Rozprawy doktorskie: „Brassica rapa”

1

Lopes, Alexandra de Pinho Noites. "Caracterização química e biológicada pieris brassicae alimentada com Brassica Ra pa Var. Rapa". Master's thesis, Faculdade de Farmácia da Universidade do Porto, 2008. http://hdl.handle.net/10216/20825.

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Lopes, Alexandra de Pinho Noites. "Caracterização química e biológicada pieris brassicae alimentada com Brassica Ra pa Var. Rapa". Dissertação, Faculdade de Farmácia da Universidade do Porto, 2008. http://hdl.handle.net/10216/20825.

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Devlin, Paul Francis. "Photomorphogenesis of the ein mutant of Brassica rapa". Thesis, University of Leicester, 1995. http://hdl.handle.net/2381/35451.

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Several phytochrome-controlled processes have been examined in etiolated and light-grown seedlings of a normal genotype and the elongated internode (ein/ein) mutant of rapid cycling Brassica rapa. Etiolated ein seedlings displayed a selective deficiency in response to prolonged red light with respect to inhibition of hypocotyl elongation, expansion of cotyledons and synthesis of anthocyanin. In contrast to normal seedlings, light-grown ein seedlings did not show a growth promotion in response to end-of-day far-red irradiation. Additionally, whereas the first internode of light-grown normal seedlings showed a marked increase in elongation in response to reduced red:far-red ratio, ein seedlings showed only a small elongation response. Immunochemical analysis has demonstrated that the ein mutant lacks a detectable phytochrome B-like protein. Furthermore, analysis at the DNA level has demonstrated the presence of a lesion within the promoter region of the PHYB gene of ein. Both physiological and molecular evidence strongly suggest, therefore, that EIN=PHYB. In common with other photoreceptor mutations, the ein mutation has been shown to be semi-dominant. EIN/ein heterozygote seedlings contain about 50% of the level of immunodetectable phytochrome B of equivalent normal, EIN/EIN seedlings. Etiolated seedlings of the EIN/ein heterozygote show a responsiveness to red light almost exactly intermediate between that of ein/ein and EIN/EIN homozygotes. The response of the EIN/ein heterozygote both to low red:far-red ratio light and to end-of-day far-red light treatments is also intermediate between that of the homozygotes EIN/EIN and ein/ein A range of other phytochrome-controlled responses have been examined in normal and ein seedlings which have further elucidated the roles played by phytochrome B in rapid cycling B. rapa, whilst shedding light on the actions of other phytochrome species. Finally, a method for the transformation of rapid cycling B. rapa has been investigated, demonstrating the potential for the creation of transgenic phytochrome mutants in rapid cycling B. rapa.

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Stadel, Tyler John. "Selection for Low Calcium Tolerance in Brassica rapa". Thesis, North Dakota State University, 2018. https://hdl.handle.net/10365/29230.

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Ecosystems across a landscape can vary in their selection pressures and therefore can vary in the species that are able to survive there. Selection pressures applied on a species found in multiple ecosystems may lead to a divergence into different taxa adapted to different selective conditions. One such soil condition with strong selection pressures are serpentine soils. They are unique in that they have low levels of essential nutrients, specifically calcium, and high levels of heavy metals. To examine the effect of serpentine-like conditions on a model plant species, I grew Brassica rapa in a low calcium hydroponic environment and selected the most tolerant individuals within a population. After three generations, life history variables didn?t change in comparison to controls, except dry mass. This could indicate that this population is at the beginning of a longer term evolutionary divergence. More generations of selection are needed to confirm this idea.

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Bell, P. E. C. "Evolutionary dynamics of domestication : the case of Brassica rapa". Thesis, University of Cambridge, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.596539.

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The presence of three B. rapa forms in the UK provides an opportunity for a unique study of the relationships between cultivated B. rapa, and weedy and wild derived from them - the escape from cultivation. A range of morphological characters have been studied along with the DNA markers, AFLP and microsatellites, using the same plant material. Morphological characters discriminated between wild, weedy and cultivated forms of B. rapa. Within the cultivated group, the morphological analysis separates B. rapa var oleifera winter and spring turnip oil seed rape varieties. B. rapa var rapa stubble turnip varieties are separated from root turnip. Based on morphological analysis wild and weedy groups are differentiated, but this is not supported by AFLP analysis. AFLPs, as neutral markers, reflect the agricultural histories of B. rapa cultivars. All B. rapa var. rapa and var. oleifera cultivars clustered together in principal co-ordinate plots, although two accessions of vars. rapa clustered with wild and weedy forms (traditional cultivars, ‘Hardy Green Round’ and ‘Lincolnshire Red Globe’). Significant levels of genetic variation was observed in all B. rapa accessions. Genetic evidence indicates that weedy B. rapa is derived from wild plants not directly from cultivars. The microsatellite analysis indicated significant distinctions in allele frequency between wild, weedy and cultivated forms. The population structure of cultivated and weedy B. rapa was distinct from the wild group, with much enhanced homozygosity. Inbreeding and founder effects may be important factors here. Some plants of wild B. rapa growing adjacent to B. napus show intermediate DNA and morphological phenotypes. This indicates natural hybridisation and backcrossing.

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Bell, Philippa Emily Clements. "The dynamics of domestication : the case of Brassica rapa". Thesis, University of Cambridge, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.614234.

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Wang, Tongtong. "Resistance to Turnip mosaic virus (TuMV) in Brassica juncea and introgression of resistance from Brassica rapa, Brassica napus and Brassica nigra into Brassica juncea". Thesis, University of Warwick, 2016. http://wrap.warwick.ac.uk/89272/.

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Turnip mosaic virus (TuMV, family Potyviridae, genus Potyvirus) has the widest host range amongst potyviruses. Globally it was said to be the second most important virus infecting field vegetables. Brassica juncea (Oriental mustard, family Brassicaceae), is an amphidiploid plant species with the genome AABB, comprising the genomes of the two diploid species, Brassica rapa (AA) and Brassica nigra (BB). It is widely grown and has various uses including as a leaf, stem, or root vegetable, oilseed crop, forage crop, condiment and biofumigant. Most B. juncea cultivars are very susceptible to TuMV, resulting in severe losses. Research on TuMV resistance and the mapping and identification of natural resistance genes would be very useful in order to speed up breeding resistant crops through marker-assisted selection. Sources of resistance to TuMV have been identified in B. juncea. The specificity of the resistances has been determined. A B. juncea DH line for which there is genomic information has been challenged with TuMV and found to be susceptible. This line has been used as a susceptible parent in crosses with resistant plants derived from different sources to develop segregating populations for mapping the resistance gene(s). Two BC1 populations (222 plants and 205 plants) and one F2 population (159 plants) have been phenotyped and segregation ratios were not significantly different from a Mendelian model based on the action of two recessive genes. Parental lines and selected plants in the two BC1 populations have been analysed by SNPs genotyping using the Illumina Infinium Chip. Genetic linkage maps have been constructed and QTLs have been mapped. Additionally, attempts are being made to identify a dominant TuMV resistance gene present in both Brassica napus and B. rapa. Inter-specific crosses have been made in order to introgress this gene into B. juncea. Resynthesised B. juncea plants possessing this dominant resistance have been produced through embryo rescue and polyploidy induction of F1 plants from crosses between resistant B. rapa and susceptible B. nigra plants. BC2 plants have also been developed by crossing B. rapa and B. napus plants possessing the dominant TuMV resistance with a susceptible B. juncea plant line.

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8

Kubik, Thomas James. "Evaluation of doubled haploid lines derived from interspecific crosses between Brassica napus and Brassica rapa". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp01/MQ40073.pdf.

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Stadnyk, Kimberly D. "Improvement on the microspore culture methodology for Brassica rapa canola". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp01/MQ41780.pdf.

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Cuthbert, Patricia Anne. "Genetic analysis of blackleg and white rust resistance in Brassica rapa". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape2/PQDD_0022/MQ51699.pdf.

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Lima, André Oliveira. "Biofumigação do solo com Brassica rapa para o controle de fitonematóides". Universidade Federal de Viçosa, 2006. http://locus.ufv.br/handle/123456789/4408.

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The root knot nematodes, belonging to the genus Meloidogyne Goeldi, 1887, are economically most important group of plant nematodes in the agriculture, producing knobs or galls on the roots of host plants. The losses are greater when infection occurs at the seedling stage. In the botanical family there are species like that of wild mustard (Brassica rapa), that contain glucosinolates, which after enzymatic hydrolyses can generate toxic volatile compounds such as isothiocyanates. It is believed that the incorporation of mustard tissues controls plant nematodes present in the planting substrates used in nursery and seedling production and in the small areas destined for vegetable crops. Thus this can be a viable alternative to the synthetic soil fumigants such as methyl bromide that are harmful to the environment. To evaluate the biofumigant potential of mustard in the management of plant nematodes, dried leaves, seed meal and defatted seed meal were studied to find the efficient tissue and the dose to be incorporated to the substrate to control Meloidogyne incognita. After determining the ideal tissue and the dose they were also used to study the in vitro effect on the mortality of Heterodera glycines, M. javanica, M. exigua, M. mayaguensis and M. incognita. The biofumigant effect was evaluated on the general microbial population of soil. The amount of allyl isothiocyanate liberated in the soil was also determined. The leaves, seed meal and defatted seed meal efficiently controlled M. incognita, but the defatted seed meal proved to be most efficient. The nematicidal effect of mustered was attributed to the volatile compounds. The defatted seed meal efficient in causing the mortality of juveniles of all the nematode species tested. The dehydrated mustard leaves when incorporated into the soil increased the population of bacteria and actinomycetes. The maximum of allyl isothiocyanate was liberated by the defatted seed meal during the biofumigation process. It was concluded that the use of mustard as biofumigant is a viable alternative to control plant nematodes and has the potential to substitute the methyl bromide for seedling substrates treatment.
Os nematóides das galhas, pertencentes ao gênero Meloidogyne Goeldi, 1887, constituem o grupo de fitonematóides com maior importância econômica na agricultura, causando a formação de galhas em raízes hospedeiras. Os prejuízos são maiores quando a infecção ocorre ainda na fase de mudas. A família Brassicaceae tem representantes como a mostarda (Brassica rapa), que produzem glucosinolatos, que ao sofrerem hidrólise enzimática vão gerar produtos tóxicos como os isotiocianatos. Acredita-se que sua incorporação permitirá o controle de fitonematóides presentes em substratos para viveiros e em pequenas áreas destinadas ao cultivo de olerícolas. Assim, esta pode ser uma alternativa viável ao uso de fumigantes sintéticos, como o brometo de metila, prejudiciais ao meio ambiente. Para avaliar o potencial biofumigante da mostarda no manejo de fitonematóides, folha desidratada, farinha de sementes e farinha de sementes desengordurada foram estudados para determinar a melhor dose destes produtos a ser incorporada ao solo visando o controle de Meloidogyne incognita. Conhecidas as doses, estas foram utilizadas para avaliar o efeito in vitro sobre a mortalidade de Heterodera glycines, M. javanica, M. exigua, M. mayaguensis e M. incognita. A ação biofumigante da mostarda foi avaliada sobre populações microbianas do solo, assim como a quantificação de isotiocianato de alila liberado no solo durante o processo de biofumigação. Folha, farinha de sementes e farinha de sementes desengordurada foram eficientes no controle de M. incognita, sendo que a farinha de sementes desengordurada foi a que apresentou melhores resultados. Foi possível comprovar que o efeito nematicida da mostarda se deve aos seus subprodutos voláteis, e foi verificada a sua eficiência em causar a morte dos juvenis de todas as espécies de nematóides testadas. A folha de mostarda ao ser incorporada ao solo aumentou o número de ufc s de bactérias e actinomicetos. A farinha de sementes desengordurada apresentou as maiores quantidades de isotiocianato de alila liberadas durante a fumigação. Conclui-se que o uso da mostarda como biofumigante de solo é uma alternativa para o controle de fitonematóides e apresenta potencial para a substituição do brometo de metila no tratamento de solo e substratos.

