Literatura científica selecionada sobre o tema "Citrus Seedlings"
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Artigos de revistas sobre o assunto "Citrus Seedlings"
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Liberato, Érica Maria Sauer, Sarita Leonel, Jackson Mirellys Azevedo Souza e Gabriel Maluf Napoleão. "SUBSTRATE MIXING FORMULATIONS FOR CITRUS NURSERY MANAGEMENT". Nativa 9, n.º 5 (18 de dezembro de 2021): 500–507. http://dx.doi.org/10.31413/nativa.v9i5.12777.
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The length of citrus seedling development is determined by several factors, including the physical and chemical qualities of the substrate, which affect rootstock growth and, as a result, the quality of field seedlings. The purpose of this study was to see how the ‘Swingle’ citrumelo rootstock developed with different substrate formulations. The experiment was carried out in a seedling nursery from seeding to grafting, and six treatments were carried out, as follows: 60% peat moss, 30% fine grade horticultural vermiculite, 10% rice hulls (1); 60% peat moss, 30% fine grade horticultural vermiculite, 10% rice hulls (2); 50% peat moss, 30% fine grade horticultural vermiculite, 20% rice hulls (3); 50% peat moss, 30% fine grade horticultural vermiculite, 20% rice hulls (4); 50% peat moss, 20% fine grade horticultural vermiculite, 30% rice hulls (5); 50% peat moss, 20% fine grade horticultural vermiculite, 30% rice hulls (6). In addition, the experiment was divided into two stages: seeding (stage 1) and seedling nursery (stage 2). In a completely randomized design, the experiment has six treatments, four replications, and 51 plants per plot. When container transplanting was performed, the emergence percentage of seedlings was determined; thus, eight plants per plot were examined. For the second stage, was used a completely randomized design with 6 substrate formulations, 4 replications, and 20 seedlings per plot. Stem height, stem diameter, leaf number, area meter, root dry matter, leaf and stem dry matter, and quality index were measured on seedlings every 28 days. All substrate formulations improved seedling development until grafting, except for the 30% rice hulls, which hampered seedling development in ‘Swingle' citrumelo.
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Albrecht, Ute, e Kim D. Bowman. "Candidatus Liberibacter asiaticus and Huanglongbing Effects on Citrus Seeds and Seedlings". HortScience 44, n.º 7 (dezembro de 2009): 1967–73. http://dx.doi.org/10.21273/hortsci.44.7.1967.
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Huanglongbing (HLB) is a devastating disease of citrus and threatens the citrus industry worldwide. The suspected causal agent of the disease is a phloem-limited bacterium of the genus Candidatus Liberibacter transmitted through insect vector or grafting with diseased budwood. Currently, most seed source trees for citrus rootstock propagation are located outdoors and unprotected from disease transmission. In addition, fruit from HLB-affected scion varieties in Florida containing seeds enter the commercial trade and move into other citrus-growing areas. The objective of this study was to determine how Ca. L. asiaticus infection affects seed quality and seedling development and whether the disease appears in seedlings grown from infected fruit. Two experiments were conducted involving thousands of seedlings produced from seeds from infected rootstock seed source trees and ‘Valencia’ sweet orange trees, respectively. Infection of trees and fruit with Ca. L. asiaticus significantly reduced seed weight, seed germination, and seedling height. Seedlings did not develop symptoms typical of HLB throughout the experiment. Polymerase chain reaction (PCR) analysis initially identified two of 686 rootstock seedlings and three of 431 sweet orange seedlings positive for the pathogen when they were very young. Resampling and PCR analysis of these five seedlings at older ages consistently indicated they were negative for the pathogen and none of these plants ever developed symptoms of HLB. It is suggested that Ca. L. asiaticus may have been translocated into some part of the embryo during seed development but that it was not present in cells or tissue, which permitted replication or disease development as the seedling grew.
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Rieger, Mark. "Growth, Gas Exchange, Water Uptake, and Drought Response of Seedling- and Cutting-propagated Peach and Citrus Rootstocks". Journal of the American Society for Horticultural Science 117, n.º 5 (setembro de 1992): 834–40. http://dx.doi.org/10.21273/jashs.117.5.834.
