susceptible. Therefore, the effects of sub-zero temperatures on leaf and shoot mortality, head yield and quality were determined after exposure of plants to a range of temperatures for short periods, at different stages of development (vegetative, floral initiation and buttoning). Plants in pots and in the field were subjected to sub-zero temperature regimes from –1 °C to –19 °C. Extracellular ice formation was achieved by reducing temperatures slowly, at a rate of -2 °C per hour. The floral initiation stage was most sensitive to freezing injury, as yields were significantly reduced at –1 °C and –3 °C, and shoot apices were killed at –5 °C. There was no significant yield reduction when the inflorescence buttoning iv stage was subjected to –1 °C and –3 °C. Although shoot apices at buttoning survived the –5 °C treatment, very poor quality heads of uneven bud size were produced as a result of arrested development. The lethal temperature for pot-grown broccoli was between –3 °C and –5 °C, whereas the lethal temperature for field-grown broccoli was between –7 °C and –9 °C. The difference was presumably due to variation in cold acclimation. Freezing injury can reduce broccoli head yield and quality, and retard plant growth. Crop development models based only on simple thermal time without restrictions will not predict yield or maturity if broccoli crops are frostdamaged. Field studies were conducted to develop procedures for predicting ontogeny, yield and quality. Three cultivars, (‘Fiesta’, ‘Greenbelt’ and ‘Marathon’) were sown on eight dates from 11 March to 22 May 1997, and grown under natural and extended (16 h) photoperiods in a sub-tropical environment at Gatton College, south-east Queensland, under non-limiting conditions of water and nutrient supply. Daily climatic data, and dates of emergence, floral initiation, harvest maturity, together with yield and quality were obtained. Yield and quality responses to temperature and photoperiod were quantified. As growing season mean minimum temperatures decreased, fresh weight of tops decreased while fresh weight harvest index increased linearly. There was no definite relationship between fresh weight of tops or fresh weight harvest index and growing season minimum temperatures > 10 °C. Genotype, rather than the environment, mainly determined head quality attributes. ‘Fiesta’ had the best head quality, with higher head shape and branching angle ratings than ‘Greenbelt’ or ‘Marathon’. Bud colour and cluster separation of ‘Marathon’ were only acceptable for export when growing season mean minimum temperatures were < 8 °C. Photoperiod did not influence yield or quality in any of the three cultivars. A better understanding of genotype and environmental interactions will help farmers optimise yield and quality, by matching cultivars with time of sowing. Crop developmental responses to temperature and photoperiod were quantified from emergence to harvest maturity (Model 1), from emergence to floral initiation (Model 2), from floral initiation to harvest maturity (Model 3), and in a combination of Models 2 and 3 (Model 4). These thermal time models were based on optimised base v and optimum temperatures of 0 and 20 °C, respectively. These optimised temperatures were determined using an iterative optimisation routine (simplex). Cardinal temperatures were consistent across cultivars but thermal time of phenological intervals were cultivar specific. Sensitivity to photoperiod and solar radiation was low in the three cultivars used. Thermal time models tested on independent data for five cultivars (‘Fiesta’, ‘Greenbelt’, ‘Marathon’, ‘CMS Liberty’ and ‘Triathlon’) grown as commercial crops on the Darling Downs over two years, adequately predicted floral initiation and harvest maturity. Model 4 provided the best prediction for the chronological duration from emergence to harvest maturity. Model 1 was useful when floral initiation data were not available, and it predicted harvest maturity almost as well as Model 4 since the same base and optimum temperatures of 0 °C and 20 °C, respectively, were used for both phenological intervals. Model 1 was also generated using data from 1979-80 sowings of three cultivars (‘Premium Crop’, ‘Selection 160’ and ‘Selection 165A’). When Model 1 was tested with independent data from 1983-84, it predicted harvest maturity well. Where floral initiation data were available, predictions of harvest maturity were most precise using Model 3, since the variation, which occurred from emergence to floral initiation, was removed. Prediction of floral initiation using Model 2 can be useful for timing cultural practices, and for avoiding frost and high temperature periods. This research has produced models to assist broccoli farmers in crop scheduling and cultivar selection in south-east Queensland. Using the models as a guide, farmers can optimise yield and quality, by matching cultivars with sowing date. By accurately predicting floral initiation, the risk of frost damage during floral initiation can be reduced by adjusting sowing dates or crop management options. The simple and robust thermal time models will improve production and marketing arrangements, which have to be made in advance. The thermal time models in this study, incorporating frost risk using conditional statements, provide a foundation for a decision support system to manage the sequence of sowings on commercial broccoli farms.