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Bassegio, Doglas [UNESP]. "Potencial produtivo de acessos de espécies brássicas sob condições tropicais". Universidade Estadual Paulista (UNESP), 2017. http://hdl.handle.net/11449/150299.

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O gênero Brassica é a terceira maior fonte de óleo vegetal do mundo, com oleaginosas cultivadas no Hemisfério Norte. No Brasil, apesar do aumento nos últimos anos, a espécie Brassica napus L., não é um cultivo tradicional, devido as limitações de fotoperíodo e altas temperaturas. Outras espécies do gênero, como é o caso da Brassica juncea L. e Brassica rapa L., amplamente cultivadas em zonas de baixa precipitação e fertilidade, podem ser opções de cultivo em áreas marginais de sequeiro em condições tropicais, visto que possuem alto teor de óleo com características propicias para o biodiesel, além de menor sensibilidade ao ambiente. Os objetivos deste trabalho foram caracterizar germoplasma de Brassica juncea L. e Brassica rapa L., avaliar o potencial produtivo e a divergência genética de acessos em Botucatu – SP, Brasil. Os experimentos tiveram início em outono-inverno de 2012, com a avaliação de 424 acessos de Brassica juncea L. e 209 de Brassica rapa L. quanto ao florescimento e produção de sementes. Em outono-inverno de 2015 e 2016 acessos de brássicas e um híbrido comercial da espécie Brassica napus L. foram avaliados, em experimentos em blocos ao acaso com três repetições, em relação aos componentes da produção, à produção grãos e óleo e a divergência genética. Do total de acessos introduzidos e avaliados, apenas 51 (12%) de Brassica juncea L. e 59 (28%) de Brassica rapa L. produziram sementes, devido ao efeito de fotoperiodo. Os componentes da produção variaram entre acessos e espécies, com destaque para precocidade e teor de óleo de acessos da espécie Brassica rapa L.; e o número de síliquas e a produtividade de grãos e óleo de acessos da espécie Brassica juncea L.. A produtividade de grãos e óleo foi em média 15% superior nos acessos de Brassica juncea L. em relação a espécie Brassica rapa L., com destaque para o acesso PI 180266 com 2056 kg ha–1 de grãos e 805 kg ha–1 de óleo. A variabilidade genética entre os acessos de brássicas possibilitou a formação de grupos de acessos para futuros ganhos em melhoramento genético. Conclui-se que os acessos selecionados confirmam a hipótese do potencial produtivo sem efeito de fotoperíodo em condições tropicais, o que demonstra que podem ser opções para cultivo em áreas onde a Brassica napus L. não está bem adaptada.
Brassica is the third largest source of vegetable oil in the world, with oilseeds grown in the Northern Hemisphere. In Brazil, despite the increase in recent years, Brassica napus L., is not a traditional crop due to limitations of photoperiod and high temperatures. Other species of the genus, such as Brassica juncea L. and Brassica rapa L., widely cultivated in low rainfall zones and fertility, may be cultivation options in marginal rainfed areas under tropical conditions, since they have high oil content with characteristics conducive to biodiesel, in addition to lower sensitivity to environment. The objectives of this work were to characterize the germplasm of Brassica juncea L. and Brassica rapa L. and to evaluate the productive potential, as well as the genetic divergence of accesses in Botucatu – SP, Brazil. The experiments started in autumn-winter of 2012, with the evaluation of 424 accessions of Brassica juncea L. and 209 of Brassica rapa L. regarding flowering and seed production. In the autumn-winter of 2015 and 2016, Brassica napus L. and commercial Brassica napus L. were evaluated in randomized blocks with three replicates, in relation to the production components, grain and oil production, and divergence genetic. Of the total number of accesses introduced and evaluated, only 51 (12%) of Brassica juncea L. and 59 (28%) of Brassica rapa L. produced seeds, due to the effect of photoperiod. The components of the production varied between accesses and species, with emphasis on precocity and oil content of Brassica rapa L.; and the growth and number of siliques of the specie Brassica juncea L. The yield of grains and oil was on average 15% higher in the accessions of Brassica juncea L. in relation to the species Brassica rapa L., with emphasis on access PI 180266 with 2056 kg ha–1 of grains and 805 kg ha–1 of oil yield. The genetic variability among the accessions of brassicas allowed the formation of groups of accessions for future gains in genetic improvement. It is concluded that the selected accessions confirm the hypothesis of the productive potential without photoperiod effect in tropical conditions, which demonstrates that they can be options for cultivation in areas where Brassica napus L. is not well adapted.

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13

Miller, Trevor Allan. "Agronomic and quality performance of three doubled haploid lines derived from a Brassica napus/Brassica rapa interspecific cross". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/MQ60470.pdf.

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Friesen, Holly A. "The application of doubled haploid plants to population improvement in Brassica rapa". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/mq23311.pdf.

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Barbosa, Patrícia Souza. "Influência do cádmio em parâmetros bioquímicos e de crescimento de nabiças (Brassica rapa)". Master's thesis, ISA/UTL, 2011. http://hdl.handle.net/10400.5/4113.

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Mestrado em Engenharia Alimentar - Instituto Superior de Agronomia
In this work the response of Brassica rapa to cadmium induced oxidative stress was studied, both in hydroponic solution (with Cd concentrations of 10 and 25 μM) and in turf (10 μM). The following parameters were studied: plant length, number of leaves, fresh and dry weight of leaves and roots, mineral elements concentration (Cd, Na, K, Ca, Mg, Zn, Mn and Fe), MDA and H2O2 levels and chlorophyll content. The Cd contents in leaves were significantly higher in plants growing in hydroponic solution than in turfs, because Cd is more available in nutrient solution. The minerals mainly affected by Cd were Zn, Fe and Na, whose content in leaves decreased significantly when plants were grown in 25 μM Cd. In plants growing in 10 μM Cd, in hydroponic solution, an increase in H2O2 levels was detected. A higher level of lipid peroxidation was also detected in plants growing in Cd containing solution. It can be concluded that B. rapa plants, even when exposed to a concentration of 25 μM Cd, are not visually affected by Cd toxicity, although its leaves contain significant amounts of Cd, which can represent a danger for the consumer as the plants continue to look healthy.

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Persson, Karin. "Genetic diversity in landraces of rye (Secale cereale L.) and turnip (Brassica rapa L. ssp. rapa) from the Nordic area /". Alnarp : Swedish Univ. of Agricultural Sciences (Sveriges lantbruksuniv.), 2000. http://epsilon.slu.se/avh/2000/91-576-5773-4.pdf.

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Herrera, Díaz Areli. "Regeneration and plastid transformation approaches in Arabidopsis thaliana and Rapid-Cycling Brassica rapa". Diss., lmu, 2011. http://nbn-resolving.de/urn:nbn:de:bvb:19-134542.

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Bless, Yo-Neal. "Modulation of brassica rapa L. antioxidant activities by exogenous methylglyoxal under zirconium stress". University of the Western Cape, 2016. http://hdl.handle.net/11394/4961.