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Growth, gas exchange, root hydraulic conductivity, and drought response of seedling and rooted cuttings of Lovell and Nemaguard peach [Prunus persica (L.) Batsch], and Carrizo (Poncirus trifoliata × Citrus sinensis) and sour orange (C. aurantium L.) citrus rootstocks were compared to determine the influence of propagation method on these characteristics. Rooted peach cuttings had a higher proportion of root biomass in fibrous roots (≤ mm in diameter) and lower root: shoot ratios than seedlings, although this did not occur in citrus. Net CO2 assimilation (A) was higher for peach seedlings than for cuttings, but similar for `Redhaven' (RH) scions on either seedling- or cutting-propagated rootstocks, suggesting that leaf-associated factors were responsible for differences. As in peach, A was higher for Carrizo seedlings than for cuttings, but A was not affected by propagation method in sour orange. Peach seedlings maintained higher A than cuttings as water potentials declined during short-term soil drying, although in citrus this occurred only for Carrizo. RH scions on either root type exhibited similar declines in A as soil dried, indicating the lack of a rootstock effect. Root hydraulic conductivity (Lp) was similar between seedlings and cuttings of all cultivars when expressed on a length basis. Leaf conductance and osmotic adjustment were similar for RH scions on seedling- or cutting-propogated rootstocks during 45 days of drought stress, indicating the lack of a rootstock effect on long-term stress response.
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dos Santos, Maria Ângela Cruz Macêdo, Mauricio Antônio Coelho Filho, Francisco José Nunes Modesto, Joseph M. Patt e Marilene Fancelli. "Behavioral Responses of Asian Citrus Psyllid (Hemiptera: Liviidae) to Salinity-Stressed Citrus". Environmental Entomology 50, n.º 3 (14 de abril de 2021): 719–31. http://dx.doi.org/10.1093/ee/nvab028.
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Abstract Most commercial citrus varieties are intolerant of salinity stress, but some rootstocks, such as Rangpur lime, tolerate moderately saline irrigation water. Development of salinity-tolerant citrus may allow for citriculture in semiarid and arid regions where salinity stress is problematic. Because salinity stress influences shoot growth in citrus, we compared the behavioral responses of Asian citrus psyllid, Diaphorina citri Kuwayama, to salinity-stressed versus nonstressed Rangpur lime seedlings. The effects of salinity stress on key physiological processes in the seedlings were also examined. Seedlings in the control group were fertilized with a solution having a salinity of 1.7 dS m−1 while seedlings in the salinity-stressed group were fertilized with a solution having a salinity of 10 dS m−1. The seedlings were exposed to salinity stress for increasing durations (15, 20, or 60 d). Seedlings presented differential physiological responses 15 d after the imposition of salinity stress, and differences in psyllid settling rate on control versus salinity-stressed seedlings were discernable within 1 h following the imposition of salinity stress. The levels of settling, oviposition, and egg survivorship were significantly lower on salinity-stressed versus control seedlings. Olfactometer tests showed that female psyllids preferred the odor from control seedlings, suggesting that the odors of control and salinity-stressed seedlings were different. The results showed that D. citri avoids salinity-stressed seedlings; this suggests the possibility of using moderate salinity stress as a management strategy to minimize psyllid settlement and reproduction and to reduce the spread of huanglongbing, especially in citrus grown in semiarid and arid areas.
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Dixon, R. K., H. E. Garrett e G. S. Cox. "Carbohydrate Relationships of Citrus jambhiri Inoculated with Glomus fasciculatum". Journal of the American Society for Horticultural Science 113, n.º 2 (março de 1988): 239–42. http://dx.doi.org/10.21273/jashs.113.2.239.
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Abstract Root exudation patterns and carbohydrate composition of roots and leaves of Citrus jambhiri Lush, were examined during the period of initial colonization by Glomus fasciculatum (Thaxt.) Gerd. and Trappe. Exudation of reducing sugars and amino acids from seedling roots decreased as soil and root P increased. Comparison of vesicular-arbuscular mycorrhizal (VAM) seedlings to nonmycorrhizal seedlings of similar size and P nutrition revealed root exudation in VAM plants decreased following fungal colonization. Root reducing sugars increased and root starch content decreased in VAM seedlings during the infection process. Following establishment of symbiosis, leaves of VAM seedlings had greater levels of total soluble sugar, sucrose, reducing sugars, and starch relative to nonmycorrhizal controls. Colonization of C. jambhiri roots by VAM fungi apparently alters the balance of carbohydrates within leaves and roots.