Submitted by Reginaldo Soares de Freitas (reginaldo.freitas@ufv.br) on 2016-03-09T17:11:51Z No. of bitstreams: 1 texto completo.pdf: 3295570 bytes, checksum: 064c6e49c545b7a0b7c59fdc7771c06b (MD5) / Made available in DSpace on 2016-03-09T17:11:51Z (GMT). No. of bitstreams: 1 texto completo.pdf: 3295570 bytes, checksum: 064c6e49c545b7a0b7c59fdc7771c06b (MD5) Previous issue date: 2015-02-12 / Conselho Nacional de Desenvolvimento Científico e Tecnológico / A couve-flor (Brassica oleracea L. var botrytis L.) é uma olerícola de importância econômica para pequenos produtores brasileiros. Além das condições climáticas, os manejos da adubação e da água influenciam na qualidade e na produtividade da couve-flor. O nitrogênio é responsável pelo desenvolvimento rápido e vigoroso da inflorescência. O monitoramento das condições hídricas é necessário de modo a garantir o bom desenvolvimento, a fitossanidade, a qualidade e a produtividade das culturas. Neste trabalho teve-se como objetivo avaliar o efeito da aplicação de lâminas de irrigação e de doses de nitrogênio na produção da cultura da couve-flor híbrida Barcelona CMS. O experimento foi conduzido numa área experimental do campus da Universidade Federal de Viçosa (UFV), em Viçosa, MG. Amostras de solo foram coletadas na área experimental para determinação de suas características físicas e químicas. A adubação de plantio foi feita conforme recomendações para a cultura no estado de Minas Gerais. O transplantio das mudas foi feito em 14 de agosto de 2014, aos 38 dias após semeadura (DAS), com espaçamento de 70 cm x 50 cm, totalizando 24 plantas por parcela. Foi instalado um sistema de irrigação por gotejamento com linhas laterais dispostas paralelamente às fileiras de plantas, com um gotejador por planta, com vazão média de 2,24 L h-1. A uniformidade de aplicação de água do sistema de irrigação foi avaliada, obtendo-se valores de CUC e CUD iguais a 94,51 e 91,57%, respectivamente. Os valores diários de evapotranspiração de referência (ET0) foram calculadas com uso de uma estação meteorológica automática e do programa 6 computacional REF-ET, com aplicação da equação de Penman-Monteith FAO 56. Os coeficientes de cultura (Kc) utilizados foram iguais a 0,45; 0,80; 1,05 e 0,90 para os estádios de desenvolvimento I, II, III e IV respectivamente. A irrigação foi conduzida com turno de rega diário. A adubação nitrogenada foi feita com ureia, sendo aplicados 20% de cada dose estudada aos 17 dias após o transplantio (DAT), 40% aos 31 e 40% aos 45 DAT. Foi adotado o esquema de parcelas subdivididas, no delineamento inteiramente casualizado (DIC), tendo nas parcelas as lâminas (0; 75; 100; 125 e 150 % da ETc) e nas subparcelas as doses de nitrogênio (0; 75; 150; 300 e 450 kg ha-1). Foram avaliados na inflorescência: massa fresca (MFI), produtividade total (PT), massa seca (MSI), percentagem de matéria seca (PMSI), diâmetro (DI), altura (AI), porcentagem de matéria seca alocada (PMSAI) e porcentagem de nitrogênio (PNI); no caule: massa fresca (MFC), massa seca (MSC), percentagem de matéria seca (PMSC), porcentagem de matéria seca alocada (PMSAC) e porcentagem de nitrogênio (PNC); e nas folhas, foram avaliados número (NF), massa média de folhas frescas (MMFF), massa fresca (MFF) e massa seca (MSF), percentagem de matéria seca (PMSF), porcentagem de matéria seca alocada (PMSAF) e o porcentagem de nitrogênio (PNF). Para analisar os efeitos do manejo da irrigação e da adubação sobre as características avaliadas, foram determinados modelos de regressão baseados na significância dos coeficientes de regressão, utilizando o teste t a 5% de probabilidade e no coeficiente de determinação. Verificou-se que o híbrido Barcelona apresentou maior efeito da lâmina de irrigação do que da adubação nitrogenada para a maioria das características estudadas. Também foi verificado efeito quadrático de lâmina e linear de doses nas características MMFF, MFF, PMSF, DI, AI, MFI, PT, PMSI e MFC. Não foi verificado efeito dos fatores em estudo nas características NF, PMSC e MSC. Nas variáveis MMFF, MFF, DI, AI, MFI, PT e MFC, ao se fixar a dose de adubação, as lâminas críticas que determinam valores máximos foram 137,9; 139,2; 128,7; 108,2; 132,4; 132,4; 121,3% da ETc, respectivamente. Já para PMSF e PMSI os valores mínimos foram obtidos nas lâminas críticas de 123,7 e 110,7% da ETc, respectivamente. As lâminas e doses crescentes aumentaram