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>Magister Scientiae - MSc
With a decrease in water availability and arable land, and the ever-increasing reports of toxic chemical pollutants, it is crucial to elucidate plants’ mechanisms of adaptability to these abiotic stressors. South Africa alone accounts for approximately 30% of global Zirconium (Zr) production. However, reports on Zr-induced stress in plants are sparse. Increased mining activity leads to soil contamination which subsequently has harmful effects on crop plants. Under normal conditions B. rapa crop plants flourish, they are rapid in their cycling and circumvent the seed dormancy stage which enables them to have high yields over relatively short periods. However, when unfavourable conditions arise, such as exposure to toxic chemicals and metal ions like Zirconium, the development and growth of B. rapa L., much like other crop plants is affected. More specifically, the damaging effects of Zr is not only attributed directly; as with substitutions of biometals [like Iron (Fe)] in various biomolecules rendering them inactive, but more as a consequence of the production of toxic molecules such as reactive oxygen species (ROS) and methylglyoxal (MG). ROS such as superoxide anion (O₂⁻) and hydrogen peroxide (H₂O₂ ) are known to have signalling roles in plants with reports on their involvement in alleviating seed dormancy and seedling development. However, the signalling roles of MG are not known with regards to plant cells and have been reported more so in animal cells; playing vital roles in fat signalling in diseases such as diabetes. Furthermore MG, in plant and animal cells, directly converts oxygen (O₂) to O₂⁻ and thus increases the cell’s oxidative imbalance, leading to cell damage if O₂⁻ is not rapidly dismutated to H₂O₂ and H₂O by superoxide dismutase (SOD). In turn, H₂O₂ is more stable than O₂⁻ and consequently is more toxic to cells over time. Therefore, H O must be removed as well by a collection of enzymes, such as ascorbate peroxidase (APX) and catalases (CAT). In this study, possible stress-signalling of MG in seedlings under normal conditions and Zr-stress were investigated to establish whether MG at a low dose (6 μM) would benefit seedling growth and development, via a proposed preinduction of the B. rapa L. antioxidant system. Therefore, it was proposed that ROS accumulation due to the exogenous application of MG, would incite the activation of antioxidants and thus mitigate the effects of Zr stress. Physiological tests to determine dry weights (figure 3.2.3) and germination percentage (figure 3.2.2) revealed that MG-treated seedlings yielded an improved biomass and early development compared to Zr-treated seedlings and the control. Membrane damage as assessed by lipid peroxidation viz. Malondialdehyde [MDA] (figure 3.2.4) and conjugated dienes [CD] (figure 3.2.5) also indicated less damage in MG-treated seedlings compared to the Zr-treated set. The chlorophyll content observed was prominent (table 3.1). MG-treated seedlings exhibited a 40% and 15.5% increase compared to Zr-treated seedlings and the control respectively. Moreover cell viability had improved in MG-treated seedlings compared to the control, and in MG+Zr-treated seedlings only a slight increase in cell death occurred despite Zr being present. O₂⁻, H₂O₂ and •OH (figure 4.2.1 – 4.2.3) were investigated in B. rapa L. seedlings in response to Zr and MG by spectrophotometric biochemical assays, as well as their scavenging enzymes, MG accumulation and Gly-I activity. Furthermore, BrGLY1 gene expression and Zr-uptake by ICP-OES were performed. Seedlings treated with MG and Zr respectively showed an increase in ROS. However, all of the ROS observed in MG+Zr-treated seedlings were markedly lower compared to Zr-treated seedlings. SOD and CAT activity observed in MG+Zr-treated seedlings had decreased compared to Zr-treated seedlings, whereas APX activity had increased. Gly-I activity and BrGlyI gene expression had increased across all treatments, showing an elicited response to oxidative stress, due to the observed upregulation, as a result of the accumulated MG. The observed Zr-uptake in MG+Zr-treated seedlings was inhibited by 5-fold compared to Zr-treated seedlings. Clear signs of stress were evident in seedlings treated with Zr compared to the control and MG- treated seedlings, the MG-supplemented (MG and MG+Zr) seedlings displayed a vast improvement comparatively. Modulation of antioxidant activity observed in this study is indicative of an incited response to oxidative stress (figure 4.2.4 – 4.2.6). MG revealed distinct involvement in stress-signalling, ROS levels had increased, although not as severely as with Zr-treated seedlings, but seemingly enough to activate antioxidants without eliciting damage. Furthermore, the proposed early-onset activation of antioxidants has been observed in B. rapa L. seedlings of this study, and as such has resulted in improved growth, development and seed germination. The results of this study has therefore negated the previous reports on MG-toxicity (at high concentrations), and has shed light on further properties of this ubiquitous and inevitably-occurring metabolite at low levels.
National Research Foundation (NRF)

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Dewan, Dilruba Begum. "Field performance of Brassica rapa L. doubled haploid lines and hybrids in Saskatchewan". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1996. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/nq24070.pdf.

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Cutts, Todd Andrew. "Herbicide resistance enriched hybrid and synthetic seed production and performance in Brassica rapa". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp03/MQ51700.pdf.

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Smetanska, Iryna. "Impact of elicitors on glucosinolate production in plants and exudates of turnip (Brassica rapa)". [S.l.] : [s.n.], 2005. http://deposit.ddb.de/cgi-bin/dokserv?idn=979353963.

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Wang, Qiang. "Chronic Impact Of Cerium Oxide Nanoparticles On Solanum Lycopersicum L. And Brassica Rapa L". OpenSIUC, 2014. https://opensiuc.lib.siu.edu/dissertations/896.

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Cerium Oxide Nanoparticles (CeO2-NPs) are commonly used in polishing, engine enhancement agents and many other commercial products. Increased applications and accidental release have raised concerns on the potential impact of CeO2-NPs on the environment. Most previous studies focused on the short term effect of CeO2-NPs. Information is severely lacking on the long-term impact of CeO2-NPs at environmentally relevant concentrations. The main goal of the current dissertation was to investigate the chronic phytotoxicity of CeO2-NPs on two plant species, tomato (Solanum lycopersicum L.) and Turnip mustard (Brassica rapa L.) fast growing variety, and the physiological and biochemical responses of these two plant species to CeO2-NPs. Four specific objectives were established. The first objective was to investigate the effects of combined CeO2-NPs and TiO2-NPs exposure on tomato plant growth and oxidative stress. The second objective was to investigate the impact of a lifecycle exposure to CeO2-NPs on wild type tomato growth and fruit yield and to evaluate the transgenerational effects of CeO2-NPs exposure on plant growth and the oxidative stress of the second generation tomato seedlings. The third objective was to compare the influence of CeO2-NPs and bulk CeO2 particles on plant growth and oxidative stress of standard fast growing Brassica rapa. The final objective was to evaluate the risks of CeO2-NPs exposure over three generations on Brassica plant growth, oxidative stress and reproduction. The results suggested that firstly, CeO2-NPs pre-exposure at concentrations of 4 and 40 mg/kg dry soil followed by 1000 mg/L of TiO2-NPs post-treatment increased H2O2 content and antioxidant proteins activities compared with CeO2-NPs alone and TiO2-NPs alone, and reduced biomass of the tomato plants compared with CeO2-NPs alone. Secondly, irrigation of CeO2-NPs at concentrations up to 10 mg/L stimulated wild type tomato plant growth, but exposure to CeO2-NPs over a lifecycle harmed plant growth and induced higher H2O2 content in tomato seedlings of the second generation. Thirdly, bulk CeO2 exposure at irrigation concentrations of 10, and 100 mg/L were more beneficial for Brassica rapa plant growth than CeO2-NPs at equivalent concentrations. CeO2-NPs irrigation at 10 and 100 mg/L increased H2O2 content and antioxidant proteins activities than bulk CeO2 at equivalent concentrations. However, the mustard plants treated by CeO2-NPs or bulk CeO2 showed changes of H2O2 content in different growth stages, which illustrated that CeO2-NPs and the bulk counterpart induced the change of H2O2 content differently. Finally, irrigating mustard plants with 10 to 1000 mg/L CeO2-NPs over three generations resulted in an inhibited plant growth, stronger oxidative stress, less seed yield and poorer reproduction of offspring plants. To our knowledge, this is the first report on the chronic (multigenerational) effects of CeO2-NPs on plant growth and oxidative stress of tomato and mustard plants grown in soil.

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23

Greffier, Laurent. "Obtention et caractérisation d'autotétraploïdes chez trois espèces de brassica apparentées : B. Nigra (L) Koch, B. Rapa (L.) Et B. Juncea (L.) Czern". Dijon, 1994. http://www.theses.fr/1994DIJOS038.

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L'objectif de cette étude a consisté à obtenir et étudier des autotétraploïdes chez trois espèces de Brassica apparentés: B. Nigra (l. ) Koch, B. Rapa L, B. Juncea (l. ) Czern. Deux voies d'obtention ont été abordées: polyploïdisation somatique par traitement à la colchicine et polyploïdisation gamétophytique par l'intermédiaire de gamètes non réduits. La culture de bourgeons axillaires sur un milieu in vitro additionne de colchicine a permis d'obtenir des autotétraploïdes chez les trois espèces étudiées. Les autotétraploïdes se caractérisent par une augmentation de la masse des graines et de la teneur en sinigrine mais la fertilité est réduite. L'autotétraploïdie entraine une augmentation de la taille des grains de pollen et du nombre d'apertures. Cependant, le critère nombre d'apertures n'est pas suffisant pour détecter des diplogamètes mâles chez les plantes diploïdes. La réalisation, chez B. Nigra de croisements 4x avec 2x et 2x avec 4x permet d'obtenir des autotétraploïdes par l'intermédiaire de gamètes non réduits mâles ou femelles

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24

Thrash, Stephen Tyler. "The genetic architecture of resource allocation in Brassica rapa as a result of salt stress". Miami University / OhioLINK, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=miami1626945751785996.

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25

Kadir, Nawzad. "Plant mediated effects of earthworms on aphid dynamics". Thesis, University of Plymouth, 2014. http://hdl.handle.net/10026.1/3037.

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The individual and combined effects of the endogeic and epigeic groups of earthworms on the growth of Chinese cabbage (Brassica rapa), and on the subsequent growth and development of the generalist sap-sucking herbivore Myzus persicae were determined in separate pot experiments. Many previous studies have investigated the relationship between soil biodiversity and aboveground plants, but few researches have considered the indirect interaction between soil biota and above-ground aphids. In this study the individual effects of Aporrectodea rosea and Allolobophora chlorotica and the combined effects of A. rosea and A. chlorotica, Aporrectodea caliginosa and Satchellius mammalis, A. chlorotica and S. mammalis, and A. rosea, A. caliginosa, Lumbricus rubellus and S. mammalis on plant morphology and physiology and aphid development (nymphs day-1, fecundity and number of adults) were investigated. Plant growth was affected by the presence of A. rosea which caused increases in plant biomass, height of plant, leaf surface area and specific leaf area (SLA). Mean number of leaves per plant was unaffected by worm density. In contrast, increasing density of A. chlorotica had no effect on any aspect of plant performance. The combined effect of A. rosea and A. chlorotica resulted in a similar increase in plant biomass to A. rosea alone. While the combined effects of A. caliginosa and Satchellius mammalis, A. chlorotica and S. mammalis and A. rosea, A. caliginosa, L. rubellus and S. mammalis caused increases in all plant parameters except leaf number. Additionally, the individual effect of A. rosea and the combined effects of A. caliginosa and S. mammalis, A. chlorotica & S. mammalis and A. rosea and A. caliginosa, L. rubellus and S. mammalis resulted in increased in leaf nitrogen concentration. Aphid development was also affected by the presence of earthworms. The nymphs day-1, fecundity and numbers of adults were significantly increased with increases in earthworm densities. The interaction between all groups of earthworms and their influence on aphid growth showed that the combined effect of two different groups was greater than the individual groups. Proteomic techniques were used to compare protein patterns in the plants. The combined effects of A. caliginosa and S. mammalis, A. chlorotica and S. mammalis, A. rosea, A. caliginosa, L. rubellus and S. mammalis earthworms on plant resulted in differences in number and kind of protein between plant treated with earthworms and the control, but no significant difference in proteins volume. Effects of earthworms on plant growth and aphid development are shown to be modified by increasing density and interactions between different species and functional groups of earthworms.