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Sykes, SR. "Effects of seedling age and size on chloride accumulation by juvenile citrus seedlings treated with sodium chloride under glasshouse conditions". Australian Journal of Experimental Agriculture 25, n.º 4 (1985): 943. http://dx.doi.org/10.1071/ea9850943.
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Chloride accumulation by juvenile citrus seedlings treated with sodium chloride for 56 days, using either nutrient solution culture (50 mM NaCl) or pot culture (75 mM NaCl) techniques under glasshouse conditions, was investigated in relation to seedling age. Ranking of cultivars on the basis of leaf chloride concentrations varied according to the age of seedlings examined. Leaf chloride concentrations of 6-, 5-, 4- and 3-month-old seedlings of eight cultivars examined in solution culture decreased with seedling age and were negatively correlated with seedling dry weight within some cultivars. Cultivar differences in leaf chloride concentrations, which occurred for all age groups, were negatively correlated with shoot growth and seedling dry weight for 5-month-old seedlings only. Leaf chloride concentrations of seedlings treated with NaCl in pot culture also changed with the age of seedlings (5, 17- and 29-monthsold) and varied between cultivars, with significant cultivar x age interactions. The effect of seedling size on chloride accumulation was investigated using nutrient solution culture. Six-month-old seedlings of four varieties were treated with NaCl (50 mM) for 56 days. Two size classes were obtained by growing seedlings at two densities before salt treatment. Small seedlings had greater shoot chloride concentrations than equivalent large seedlings and cultivar ranking, based on shoot chloride concentrations, changed with seedling size. Cultivar differences in leaf chloride concentrations were negatively correlated with seedling growth and dry weight for small seedlings but not for large seedlings. Seedling size had no effect on root chloride concentrations. The results suggest that screening very small seedlings for chloride exclusion is not feasible since rankings based on leaf chloride concentrations did not agree with documented data for grafted trees. There appeared to be a critical or threshold seedling age or size at or above which rankings for shoot chloride accumulation by good chloride excluders were consistent with documented field data. The results are discussed in relation to screening citrus hybrids for chloride exclusion under glasshouse conditions.
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Bowman, Kim D., Frederick G. Gmitter e Xulan Hu. "Relationships of Seed Size and Shape with Polyembryony and the Zygotic or Nucellar Origin of Citrus spp. Seedlings". HortScience 30, n.º 6 (outubro de 1995): 1279–82. http://dx.doi.org/10.21273/hortsci.30.6.1279.
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We examined the relationship between seed size and shape in Citrus and the number and type of seedlings produced by individual seeds for each of three citrus cultivars. Seed size and shape were related to the number of seedlings produced and the likelihood of recovering a zygotic seedling. The relationship between seed size and shape and the likelihood of recovering a zygotic seedling most often was connected with weight and thickness of a seed. This relationship might be of sufficient strength to use in some aspects of cultivar development. However, the relationship did not appear strong enough to be of practical value for application in commercial production of purely nucellar rootstock seedlings.
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Bisi, Rayane Barcelos, Ute Albrecht e Kim D. Bowman. "Seed and Seedling Nursery Characteristics for 10 USDA Citrus Rootstocks". HortScience 55, n.º 4 (abril de 2020): 528–32. http://dx.doi.org/10.21273/hortsci14598-19.