linearmente as produções de MSF e MSI, sendo os valores máximos estimados correspondentes a 158,00 e 75,30 g/planta, respectivamente. A maior produtividade total da couve-flor Barcelona obtida foi 24.547,80 kg ha-1, com diâmetro médio de 19,60 cm, altura média de 14,00 cm e massa fresca da inflorescência de 858,90 g/planta, na lâmina de irrigação equivalente de 132,4% da ETc e na dose de 450 kg ha-1 de N. / Cauliflower (Brassica oleracea L. var botrytis L.) is one of the vegetable crops of economic importance cultivated in Brazil, especially for smallholders. Beyond climate conditions, the fertilizer and water management influence the quality and productivity of cauliflower. The nitrogen is responsible for a good quick and vigorous vegetative growth. The water conditions monitoring is necessary to ensure the good development, plant health, quality and yield. In this study we aimed to verify the effect of water depth and nitrogen application on the Barcelona CMS cauliflower production. The experiment was conducted at the experimental area of the Universidade Federal de Viçosa (UFV), in Viçosa-MG. Soil samples were collected in the experimental area to determine the physical and chemical soil characteristics. The planting fertilization was performed as recommended for the crop in the state of Minas Gerais. The seedlings transplanting was held in August 14, 2014, 38 days after sowing (DAS), with spacing of 70 cm x 50 cm, totaling 24 plants. The irrigation drip system was installed, it was consisting of a prepared lateral lines to the planting line with one dripper per plant and with an average flow rate of 2.24 L h-1. The water uniformity in the irrigation system was evaluated, obtaining CUC and CUD values equal to 94.51 and 91.57%, respectively. The daily values of reference evapotranspiration (ET0) were estimated using a weather station and the REF-ET computer program, based on the Penman-Monteith FAO 56. The crop coefficients (Kc) used were equal to 0.45; 0.80; 1.05 and 0.90 for the I, II, III and IV development stages respectively. Irrigation was performed with daily irrigation 8 schedule. Nitrogen fertilization was made with urea and 20% of each dose studied was applied at 17 days after transplanting (DAT), 40% at 31 and 40% at 45 DAT. The installment scheme subdivided parcel in a completely randomized design (CRD) was adopted; in the plot the depths (0, 75, 100, 125 and 150% of ETc) and the subplots nitrogen rates (0, 75, 150, 300 and 450 kg ha-1). In the inflorescence, we were assessed fresh weight (MFI), total productivity (PT), dry weight (MSI), dry matter percentage (PMSI), diameter (DI) and height (AI); allocated dry matter percentage (PMSAI) and nitrogen percentage (PNI), in the stem: fresh weight (MFC), dry weight (MSC), dry matter percentage (PMSC); nitrogen percentage (PNC) and in the leaves, we were evaluated number (NF), average weight of fresh leaves (MMFF), fresh weight (MFF), dry weight (MSF), dry matter percentage (PMSF) and nitrogen percentage (PNF). To analyze the irrigation and fertilization management effects on these characteristics we determined regression models based in the regression coefficients significance, using the t test at 5% probability and the determination coefficient. This study verified that the Barcelona hybrid had the highest effect of irrigation depths than the nitrogen fertilization for the most traits. It was also verified quadratic effect of depths and linear doses on MMFF, MFF, PMSF, DI, AI, MFI, PT, PMSI, PNI, MFC and PNC. There was no effect of factors under study on the characteristics NF, PNF, PMSC and MSC. In the variables MMFF, MFF, DI, AI, MFI, PT, MFC to be fixed the fertilization level application, the critical depths that determine maximum values were 137.9; 139.2; 128.7; 108,2; 132.4; 132.4; 121.3% of ETc, respectively. Already for PMSF, PMSI, PNI and PNC, the minimum values are obtained in the critical depths 123.7; 110.7; 100.0 and 108.3% of ETc, respectively. The MSF and MSI productions increased linearly with depths and doses increasing and the estimated maximum values corresponding to 158.00 and 75.30 g/plant, respectively. The biggest total productivity obtained was 24,547.80 kg ha-1, with average mean diameter of 19.60 cm, mean height of 14.00 cm, and mean fresh weight 858.90 g/plant, in equivalent irrigation depth of 132.4% of ETc and at a dose of 450 kg ha-1 of N.