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Muñoz, Castro Carolina Andrea. "Identidad y pureza varietal de nabina (Brassica rapa L. var. silvestris (Lam.) Briggs.) cultivar Carlinda". Tesis, Universidad de Chile, 2012. http://www.repositorio.uchile.cl/handle/2250/116078.

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Memoria para optar al Título Profesional de Ingeniero Agrónomo
No autorizada por el autor para ser publicada a texto completo
Con el objetivo de verificar un buen procedimiento en la producción de semilla, se realizó un post-control a la crucífera Nabina (Brassica rapa L. var. silvestris (Lam.) Briggs.) cultivar Carlinda producida en Francia. Basando la evaluación en las directrices de la UPOV (Unión Internacional Para la Protección de las Obtenciones Vegetales) (TG/185/3) y los estados de desarrollo de Berkenkamp, se realizó una caracterización y comparación con una muestra estándar proporcionada por el obtentor para verificar el cultivar de la semilla producida y establecer la pureza varietal de ésta. Para los caracteres cualitativos evaluados mediante el protocolo UPOV, se utilizó la nomenclatura de notas y para los cuantitativos, se utilizaron las unidades métricas determinadas en cada planta. En total se analizaron 19 caracteres. Se realizó una prueba t de Student para encontrar diferencias significativas entre las dos muestras analizadas y un Análisis de Componentes Principales (ACP) para identificar los factores de mayor relevancia en la posible variabilidad de los datos. Las evaluaciones mostraron una contaminación de un 2,5% en la muestra producida en Francia, contaminación que sobrepasa la tolerancia admitida para ser exportada; el producto se diferencia categóricamente en 6 caracteres, los que son: curvatura de la punta de la hoja, tipo de hoja, número de lóbulos de la hoja, ondulación del borde de la hoja, producción de polen y largo de la silicua.

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27

Nellist, Charlotte F. "The deployment and mechanism of broad-spectrum resistance to turnip mosaic virus in Brassica rapa". Thesis, University of Warwick, 2013. http://wrap.warwick.ac.uk/62029/.

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The potyvirus Turnip mosaic virus (TuMV) is a major constraint on the cultivation of a wide range of plant species worldwide. It causes significant economic losses in brassica species such as Chinese cabbage (Brassica rapa), which is one the most important vegetable crops in the world. The B. rapa line RLR22 has broad-spectrum resistance to TuMV, which is undefeated. Many recessive resistances against plant viruses in the Potyvirus genus are based on mutations in plant eukaryotic translation initiation factor 4E (eIF4E), or its isoform eIF(iso)4E . B. rapa has three eIF4E genes and three eIF(iso)4E genes. Segregation following a cross between RLR22 and the TuMV-susceptible R-o-18 line of the closely related B. rapa ssp. trilocularis revealed the resistance was due to a recessive gene, retr01 that was epistatic to a dominant gene, ConTR01. My research revealed that retr01 is BraA.eIF(iso)4E.a and that ConTR01 is probably BraA.eIF(iso)4E.c. It also showed that the highly sought after broad-spectrum resistance to TuMV is due to a novel, recessive, natural mechanism, based on the mis-splicing of BraA.eIF(iso)4E.a in B. rapa. This results in a range of eIF(iso)4E splice variants, the most common of which retained the whole of intron 1 and appears to be non-functional for the virus. As the susceptible parent in the original cross, R-o-18, was a different sub-species to RLR22 (B. rapa var. pekinensis, Chinese cabbage), the genetic inheritance of resistance was also investigated in crosses with Chinese cabbage lines; F2 segregation ratios were consistent with those predicted for the single recessive gene (retr01 ). Yeast two-hybrid interactions between the viral protein genome-linked (VPg) of TuMV and eIF(iso)4E from B. rapa seem to be TuMV isolate-specific. Aphid transmission experiments to investigate the complementation of an eIF(iso)4E Arabidopsis thaliana knockout line with B. rapa BraA.eIF(iso)4E.a confirmed the earlier results from mechanical inoculation of these plants. The inability of TuMV to access multiple copies of eIF(iso)4E in Chinese cabbage and the broad-spectrum of the resistance, suggest it may prove to be durable.

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28

Elam, Robert J. "The Effects of Coal Dust Particulates on Growth Performance and Photomorphogenic Responses of Brassica Rapa". University of Cincinnati / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1511869210184817.

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Svetlana, Bošković. "Fitohemijski sastav, lekoviti potencijal i senzorne karakteristike sorti vrsta Brassica oleracea L. i Brassica rapa L. (Brassicaceae) iz organskog i konvencionalnog sistema proizvodnje". Phd thesis, Univerzitet u Novom Sadu, Prirodno-matematički fakultet u Novom Sadu, 2016. https://www.cris.uns.ac.rs/record.jsf?recordId=101645&source=NDLTD&language=en.

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U ovom radu su ispitani hemijski sastav i biološka aktivnost vrsta Brassica oleracea i Brassica rapa poreklom iz organskog i konvencionalnog sistema proizvodnje. Ispitivanja hemijskog sastava su obuhvatila određivanje volatilnih komponenata primenom headspace GC-MS tehnike, kvalitativnu analizu sokova ispitivanih vrsta pomoću LC-DAD-MS/MS tehnike, kvantifikaciju odabranih fenolnih jedinjenja pomoću LC-MS/MS tehnike i spektrofotometrijsko određivanje sadržaja ukupnih glukozinolata, fenola i flavonoida i sadržaja ukupnih monomernih antocijana. Biološka aktivnost povrća je ispitana određivanjem antioksidantnog potencijal, antimikrobne i antitumorske aktivnosti sokova. Dobijeni rezultati pokazuju da su glavne volatilne komponente ispitivanih vrsta degradacioni proizvodi masnih kiselina i organosumpornih jedinjenja od kojih neke od identifikovanih komponenata predstavljaju ključne mirisne komponente. Na osnovu njihove distribucije nije bilo moguće utvrditi uticaj sistema proizvodnje na miris i ukus ispitivanih vrsta. Pomoću LC-DAD-MS/MS i LC-MS/MS tehnike je utvrđeno prisustvo primarnih metabolita, slobodnih hidroksibenzoevih i hidroksicimetnih kiselina, derivate hinske kiseline sa hidroksicimetnim kiselinama, glikozida flavonola, biflavonoida, i kumarina u sokovima spitivanih vrsta. Pored toga u svim sokovima subili prisutni kondenzacioni proizvodi degradacionih proizvoda indolnih glukozinolata sa askorbinskom kiselinom- askorbigen i metoksiaskorbigen. U sokovima crvenog kupusa su bili prisutni antocijani. Najveći sadržaj ukupnih glukozinolata je određen u brokoliju, dok je crveni kupus sadržao najveći sadržaj ukupnih fenola ukupnih flavonoida kao i hinske kiseline. Crveni kupus je bio varijetet koji je ispoljio najviši antioksidantni kapacitet u svim primenjenim testovima, brokoli i karfiol su ispoljili najjaču antimikrobnu aktivnost, dok je kelj bio varijetet sa najjačim antitumorskim delovanjem. Na osnovu analize hemijskog sastava i biološke aktivnosti vrsta B. oleracea i B. rapa može se zaključiti da u zavisnosti od primenjenog tipa proizvodnje mogu biti poboljšane neke od karakteristika ispitivanih vrsta i da je uticaj sistema proizvodnje značajan za pojedine varijetete, a nikako za celu vrstu. U konačnom obliku može se zaključiti da bi potencijalna kombinacija sokova crvenog kupusa, brokolija, karfiola i kelja mogla ostvariti značajno hemopreventivno i hemoterapeutsko delovanje, ispoljavajući istovremeno antioksidantnu, antimikrobnu i antitumorsku aktivnost.
Chemical composition and biological activity of Brassica oleracea and B. rapa species were investigated in the present work. Investigation of chemical composition encompassed determination of volatile compounds by headspace GC-MS technique, qualitative analysis of juices of investigated vegetables by LC-DAD-MS/MS technique, quantification of selected phenolic compounds by LC-MS/MS technique and spectrophotometric determination of total content of glucosinolates, phenolic compounds and flavonoids and total content of monomeric anthocyanes. Biological activity of vegetables was investigated by determination of antioxidant capacity, antimicrobial and antitumorigenic effect of juices. Obtained results showed that main volatile compounds were degradation products of fatty acids and organo-sulphur compounds among which some of the identified components were the key aroma compounds. Based on their distribution it was not possible to evaluate influence of cropping system on aroma and taste of investigated species. By LC-DAD-MS/MS and LC-MS/MS techniques, it was determined the presence of primary metabolites, freehydroxybenzoic and hydroxycinnamic acids, derivatives of quinic acid and hidroxicinnamic acids, flavonol glucosides, biflavnoids and a cumarin in juices of the investigated species. Furthermore, condensation products of degradation products of indole glucosinolates with ascorbic acid- ascorbigen and metoxiascorbigen were present in all juices. Anthocyanes were present in juices of red cabbage. The highest total content of glucosinolates was determined in broccoli, while red cabbage had the highest total phenolic content, total flavonoid content, as well as content of qunic acid. Red cabbage was a variety that showed the highest antioxidant capacity measured by different assays. Broccoli and cauliflower expressed the highest antimicrobial potential, while Savoy cabbage was a variety with the highest antitumor effect. Investigation of chemical composition and biological activity showed that applied cropping conditions may be useful for improving some of the characteristics of investigated species and significance of cropping system only for particular varieties, but not for the whole species in general. As the conclusion, potential combination of juices of red cabbage, broccoli, cauliflower and Savoy cabbage could be potent chemopreventive and chemotherapeutic agent, expressing simultaneously antioxidant, antimicrobial and antitumor activity.

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30

Van, Averbeke W., KA Juma i TE Tshikalange. "Yield response of African leafy vegetables to nitrogen, phosphorus and potassium: The case of Brassica rapa L. subsp. chinensis and Solanum retroflexum Dun". Water SA, 2007. http://encore.tut.ac.za/iii/cpro/DigitalItemViewPage.external?sp=1000786.