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Six new hybrid rootstocks, ‘US-1279’, ‘US-1281’, ‘US-1282’, ‘US-1283’, ‘US-1284’, and ‘US-1516’, were released from the U.S. Department of Agriculture (USDA) citrus breeding program to provide improved tree tolerance to huanglongbing (HLB), the most destructive disease facing the citrus industry in the United States and many other parts of the world. Five of these new rootstocks were released based on field performance in trials with the rootstocks propagated by stem cuttings, rather than the traditional propagation using nucellar seedlings. In this study, we evaluated the fruit, seed, and seedling characteristics of these new rootstocks, along with four other USDA rootstocks of commercial importance. The study included a determination of the percentage of true-to-type and off-type seedlings by both plant morphology and simple sequence repeat (SSR) markers. All 10 rootstocks produced an acceptable number of seeds and good seedling emergence from those seeds. The rootstocks ‘Swingle’, ‘US-802’, ‘US-812’, ‘US-1283’, ‘US-1284’, and ‘US-1516’ had a high percentage of true-to-type seedlings and correspondingly good potential to be propagated by seeds. However, no true-to-type plants were observed among seedlings from the rootstocks ‘US-1279’, ‘US-1281’, and ‘US-1282’, indicating that economical seed propagation will be impossible for these cultivars. The 10 SSR marker sets used in this study were observed to easily differentiate the 10 rootstocks studied, and readily distinguished true-to-type and off-type seedlings among progeny from all 10 rootstock clones. This study presents information of significant value for commercial nurseries involved in propagation of citrus rootstocks, and those involved in citrus rootstock breeding and development around the world. We propose the use of these 10 SSR marker sets as readily applicable for accurate identification of most citrus rootstock cultivars and their true-to-type seedlings.
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Al-Shahwany, Ayyad W., Fatima K. Mohammad e Ropak Tofiq. "Influence Soaking Gibberellin acid on seed germination for Citrus limetta and Citrus limonum and their seedlings growth". Journal of Biotechnology Research Center 8, n.º 1 (1 de janeiro de 2014): 43–49. http://dx.doi.org/10.24126/jobrc.2014.8.1.301.
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Study was undertaken to test the effects of soaking seeds Citrus limetta and Citurs limonum in Gibberellic acid (GA3) solutions 0, 100, 500, 1000 mg / L for 24 hours prior on the rate of germination, some morphological characteristics for seedlings also were investigated in this study. Factorial experiment was carried out 4×2×5 in a randomized complete block design with five replicates for each type of seed during the period of March to September 2011. The results showed significant differences in most traits, as it reached the highest percentage of germination for the treatment with 500 mg/l for both types of seeds, while the highest dry and fresh weights of shoot and root, main root length, highest shoot, leaves number and leaf area index were in 1000 mg /l treatment. No significant effect of GA3 treatment on the amount of A, B and total chlorophyll in the seedlings leaves. The best treatment was soaking seed in 1000gm/l Gibberellic acid. The information documented the stimulating effects of seedling be used to increase the ratio of germination. Also gibberellins stimulated effects continues for some seedlings morphological characteristics and progressively with gibberellins seed treatments influence vary according to genotypes of citrus seeds, that can increase concentrations which used in soaking seeds solutions.
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Anderson, Catalina M., William S. Castle e Gloria A. Moore. "Isozymic Identification of Zygotic Seedlings in Swingle Citrumelo Citrus paradisi × Poncirus trifoliata Nursery and Field Populations". Journal of the American Society for Horticultural Science 116, n.º 2 (março de 1991): 322–26. http://dx.doi.org/10.21273/jashs.116.2.322.
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Isozyme analysis was the basis for determining the frequency of occurrence and the characteristics of zygotic plants in Swingle citrumelo seedling populations from various sources of open-pollinated seeds, in a commercial nursery of Swingle citrumelo before and after roguing, and in commercial orchards and rootstock trials where this rootstock was used. Most zygotic seedlings identified by isozyme analysis could be distinguished by careful examination of morphological characteristics. Frequencies of zygotic seedlings varied among seedling populations, but were in the range (≈5% to 10%) found in previous studies. Roguing based primarily on size and growth habit of seedlings was effective in removing some, but not all, zygotic seedlings. Most of the remaining zygotic plants in the rogued population were found among the smaller seedlings. Trees budded on zygotic rootstock seedlings were found in two of the three groves studied, and in some instances an apparent incompatibility was developing in young trees.
Teses / dissertações sobre o assunto "Citrus Seedlings"
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Ashari, Ir Sumeru. "Discrimination between citrus genotypes". Title page, contents and summary only, 1989. http://web4.library.adelaide.edu.au/theses/09A/09aa819.pdf.
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Sitole, Phumeza. "Investigating the role of mycorrhizal fungi and associated bacteria in promoting growth of citrus seedlings". Thesis, Rhodes University, 2014. http://hdl.handle.net/10962/d1013033.