Made available in DSpace on 2014-06-11T19:32:05Z (GMT). No. of bitstreams: 0 Previous issue date: 2011-06-27Bitstream added on 2014-06-13T20:22:57Z : No. of bitstreams: 1 silva_rj_dr_jabo.pdf: 999654 bytes, checksum: 9b9706815aad595ba6fd6e0dea74a998 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / O parasitoide Diaeretiella rapae (McIntosh) é considerado um importante inimigo natural de pulgões em culturas de brassicáceas, apresentando potencial como agente de controle biológico desses insetos-praga. O presente estudo visou obter informações sobre D. rapae para subsidiar o desenvolvimento de programas de controle biológico de pulgões em cultivos de brassicáceas. Foram considerados os seguintes objetivos específicos: a) avaliar a qualidade hospedeira de Myzus persicae (Sulzer), Lipaphis erysimi (Kaltenbach) e Brevicoryne brassicae (L.); b) determinar as exigências térmicas; c) determinar as tabelas de vida de fertilidade em diferentes temperaturas e d) avaliar o efeito do armazenamento à baixa temperatura. Para condução dos experimentos e criação das espécies de pulgões e parasitoide utilizaram-se plantas de couve-manteiga (Brassica oleracea var. acephala) Da Geórgia. A qualidade hospedeira foi investigada utilizando-se câmara climatizada regulada a 25 ± 1ºC, 60 ± 10% UR e 12 horas de fotofase e considerando-se as seguintes variáveis biológicas de D. rapae: parasitismo, períodos de desenvolvimento, porcentagem de emergência de adultos, razão sexual, longevidade e tamanho. As exigências térmicas e tabelas de vida de fertilidade foram determinadas em câmaras climatizadas reguladas a 15, 20, 25 e 30 ± 1 ºC, 60 ± 10% UR e 12 horas de fotofase. Para o armazenamento à baixa temperatura utilizou-se câmara climatizada sob temperatura constante de 5 ± 1°C nos seguintes períodos: 0, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 28, 30, 32, 34 e 36 dias. Entre as espécies de pulgões estudadas M. persicae foi a que proporcionou maior qualidade a D. rapae. O limite térmico inferior de desenvolvimento (Tb) e a constante térmica (K) do parasitoide foram 4,0°C e 245,3 GD, respectivamente. A temperatura afetou o desempenho reprodutivo de D. rapae, sendo 25°C... / The parasitoid Diaeretiella rapae (McIntosh) is considered an important natural enemy of aphids in Brassicaceae, showing potential as a biological control agent of insect pests. This study aimed at obtaining information about D. rapae to subsidize the development of programs for biological control of aphids in Brassicaceae. Were considered the following specific objectives: a) to assess the host quality Myzus persicae (Sulzer), Lipaphis erysimi (Kaltenbach) and Brevicoryne brassicae (L.), b) to determine the thermal requirements, c) to determine the fertility life tables at different temperatures and d) to evaluate the effect of storage at low temperature. The experiments and rearing of parasitoid and aphid species were conducted using cabbage plants (Brassica oleracea var. acephala) Da Geórgia. The host quality was investigated using climate chamber at 25 ± 1 º C, 60 ± 10% RH and 12 h photophase and considering the following biological variables of D. rapae: parasitism, developmental periods, percentage of adult emergence, sex ratio, longevity and size. The thermal requirements and fertility life tables were determined in climatic chambers at 15, 20, 25 and 30 ± 1 º C, 60 ± 10% RH and 12 hours photophase. The storage at low temperature was determined under constant temperature of 5 ± 1 ° C in the following periods: 0, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 28, 30, 32, 34 and 36 days. Among the aphid species studied M. persicae showed high quality to D. rapae. The lower thermal threshold (Tb) and thermal constant (K) of the parasitoid were 4.0 °C and 245.3 GD, respectively. The temperature affected the reproductive performance of D. rapae, 25 ° C provided the best thermal conditions for the population growth of the specie. The storage of D. rapae at 5 °C for up to 32 days does not negatively affect the emergence and survival. The storage up to 36 days did not influence... (Complete abstract click electronic access below)