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In this study the growth and yield response of Solanum retroflexum Dun. (nightshade) and Brassica rapa L. subsp. chinensis (non-heading Chinese cabbage) to N, P and K availability in the soil and the interaction effects of these three nutrients were determined by means of pot experiments in a greenhouse. S. retroflexum was most sensitive to the availability of nitrogen in the soil. Sufficient nitrogen needed to be available to achieve optimum growth but adding too much adversely affected biomass production, suggesting a fairly narrow optimum range for nitrogen availability. The production of the crop was also dependent on the adequate availability of phosphorus and potassium but any adverse effects due to excess availability were less distinct than for nitrogen. In the case of B. rapa subsp. chinensis, an optimum availability range was identified for N and K and a critical level of availability for P. The decline in biomass production caused by adding N in excess of the optimum was reversed by applying both P and K at rates that were in excess of the respective optima.

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31

Ren, Chengwei. "Characteristics and physiological causes of a precocious germination mutant of Chinese cabbage (Brassica rapa ssp. Pekinensis)". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp03/NQ27466.pdf.

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32

Collins, R. P. "The role of calcium and potassium in salinity tolerance in Brassica rapa L. cv. RCBr seed". Thesis, Coventry University, 2012. http://curve.coventry.ac.uk/open/items/e0d653ff-7d6b-4827-9467-dc8bcb6ff621/1.

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The possibility of manipulating calcium (Ca2+) and potassium (K+) levels in seeds of Brassica rapa by altering parent plant nutrition and investigating the potential for increased salinity tolerance during germination, given that considerable amounts of literature imply that greater amounts of available exogenous Ca2+ and K+ can ameliorate the effects of salinity on both whole plant growth and germination, was evaluated. The investigation consisted of four growth trials. Two preliminary growth trials suggested that seed ion manipulation was possible without affecting the overall growth and vigour of the plant. After developing suitable high and low Ca2+ and K+ nutrient solutions for growth, a trial was carried out in a growth room and greenhouse, with various substrates and the seed of a certain size category was collected for subsequent ion and salinity tolerance analysis. Seed Ca2+ and K+ was significantly affected by growth substrate and nutrient solution and data showed that a significant negative regression relationship existed between seed Ca2+, K+ and Ca2+ + K+ levels and salinity tolerance. Further experimentation using hydroponic culture attempted to remove any possible effects of substrate and also to compare size categories of seed with a view to elucidating localisation of Ca2+ and K+. Seed Ca2+ was found to be significantly altered by nutrient solution in the two different sizes tested and higher Ca2+ nutrient solution was found to increase salinity tolerance in daughter seed. One significant negative regression correlation between salinity tolerance and seed K+ concentration existed in smaller seed, but disregarding seed size in a regression analysis of seed ion content and salinity tolerance, a significant negative relationship existed between seed Ca2+, K+ and Ca2++ K+. The results, especially in terms of Ca2+ nutrition, contradict much previous research that suggests increased salinity tolerance at germination can arise with the increased presence of Ca2+ and/or K+. Salinity tolerance was greater in seeds of larger size across all nutritional treatments and the smaller size range exhibited increased Ca2+ and K+ per μg seed. Ca2+ concentration in smaller seeds with greater surface area:volume ratios provided a clue to the potential localisation of Ca2+. Cross sectional staining showed that a greater proportion of seed Ca2+ may reside in the coat. This was confirmed by analysis which showed an approximate 50% split of total extractable seed Ca2+, regardless of size, between coat and embryo within a seed; the majority of which, per μg, resides in the coat. Further work looked at the relative solubility of the Ca2+ and K+ in these tissues and whole seed to look at the potential bioavailability of Ca2+ during germination from various parts of the seed. Most water soluble Ca2+ exists in the embryo and most insoluble Ca2+ exists in the coat, but coat Ca2+ was found to be ionically exchangeable and therefore bioavailable. K+ appeared mostly water soluble in embryo and coat. In line with previous whole plant research in this species, most Ca2+ is readily water soluble or ionically exchangeable in form and the possible negative effects of how increasing bioavailable Ca2+ may reduce salinity tolerance was discussed.

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33

Sarkissian, Taline S. "The evolutionary genetics and adaptive significance of intraspecific variation in pollen grain size in Brassica rapa L". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp01/MQ48038.pdf.

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34

Barrow, Wendy Elizabeth Richings. "The effects of defoliation by Plutella xylostella Lon, the growth and the yield of Brassica rapa L". Thesis, Imperial College London, 1986. http://hdl.handle.net/10044/1/37936.

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35

Hill, Donna. "Isolation & Characterization of DNA Polymerase Alpha and Gamma from Turnips (Brassica rapa) and Etiolated Soybeans (Glycine max)". TopSCHOLAR®, 1988. https://digitalcommons.wku.edu/theses/2483.

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DNA polymerase alpha, the enzyme involved in nuclear DMA replication, and DNA polymerase gamma, the enzyme involved in organellular DNA replication, were isolated and purified from soybean and turnip. The enzymes were characterized following ammonium sulfate precipitation, DEAF-cellulcse, phosphocelluloca, and hydroxylapatite chromatography, and by non-denaturing polyacrylamide gel electrophoresis. Protein banct were electropluted and the enzymes characterized using kinetic studies and sensitivity to divalent cations and inhibitors. Molecular weight and subunit composition studies indicated a molecular weight for the catalytic subunit of DNA polymerase alpha in soybean and turnip to be 46kDa. DNA polymeraqe gamma was composed of a catalytic subunit with a molecular weight of 66kDa. Although the two enzymes appear to share common subunits, characterization of their genetic origin remains to be determined before alpha and gamma can be classified as isoenzymes.

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36

O'Keefe, David John. "Differential Expression of Isopentenyl Transferase and Cytokinin Oxidase/Dehydrogenase During Pod and Seed Development in Brassica". Thesis, University of Canterbury. Biological Sciences, 2012. http://hdl.handle.net/10092/7040.

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Consistency of yield and quality of seed are traits not yet optimised by the brassica seed industry in New Zealand. As of 2008, seed producers in Canterbury, New Zealand, exported approximately $18m of brassica seed. However, there is a need to increase both seed quantity and/or quality. The plant hormone group, the cytokinins, regulates many stages of plant growth and development, including cell division and enhancement of sink strength, both of which are important processes in seed development and embryonic growth. The two gene families targeted in this project play a key role in maintaining cytokinin homeostasis. Isopentenyl transferase (IPT) catalyzes the rate limiting step in the formation of cytokinins, and cytokinin oxidase/dehydrogenase (CKX) irreversibly inactivates cytokinins. The aim of this project was to identify those cytokinin gene family members expressing specifically during the early phases of pod and seed development. Initially this study used a rapid-cycling Brassica rapa (RCBr) because of its rapid life cycle, then, as the project developed, a commercial crop of forage brassica (B. napus) was studied. Reverse transcriptase PCR (RT-PCR) and BLAST analysis was used to identify putative IPT and CKX genes from RCBr and B. napus. Quantitative reverse transcriptase polymerase chain reaction (qRT-PCR) was used to measure the expression of individual gene family members during leaf, flower, pod and seed development. BrIPT1, -3, and -5, and BrCKX1, -2, -3, and -5/7 and were shown to express differentially both temporally and spatially within RCBr root, stem, leaf, seed, and pod tissues. BnIPT1, 3 and 7 and BnCKX1, 2, 5 and 7 were also differentially expressed. Particularly strong expression was shown by BrIPT3, BrIPT5 and BrCKX2 in developing seeds. Both Brand BnIPT3 expressed strongly in maturing leaves. In normal plant growth and development, biosynthesis and metabolism of cytokinin is tightly regulated by the plant. Increasing the levels of cytokinins during seed development, either by over expressing IPT3 or IPT5, or decreasing the expression of CKX2, or both, could potentially increase both seed yield and seed vigour.

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Van, Averbeke W., Tshikalangem TE i KA Juma. "The commodity systems of Brassica rapa L. subsp. chinensis and Solanum retroflexum Dun. in Vhembe, Limpopo Province, South Africa". Water SA, 2007. http://encore.tut.ac.za/iii/cpro/DigitalItemViewPage.external?sp=1000785.

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Using farmer surveys the smallholder commodity systems of Brassica rapa L. subsp. chinensis and Solanum retroflexum Dun. in Vhembe District, Limpopo Province, South Africa were described and analysed. Production, transaction and consumption of the two vegetables were deeply embedded in the food, trade and farming systems of local people. The cultivation systems, which appeared effective, were developed by borrowing elements from the systems of other crops to which new knowledge specific to B. chinensis and S. retroflexum were added. Several elements of the production systems that could benefit from scientific enquiry were identified. These included genetic improvement and the optimisation of planting density and nutrient supply.

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Kolkailah, Naiyerah F. "Genes Encoding Flower- and Root-Specific Functions are More Resistant to Fractionation than Globally Expressed Genes in Brassica rapa". DigitalCommons@CalPoly, 2016. https://digitalcommons.calpoly.edu/theses/1586.

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Like many angiosperms, Brassica rapa underwent several rounds of whole genome duplication during its evolutionary history. Brassica rapa is particularly valuable for studying genome evolution because it also experienced whole genome triplication shortly after it diverged from the common ancestor it shares with Arabidopsis thaliana about 17-20 million years ago. While many B. rapa genes appear resistant to paralog retention, close to 50% of B. rapa genes have retained multiple, paralogous loci for millions of years and appear to be multi-copy tolerant. Based on previous studies, gene function may contribute to the selective pressure driving certain genes back to singleton status. It is suspected that other factors, such as gene expression patterns, also play a role in determining the fate of genes following whole genome triplication. Published RNA-seq data was used to determine if gene expression patterns influence the retention of extra gene copies. It is hypothesized that retention of genes in duplicate and triplicate is more likely if those genes are expressed in a tissue-specific manner, as opposed to being expressed globally across all tissues. This study shows that genes expressed specifically in flowers and roots in B. rapa are more resistant to fractionation than globally expressed genes following whole genome triplication. In particular, there appears to have been selection on genes expressed specifically in flower tissues to retain higher copy numbers and for all three copies to exhibit the same flower-specific expression pattern. Future research to determine if these observations in Brassica rapa are consistent with other angiosperms that have undergone recent whole genome duplication would confirm that retention of flower-specific-expressed genes is a general feature in plant genome evolution and not specific to B. rapa.

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Leonardo, Tiago Miguel Santos. "Study of Brassica rapa core collection for morphological traits, self-incompatibility, interspecific hybridization and Xanthomonas campestris PV. campestris disease resistance". Master's thesis, ISA, 2013. http://hdl.handle.net/10400.5/6113.

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Mestrado em Engenharia Agronómica - Instituto Superior de Agronomia
Rijk Zwaan Brassica rapa Gene Bank Collection, comprising 137 accessions representing different morphortypes, was studied and evaluated for morphological traits and self incompatibility, interspecific hybridization and Xanthomonas campestris pv. campestris disease resistance. In order to distinguish different morphotypes, leaf and seed pod traits were measured and analized. Only the leaf traits contribute to distinguish between the morphotypes. Recurring to open flowers pollination, self incompatibility was scored through two different methods: assessment of pollen ingrowth and seed counting. Through the assessment of pollen tube ingrowth was concluded that the majority of accessions are self incompatible or moderately self incompatible. Although seed counting does not agree with these results. Success rate of natural interspecific hybridization with Brassica oleracea was accessed through pollination of immature flower buds. Direct and reciprocal pollinations were performed but only the direct pollinations were scored. After counting the seeds it was concluded that success rate was very low. There was no significant correlation between the seed set and plant morphotypes. A screening for resistance against two races (1 and 4) of Xanthomonas campestris pv. campestris was performed. Resistant plants were found for both races. Significant differences in resistance were found for the two races and between morphotypes. Chromossome counting was performed for one accession resistant to both races. After counting it was concluded that it is an allotetraploid, either Brassica carinata (BC) or Brassica juncea (AB), in agreement with the literature, which refers B genome as a resistant. This work was useful to identify the presence of resistance to Xanthomonas campestris pv. campestris race 4 in Brassica rapa. Further work has to be performed to study the nature of the resistance and a larger number of Brassica rapa accessions can still be screened for resistance to Xanthomonas campestris pv. campestris race 1.

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Moreira, Inês Neto. "Mecanismos antioxidantes de resposta ao stresse induzido por metais tóxicos em nabiças". Master's thesis, ISA/UTL, 2011. http://hdl.handle.net/10400.5/4480.

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Herrera, Díaz Areli [Verfasser], i Hans-Ulrich [Akademischer Betreuer] Koop. "Regeneration and plastid transformation approaches in Arabidopsis thaliana and Rapid-Cycling Brassica rapa / Areli Herrera Díaz. Betreuer: Hans-Ulrich Koop". München : Universitätsbibliothek der Ludwig-Maximilians-Universität, 2011. http://d-nb.info/1015500803/34.

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Adu, Michael Osei. "Variations in root system architecture and root growth dynamics of Brassica rapa genotypes using a new scanner-based phenotyping system". Thesis, University of Nottingham, 2014. http://eprints.nottingham.ac.uk/14259/.

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There is a need to breed for root systems architectures (RSAs) that optimise soil resource acquisition. This requires high resolution and high-throughput quantification of RSA in as natural an environment as possible. Current imaging techniques are limited by cost, reproducibility, throughput and complexity. This thesis describes (1) the construction of a low cost, high-resolution, root phenotyping platform that requires no sophisticated equipment which is adaptable to most laboratory and glasshouse environments and (2) its application to quantify environmental and temporal variation in RSA between genotypes of Brassica rapa L. The high resolution root phenotyping system (HRP) that was constructed employed 24 scanners and could screen up to 72 individual plants at any time, with the possibility of capturing thousands of root images daily depending on the operational number of scanners and scanning periodicity. Plants were supplied with a complete nutrient solution through the wick of a germination paper. Images of RSA were acquired automatically, over extended periods, using multiple scanners controlled by customised software. The RSA data was used to validate a mechanistic model and mixed effects models were used to describe the sources of variation in traits contributing to RSA. Plants were also grown in rhizoboxes and under varying concentrations of P ([P]ext). Broad-sense heritability (H2), was highest (≥ 0.70) for shoot biomass, length of primary roots (PRs), number of lateral roots (LRs). Coefficients of variation in RSA traits within a genotype were large and ranged between 5 and 103%. It was found that between 4 and 48 replicates were needed to detect a significant difference (95% CI, 50% difference between trait means). Significant differences were found between genotypes in root traits with strong positive correlations among RSA traits and between biomass and RSA traits. Principal component analyses identified 5 significant axes of variation, accounting for approximately 86 and 78% of the variation in the genotypes on paper and soil substrates, respectively. Cluster analysis of the genotypes produced 5 discrete groups. Genotypes with more or less shoot biomass or with bigger or smaller RSA could be distinguished. A density-based 2D model reproduced experimental results accurately by simulating PR length and total length of LRs. Mixed-effects statistical models demonstrated that root traits show temporal variations of various types with significant effects of genotype. All genotypes followed a similar growth pattern with time, but differed in their maximum total root length (TRL), primary root length (PRL) and LR growth. A 3-parameter logistic model satisfactorily described TRL and PRL when genotypes were grown on both paper and soil substrates. On paper substrate, TRL required only a single, random-effect parameter (asymptote), describing maximum TRL. On soil substrate, TRL required two random-effects parameters, asymptote and inflection, describing maximum TRL and time at which ½ of maximum TRL occurs, respectively. Primary root length on both paper and soil substrates required only a single, random-effect parameter, describing maximum PRL. The growth rate of LRs of all ages followed a quadratic function and required only a single, random-effect parameter, describing maximum growth rate. There was variation in specific RSA traits and plasticity in response to [P]ext among genotypes. Length of the apical un-branched zone of the PR increased with increasing [P]ext. Total root length, total LR length and number of LRs was positively correlated with total plant tissue P concentration at low [P]ext but not at high [P]ext. Paper substrate was more suitable for screening seedling root traits but root phenotypes must be validated in situ in the field or in soil media because some differences were evident between data observed on paper and soil substrates. Scanner-based phenotyping of RSA provides economical means of studying the mechanisms underlying the plant-soil interactions and can be used to quantify environmental and temporal variation in traits contributing to RSA. The HRP system can be extended to screen the large populations required for breeding for efficient resource acquisition. The necessity for high replication and time-consuming image analysis could however limit throughput in the phenotyping system.

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Ludwig, Tobias. "Regulierung von Rapsschädlingen im ökologischen Winterrapsanbau durch den Mischanbau mit Rübsen (Brassica rapa L. var. silvestris (Lam.) Briggs) sowie den Einsatz naturstofflicher Pflanzenschutzmittel". Doctoral thesis, Humboldt-Universität zu Berlin, Landwirtschaftlich-Gärtnerische Fakultät, 2013. http://dx.doi.org/10.18452/16759.

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An drei Standorten wurde die schädlingsregulierende Wirkung einer Raps-Rübsen-Mischsaat (Verhältnis 9:1) gegenüber einer Raps-Reinsaat bewertet. Des Weiteren wurden naturstoffliche und nach § 6a PflSchG selbst hergestellte Pflanzenschutzmittel als auch eine Käfersammelmaschine zur Regulierung der Stängelrüssler (Ceutorhynchus spp.) und des Rapsglanzkäfers (Meligethes aeneus F.) in Labor- und Freilandversuchen angewandt. In der Mischsaat war die Schaderregerabundanz gegenüber der Reinsaat zumeist erhöht. Diese führte zu einem teils signifikant stärkeren Schaderregerbefall der Rapspflanzen in der Mischsaat. Die Mischsaat erbrachte zudem einen teils signifikant geringeren Kornertrag. Natur-Pyrethrum und Spinosad führten im Labor zu deutlich erhöhten Mortalitäten bei den Stängelrüsslern. Im Freiland war kein Effekt erkennbar. Bei der Regulierung der Rapsglanzkäfer wies Spinosad in Feld- und Laborversuchen Wirkungsgrade bis zu 100 % auf. Gespritztes Gesteinsmehl und SiO2 zeigten einen nur geringen Effekt. Für die gleichmäßige Benetzung der Pflanzen mit diesen Präparaten kommt der Formulierung der Pflanzenschutzbrühe und der wiederholten Applikation eine hohe Bedeutung zu. Ökonomisch sind mehrfache Applikationen jedoch abzulehnen. Gestäubtes Gesteinsmehl und die Käfersammelmaschine sind aus Praktikabilitätsgründen nicht geeignet zur Regulierung der Rapsglanzkäfer. Ebenso wenig geeignet sind Quassin, Azadirachtin oder ein Bacillus thuringiensis-Präparat (B.t.t.). Mit Ausnahme einer Spinosad Applikation erzielte keine Pflanzenschutzmaßnahme einen wirtschaftlichen Mehrertrag. Stickstoffmangel und Unkrautkonkurrenz scheinen im ökologischen Rapsanbau häufig stärker auf die Limitierung der Kornerträge zu wirken als ein leichter bis mittlerer Schädlingsbefall. Je besser die Nährstoffversorgung und je geringer die Unkrautkonkurrenz, desto eher kann durch Pflanzenschutz ein wirtschaftlicher Mehrertrag realisiert werden. Die nötigen Pflanzenschutzkonzepte fehlen jedoch weiterhin.
On three sites the pest-regulating effect of a rape-turnip rape mixed cropping system (ratio 9:1) in comparison to rape in pure stand was assessed. Further, natural and self-produced natural insecticide solutions (§ 6a Plant Protection Act) and a beetle collecting machine to regulate the stem weevils (Ceutorhynchus spp.) and the pollen beetles (Meligethes aeneus F.) were applied in laboratory and field experiments. Compared to the fields in pure stand the mixed crop showed a significantly greater abundance of pests. This resulted in a sometimes significantly greater pest infestation of the rape plants in the mixed crop. Furthermore, the mixed crop often had a significantly lower grain yield. The use of natural pyrethrum and Spinosad resulted in significantly higher mortality rates of the stem weevils in laboratory tests. Under field conditions no effect could be detected. In the regulation of the pollen beetles, Spinosad demonstrated under field and laboratory conditions efficiencies of up to 100 %. Sprayed mineral powder or SiO2 had only a slight effect. For a uniform wetting of the plants with these compounds the formulation of the phytosanitary broth and its repeated application are important factors. From an economic perspective, however, repeated applications are inefficient. For reasons of practicality rock-dusted flour and the beetle-collecting machine are not suitable for pollen beetle regulation. Quassin is just as inappropriate as Azadirachtin, or Bacillus thuringiensis (B.t.t.) for the regulation of the pollen beetle. With the exception of one Spinosad application, no protection measure provided an economic surplus. Nitrogen deficiency and weeds seem to more frequently limit grain yield than slight to moderate pest infestation levels. The better the nutrient supply and the lower the weed competition, the more likely by crop protection can be realized an economic surplus. Adequate crop protection strategies, however, have not yet been developed.