Made available in DSpace on 2014-06-11T19:34:59Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-04-26Bitstream added on 2014-06-13T19:44:45Z : No. of bitstreams: 1 rosa_dd_dr_botfca.pdf: 3769642 bytes, checksum: 6f5fb83fe76a081fea96b890323e30f2 (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Dentro do setor de horticultura, as plantas da família Brassicaceae são de grande expressão, tanto em volume, como em valor agregado na comercialização, por isso, destaca-se o cultivo intensivo de brassicas, como as variedades de Brassica oleraceae L. (Couve, repolho, Couve-flor, Brócolos, Couve de Bruxelas), Brassica napus L. e Brassica oleraceae L. var. pekinensis L. (Couve chinesa), sendo a base de sustentação econômica dos pequenos e médios produtores de hortaliças. Como outras culturas de plantio intensivo, as brassicas também enfrentam inúmeros problemas com doenças, dentre estes está a “hérnia das crucíferas”, doença de enorme risco potencial ao produtor, visto seu difícil ou inexistente controle e por condenar a área, impedindo futuros cultivos de brassicas. O agente causal da “hérnia das crucíferas” (Plasmodiophora brassicae Woronin) é um endoparasita obrigatório, pertencente ao reino Protozoa, habitante do solo, sendo um dos fitopatógenos de solo menos estudados no mundo, mas sabe-se que este apresenta raças patogênicas, ou patotipos, sendo que algumas dessas já são conhecidas, principalmente os que ocorrem na Europa e no Japão sabem-se, também, que estas raças “quebram”, com certa freqüência, a pouca resistência que os melhoristas conseguem incorporar nas variedades comerciais, fazendo com que quase não haja variedade resistente disponível no mercado, principalmente ao mercado brasileiro onde, possivelmente, haja raças ainda não relatadas. O objetivo deste estudo visou conhecer a variabilidade genética e patogênica de isolados de P. brassicae oriundos das principais regiões produtoras de Brassicas do estado de São Paulo, utilizando para isso: a) testes em variedade diferenciais, nacionais e importadas, com isolados monospóricos e não monospóricos para determinação das raças; b) estudo da agressividade dos isolados frente... / Within the horticulture sector, the plants of the Brassicaceae family are widespread in both volume and value-added marketing, so we highlight the intensive cultivation of brassicas, such as varieties of Brassica oleracea L. (Kale, cabbage, cauliflower, broccoli, Brussels sprouts), Brassica napus L. and Brassica oleracea L. var. pekinensis L. (Chinese cabbage), and the basis of economic support for small and medium producers of vegetables. Like other intensive planting crops, the brassicas are also facing many problems with diseases, among these is the club root, disease of great potential risk to the producer, because its difficult or no control and order the area, preventing future crops brassicas. The agent causal of the club root (Plasmodiophora brassicae Woronin) is an obligatory endoparasites belonging to the kingdom Protozoa, inhabitant of soil, being one of the pathogens in soil less studied in the world, but it is known that this presents pathogenic races, or pathotypes, and some of these are already known, especially those taking place in Europe and Japan knows it, too, that these races break with some frequency, the little resistance that breeders can incorporate into commercial varieties, making that almost no resistant variety available in the market, especially the Brazilian market where perhaps there is not race related. This study aimed to investigate the genetic variability and pathogenic isolates of P. brassicae come from the main producing regions Brassicas state of Sao Paulo, using for this: a) testing range differential, domestic and imported, with no single spores and spore for the determination of races, b) study of the aggressiveness of the isolates in the face of cultivars available in the market, c) study of genetic variability within and between populations, using markers RAPD and Microsatellite d) genetic characterization through sequencing of genetic regions... (Complete abstract click electronic access below)