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Johnson, Wendy Ann. "Effects of light intensity and nitrogen source on pac choi (Brassica rapa l.), and interaction with the diamondback moth (Plutella xylostella l.)". Diss., Kansas State University, 2011. http://hdl.handle.net/2097/11981.

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Doctor of Philosophy
Department of Entomology
Raymond A. Cloyd
James R. Nechols
Raymond A. Cloyd
James R. Nechols
Greenhouse studies were conducted to examine direct effects of light intensity and nitrogen source on primary and secondary metabolism of pac choi (Brassica rapa L. var. chinensis cv. ‘Mei Qing Choi’) and indirect effects on diamondback moth (Plutella xylostella L.)(DBM). In the first study, plants were exposed to high and low light intensities during different times of the year, resulting in a range of light intensities. From four experiments, plants exhibited higher phenolic content, greater shoot biomass, and higher C:N ratios under high light intensity, whereas plants under low light intensity contained higher protein. Ferulic acid increased under high light intensity, and this increase was negatively correlated with male DBM body weights. However, DBM developed faster on plants in the August experiment (high light), compared to the July experiment (lower light). This implies that light intensity may not be affecting DBM through plant-mediated changes unless reduced male weights confer a reduction in larval consumption. In the nitrogen source study, application of an organic source of nitrogen (fish hydrolysate fertilizer) was compared to a conventional fertilizer to determine whether nitrogen source directly impacts pac choi chemistry and biomass, thus indirectly impacting DBM fitness. In two experiments, there was no significant effect of fertility treatment on pac choi nutrients or biomass, with the exception of percent leaf phosphorus, which was significantly higher in the conventional fertility treatment. For DBM, percent survival and cohort development were significantly reduced on pac choi receiving the organic fertilizer. Calcium and magnesium were significantly higher in pac choi infested with DBM larvae than plants without DBM. In addition, calcium was negatively correlated with female DBM body weights in one experiment for the organic treatment. Overall, this study demonstrated that pac choi plants that received the organic fertilizer were similar to pac choi plants that received a conventional fertilizer with the exception of phosphorus. Furthermore, female DBM body weights were negatively impacted by calcium in the organic treatment. As multiple fitness traits for DBM were negatively affected in the organic treatment, pac choi crops grown with fish hydrolysate fertilizer may experience less feeding from DBM.

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Leflon, Martine. "Effets de la structure de l’hybride et du fonds génétique sur le taux de recombinaison entre les génomes A de Brassica rapa (AA, 2n=20) et de B. Napus (AACC, 2n=38) : Application à l’introgression de gènes de résistance à Leptosphaeria maculans dans le colza". Rennes, Agrocampus, 2007. http://www.theses.fr/2007NSARC092.

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L’hybridation interspécifique entre espèces végétales apparentées constitue un bon moyen de réaliser des introgressions de gènes, en vue d’augmenter la variabilité génétique d’une espèce cultivée. Les recombinaisons génétiques entre les génomes des espèces croisées sont nécessaires pour optimiser les introgressions. Cette étude vise à définir les facteurs agissant sur les fréquences de recombinaison entre les génomes de l’espèce tétraploïde Brassica napus (colza, AACC, 2n=38) et de son progéniteur B. Rapa (AA, 2n=20) en se basant sur le cas de l’introgression de gènes de résistance à Leptosphaeria maculans dans le colza. Après avoir identifié trois gènes de résistance spécifique chez B. Rapa, j’ai testé les effets de trois faceurs sur les fréquences dans différents croisements. Je n’ai trouvé aucun effet de la divergence entre les génomes A de ces deux espèces, mais des effets significatifs du génotype colza et de la structure des hybrides F1. La structure de l’hybride F1 a un effet considérable : les hybrides triploïdes AAC, issus du croisement entre B. Napus et B. Rapa, réalisent à la méiose de 1. 8 à 3,4 fois plus de crossing-overs que les hybrides tétraploïdes (AACC), issus du croisement entre colza et colza synthétique (B. Rapa (AA) xB. Oleracea (CC)), et 6,1 fois plus de crossing-overs que l’espèce diploïde B. Rapa
Interspecific hybridization between plant related species is a good way to realise introgressino of genes, in order to increase the genetic variability of cultivated species. Genetic recombinations between genomes of the crossed species are needed to optimise introgressions. This study aims to determine the factors that act on recombination rates in crosses between the allotetraploid species B. Napus (AACC, 2n=38), and one of its progenitors, B. Rapa (AA, 2n=20), and is based on the study of introgression of resistance genes to Leptosphaeria maculans into B. Napus. After having identified three specific resistance genes in B. Rapa, I tested the effect of three factors on recombination rates between A genomes of B. Rapa and B. Napus, by the comparison of the rates obtained in different crosses. I detected no effect of the divergence between A genomes of B. Rapa and B. Napus, but significant effects of both the B. Napus genotype and the structure of F& hybrids. The effet of the hybrid structure was considerable : at the meiosis of AAC triploid hybnrids, resulting from crosses between B. Napus and B. Rapa, recombination rates were from 1. 8 to 3. 4 fold higher than in AACC tetrploid hybrids, resulting from crosses between B. Napus and a reysnthesized B. Napus (B. Rapa (AA) x B. Oleracea (CC)), and 6. 1 fold higher than in the diploid B. Rapa species

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Mesa, Laura A. "The influence of pollinator diversity and behaviour on pollen movement in Brassica rapa chinensis (Pak-Choi) crops, and its significance for gene escape". Thesis, University of Canterbury. School of Biological Sciences, 2008. http://hdl.handle.net/10092/2685.

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The overall aim of the study was to assess the risk of gene flow from Brassica crops by insectmediated pollen transport. I measured the viability of pollen in Brassica flowers throughout crop development and compared this with the viability of pollen transported by insects inside and outside one early- and one late-season crop. In order to evaluate the relative importance of different species in pollen transport, I measured abundance of flower visitors during crop development, and measured the foraging behaviour of five key pollinator species throughout the growing season, in relation to variation in microclimate, crop phenology and the relative abundance of other pollinator species competing for flower resources. Flower visiting insects of Brassica rapa crops were highly diverse, and their abundance and diversity changed with crop phenology. I found similar abundances at the family level for both crops studied, although capture rates were greater in the early- than in the late-season crop. Across flowering development, the greatest numbers of insects were captured at the peak of flowering for both crops. During the flowering period, Diptera was the most abundant order collected, followed by Hymenoptera. The most abundant family in Hymenoptera was Apidae which tracked crop development in both fields, with greater numbers of insects captured inside than outside the field. Standardized-count pollen loads were smaller in Diptera than in Hymenoptera. Of the five key pollinator species sampled, Lasioglossum sordidum (Hymenoptera: Halictidae), Apis mellifera (Hymenoptera: Apidae) and Bombus terrestris (Hymenoptera: Apidae) transported similar pollen loads, which were much greater than those carried by Eristalis tenax (Diptera: Syrphidae) and Melangyna novae-zealandiae (Diptera: Syrphidae). The numbers of insects captured outside of the crop were 10% and 33% of the totals captured inside for the early- and the late-season crop, respectively. The proportion of insects entering versus leaving the crop varied considerably across species, crops and trap location (i.e., whether traps were inside or 50 m outside the border of the crop). However, it is worth noting that not uncommonly more insects were attracted into the crop early in the season, staying there rather than leaving, and then when flowers started to disappear there was a massive escape of insects leaving. This research provides evidence for the influence of crop age on the foraging behaviour of key pollinators and for species-specific variation in the foraging behaviour of Brassica visitors with crop development. Temporal variation in the rate and variability of movement between flowers, and the duration and variability in time spent on each flower, throughout the growing season differed markedly between pollinator species. Flower density, plant density, and the abundance of other insects contributed to the observed variation in pollinator behavioural activity for A. mellifera, E. tenax, M. novae-zelandiae and L. sordidum. Bombus terrestris had the greatest rates and variability of movement, and the greatest rates of flower visitation among all key pollinators studied. Therefore B. terrestris might contribute to gene flow to a greater extent than other key pollinators. Additionally B. terrestris had the greatest variability in the rate of movement, increasing the risk of pollen movement over long distances. In summary, I found that (i) insect abundance and diversity changed with crop phenology and Diptera was the most abundant order collected, (ii) flower density, plant density, and the abundance of other insect pollinators were important factors explaining pollinator behaviour for all key pollinators, except B. terrestris, (iii) B. terrestris might contribute to gene flow to a greater extent than other key pollinators, because it has a greater rate of flower visitation and a greater flight distance between flowers than other pollinators, and (iv) pollen viability tended to decrease with crop development and declined sharply even just 50 m outside the edge of the crop.

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Soares, Cristina Isabel Moniz Torres. "Análise das potencialidades dos processos de transformação e valorização de resíduos verdes. Avaliação da fitotoxicidade do composto proveniente da compostagem de resíduos verdes na Ilha de São Miguel (Açores)". Master's thesis, ISA, 2019. http://hdl.handle.net/10400.5/21273.

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Mestrado em Engenharia do Ambiente / Instituto Superior de Agronomia. Universidade de Lisboa
A temática desta dissertação está diretamente ligada à valorização e gestão de resíduos verdes com vista à introdução de uma economia circular, de modo a contribuir para a mudança do paradigma atual de muitas sociedades que ainda seguem um modelo económico linear. Tal facto tem contribuído para a acumulação de resíduos em aterro e para o decréscimo da autossustentabilidade do planeta. Neste trabalho, a valorização dos resíduos verdes (resíduos provenientes de podas e desflorestação, tal como folhas, galhos e semelhantes) está presente na matéria fertilizante utilizada durante o ensaio laboratorial, o SO-MUSAMI, composto orgânico proveniente da compostagem de resíduos verdes produzido no Ecoparque da Ilha de São Miguel (Açores). Foi utilizada uma planta indicadora sensível para avaliar a fitotoxicidade deste substrato, geralmente utilizado por produtores agrícolas que pretendam enriquecer os seus solos de forma mais sustentável, a Brassica rapa ssp. pekinensis L. (couve chinesa), segundo a Norma Europeia EN 16086-1. Numa primeira etapa procedeu-se à caracterização do composto orgânico e da turfa utilizados como substratos no processo de envasamento do ensaio laboratorial, tendo sido avaliados os parâmetros físicos, químicos e biológicos. Após a caracterização dos substratos e da realização dos ajustes necessários, procedeu-se ao ensaio de germinação e crescimento da planta Brassica rapa ssp. pekinensis L. O ensaio foi dividido em três fases: (i) sementeira e germinação, (ii) crescimento e (iii) corte. Constatou-se que o composto utilizado apresentou menos inibição na proporção 25:75 (v/v) para todas as misturas, sendo a mistura com 24 g cal/L turfa o ensaio com menor inibição à germinação e ao crescimento. Além disso, a adição do composto nas duas proporções utilizadas nas diversas misturas (25/75 e 50/50, v/v de composto/turfa) promoveu o aumento do pH e da condutividade elétrica (CE) do substrato. O aumento do pH é benéfico; contudo, o aumento da CE poderá ter efeitos menos positivos no crescimento das plantas. Também foi possível concluir que se trata de um composto de boa qualidade (composto de classe II), podendo ser utilizado na agricultura, e com elevada estabilidade, quando avaliada pelos parâmetros biológicos
N/A

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Banzato, Ticyana Carone. "Mostarda-do-campo (Brassica rapa) um hospedeiro alternativo e cigarrinhas da espécie Agalia albidula um potencial vetor de um fitoplasma do grupo 16SrIII encontrado em campos de couve-flor". Universidade de São Paulo, 2014. http://www.teses.usp.br/teses/disponiveis/11/11135/tde-04022014-141422/.

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Plantas de mostarda-do-campo (Brassica rapa) exibindo intenso superbrotamento de ramos finos, com folhas e flores de tamanho reduzido, foram observadas em campos cultivados com couve-flor. Como os sintomas se mostravam similares àqueles induzidos por fitoplasmas, suspeitou-se que esta espécie daninha estava infectada por este tipo patógeno. Visando confirmar a diagnose, plantas foram amostradas e seu DNA extraído para ser usado em ensaios de duplo PCR, conduzidos com os iniciadores R16mF2/mR1, SN910601/SN011119, 16F2n/R2 e R16(III)F2/16(III)R. As amplificações de fragmentos genômicos correspondentes ao 16S rRNA revelaram uma constante associação entre um fitoplasma do grupo 16SrIII com as plantas sintomáticas. A doença foi denominada de superbrotamento. Cigarrinhas da espécie Agalia albidula foram coletadas nas áreas marginais e no interior dos campos de couve-flor, onde cresciam plantas de mostarda-do-campo. O DNA total foi extraído e usado em duplo PCR desenvolvido com os mesmos iniciadores citados anteriormente. Os resultados mostraram que os insetos analisados eram portadores de um fitoplasma do grupo 16SrIII. Para alguns isolados do fitoplasma encontrado em plantas de mostarda-do-campo, os produtos amplicados em duplo PCR com os iniciadores R16(III)F2/16(III)R foram sequenciados e confirmaram que as sequências pertenciam a um representante do grupo 16SrIII. Mapas de sítios putativos de restrição foram elaborados com o emprego de diversas endonucleases, porém não se logrou sucesso em definir a identidade deste fitoplasma ao nível de classificação de subgrupo. Com base nos resultados obtidos no presente estudo, plantas de mostarda-do-campo servem como hospedeiro alternativo de um fitoplasma do grupo 16SrIII, o qual foi anteriormente associado à doença conhecida como enfezamento, ocorrente em outras espécies de brássica, como repolho, brócolis e couve-flor. Assim, é sugerido que esta espécie daninha possa abrigar o agente de doença, garantindo sua sobrevivência e atuando como fonte de inóculo para as culturas comerciais. Além disto, cigarrinhas da espécie A. albidula podem ser apontadas como potenciais vetores do fitoplasma relacionado ao superbrotamento da mostarda-do-campo, bem como ao agente causal do enfezamento em brássicas. A presente pesquisa contribuiu para melhor compreensão dos aspectos relacionados aos enfezamentos das brássicas, envolvendo diversidade de fitoplasmas, gama de hospedeiros alternativos destes agentes de doença e ocorrência de vetores deste tipo de patógeno.
Mustard-field plants (Brassica rapa) showing intense shoots proliferation, small sized leaves and flowers, were observed in cauliflower production fields. Since the symptoms were similar to those induced by phytoplasmas, it was suspected that this weed was infected by this type of pathogen. To confirm the diagnosis, plants were sampled for DNA extraction to be used in nested PCR tests conducted with primers R16mF2/mR1, SN910601/SN011119, F6F2n/R2 and R16(III)F2/16(III)R. The amplification of genomic fragments corresponding to the 16S rRNA showed a constant association between a phytoplasma group 16SrIII with symptomatic plants. The disease was called witche\"s broom. Species of leafhopper, Agalia albidula, were collected in marginal areas and at cauliflower fields, where mustard-field plants grew. The total DNA was extracted and used in nested PCR carried out with the same primers mentioned above. The results showed that the insects analyzed were carriers of a phytoplasma group 16SrIII. For some isolates of phytoplasma found in mustard-field plants, the products obtained in nested PCR with primers R16(III)F2/16 (III)R were sequenced and confirmed that belonged to a representative 16SrIII group. Putative restriction sites maps, were prepared using a many restriction endonucleases, but no success has been achieved in defining the identity of the phytoplasma subgroup classification level. Based on the results in the present study, mustard-field plants could be an alternative host of a phytoplasma group 16SrIII, which was previously associated with the disease known as stunting, occurring in other species of rapeseed such as cabbage, broccoli and cauliflower. Thus, it is suggested this weed could harbor the disease agent, ensuring their survival and acting as a source of inoculum for commercial crops. Moreover, the species of leafhoppers, A. albidula, could be identified as a potential vector of the phytoplasma associated with witche\"s broom mustard-field as well as the causal agent of stunting in brassicas. This research contributed to understanding the issues related to stunting in brassicas, involving a diversity of phytoplasmas, range of alternative hosts of these disease agents and occurrence of vectors of this pathogen type.

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Elfar, Altamimi May. "Nitrate-nitrogen sufficiency ranges in leaf petiole sap of pac choi grown with organic and conventional fertilizers". Thesis, Kansas State University, 2010. http://hdl.handle.net/2097/6982.

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Master of Science
Department of Horticulture, Forestry, and Recreation Resources
Rhonda R. Janke
Petiole sap nitrate-nitrogen (NO3-N) analysis with handheld meters is a valuable tool in applying in-season nitrogen (N) for many crops. Sufficiency levels have been determined for several leafy green crops, including lettuce (Lactuca sativa L.) and cabbage (Brassica oleracea L.), but not for pac choi (Brassica rapa L.). The response of pac choi to different fertilizer rates and sources [conventional and organic] has established optimal soluble N application rates and Cardy meter sufficiency ranges. Greenhouse experiments were conducted during summer and fall of 2008 in Manhattan, KS. Conventional soluble fertilizer was formulated from inorganic salts with a 4 NO3-N: 1 ammonium ratio. Phosphorus was held at 1.72mM and K at 0.83mM for all treatment levels. The organic soluble fertilizer, fish hydrolyzate (2N:1.72P:0.83K), was diluted to provide the same N levels as with conventional treatments. Both fertilizers were applied at rates of 0, 32, 75, 150, 225, 300, and 450 mg. L-1. Seedlings were transplanted and fertilizer application began at 18 days. Plants were harvested at seven weeks (five weeks post transplanting) after receiving 15 fertilizer applications during production. Samples of the most recently matured leaves were harvested weekly and analyzed for petiole sap NO3-N and leaf blade total N concentration. Leaf count, leaf length, and chlorophyll content were also measured weekly. Fresh and dry weights were determined on whole shoots and roots. Optimum yield was achieved at the 150 mg. L-1 fertility rate with both conventional and organic fertilizers. Field and high tunnel experiments were conducted during fall 2008 to validate the sufficiency ranges obtained from the greenhouse studies. Based on field and high tunnel results, sufficiency levels of NO3-N for pac choi petiole sap during weeks 2 to 3 of production were 800-1500 mg. L-1, and then dropped to 600-1000 mg. L-1 during weeks 4 through harvest for both conventional and organic fertilizers sources. These ranges could vary based on the variety of the crop, the fertility of soil, and certain environmental factors such as photoperiod, light intensity. However, we found that petiole sap nitrate always increased to the point associated with the maximum biomass, followed by a plateau where sap nitrate remained constant. This characteristic of the Cardy meter can provide the growers with a practical methodology to generate their standard curves under specific conditions to guide in-season N applications. Total N in leaf tissue showed fewer fertilizer rate effects than petiole sap NO3-N. Chlorophyll content was not useful in evaluating pac choi N status.

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Boys, Emily Frances. "Resistance to Pyrenopeziza brassicae (light leaf spot) in Brassica napus (oilseed rape)". Thesis, University of Nottingham, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.556103.

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This project aimed to provide a greater understanding about resistance to Pyrenopeziza brassicae in oilseed rape. A doubled haploid population of Brassica napus derived from a cross between the resistant oilseed rape cultivar Imola and a susceptible breeding line was used to map a single major locus associated with resistance to P. brassicae. The locus was positioned at the end of the linkage group corresponding to chromosome A1, a region homeologous to Arabidopsis thaliana chromosome 3. The resistance was associated with a phenotype that involved reduced P. brassicae subcuticular hyphal growth, the collapse of epidermal cells and an absence of asexual sporulation. P. brassicae was, however, able to sporulate sexually on senescent leaf tissue of the resistant plants. For the doubled haploid population, there were significant correlations between severity of light leaf spot assessed on field plots in Hertfordshire and Scotland and severity assessed on seedlings in controlled environment conditions. Analysis using quantitative peR showed that the lines of the doubled haploid population differed in their ability to support the growth of P. brassicae in controlled environment (on cotyledons and young leaves) and field conditions. The resistance present in oil seed rape cultivar Imola is different from that observed in other B. napus cultivars/lines, where asexual sporulation was observed on even the least susceptible cultivars/lines, and currently appears stable in different parts of the UK. An improved understanding of resistance to P. brassicae in B. napus will help to inform decisions about the deployment of new resistant cultivars to maximise the durability of the resistance.

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