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South Africa is the world's second largest exporter of fresh citrus and is ranked 14th in citrus production. Fungal pathogens such as Phytophthora and Pythium cause economic losses as a result of root rot and brown rot. Mycorrhizal fungi are specialized members of the fungal community forming a mutualistic relationship with plant roots. Mycorrhizal fungal structures are known to associate with other soil microorganisms and these may contribute to improved plant growth. A diverse group of bacteria that interact with the mycorrhizal fungi are known as Mycorrhizal Helper Bacteria (MHB). The aim of this study was to investigate the role of arbuscular mycorrhiza and associated bacteria isolated from spores and determine whether they had any plant growth promoting potential. A total of 19 bacteria were isolated from arbuscular mycorrhizal spores and were molecularly identified as belonging to several Bacillus, Micrococcus, Onchrobactrum and Staphylococcus sp. All bacterial isolates were tested for plant growth promotion abilities. One Bacillus isolate was able to solubilise phosphate. Four isolates Micrococcus sp, Micrococcus leteus, Ochrobacterum sp and Ochrobacterum antropi were able to produce Indole Acetic Acid and three isolates showed potential to reduce growth of Phytophthora nicotianae, P. citrocola and P. citrophthora in in vitro plate cultures. Further tests using culture supernatants of the Bacillus sp, Micrococcus sp and Bacillus cereus confirmed their ability to inhibit or reduce growth of the three Phytophthora species in a 96 well bioassay. Bacillus sp and Bacillus cereus were able to inhibit Phytophthora spp by 95 to 100 % and Micrococcus spp was able to decrease pathogen growth by 60 to 94 %. These bacterial isolates were further evaluated for plant growth promoting abilities on citrus rough lemon seedlings alone or in combination with arbuscular mycorrhizal inoculum. Bacterial and mycorrhizal inoculants influence the increase in shoot and root biomass. Bacillus cereus in combination with mycorrhizal inoculum significantly increased seedling shoot to root ratio while root biomass was significantly increased with mycorrhizal inoculation. Due to the short duration of the trial mycorrhizal colonisation could not be assessed. It is evident that selected combinations of bacteria and mycorrhizal fungi could promote citrus seedling growth and potentially improve seedling health. Further studies under nursery conditions are recommended.
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Muchena, Lindsay. "Improved growth of hydroponically-grown rough lemon (Citrus jambhiri Lush) seedlings treated with kelp and vermi extracts". Diss., University of Pretoria, 2017. http://hdl.handle.net/2263/65918.
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A substantial number of South African citrus trees are rooted on rough lemon rootstocks. In order to ensure the successful establishment of a high percentage of young citrus trees, it is necessary to ensure that farmers are provided with young vigorous nursery trees that have a large and healthy root system. Vermicast extracts (VE) and liquid extracts from the giant seaweed, Ecklonia maxima (EM), have been used on various crops over the past decades to promote plant growth and development. It is widely reported that plant growth, seedling vigour, water-use efficiency and nutrient-uptake of these crops improves with EM and VE treatments, thereby reducing excessive fertiliser applications. With the improved uptake of nutrients such as nitrogen (N), which is the main component of chloroplasts and proteins involved in the Calvin cycle, it is likely that the application of EM and VE to plants could lead to an improvement in the photosynthetic capacity of plants. The benefits from applications of EM and VE have been attributed to the presence of plant growth regulators/hormones (PGRs) such as auxins and cytokinins. Since seaweed extracts are manufactured using different methods, some of which may include the use of elevated temperatures, acid and/or alkaline hydrolysis of plant material, it is not surprising that different seaweed extracts may contain various levels of PGRs which can lead to dissimilarities in their growth promoting effects. A hydroponic experiment was conducted to test if locally produced EM from two different suppliers and VE would increase root length, root volume, root dry mass, stem diameter, plant height, chlorophyll content, nutrient uptake and photosynthetic capacity of rough lemon seedlings. The other objective of this study was to determine if there was any difference in growth promoting effects of EM obtained from two different supplies due to the difference in the levels of plant growth regulators they contain. Since the action of EM and VE is dose dependant, it was also necessary to determine the optimum concentration of EM and VE for the growth of rough lemon seedlings. This experiment was conducted in a glasshouse at the University of Pretoria experimental farm. Liquefied Ecklonia maxima from different manufactures; Ecklonia maxima - Kelpak® and Ecklonia maxima – Afrikelp® (EM1 & EM2 respectively); and vermicast extracts (VE) were applied separately to rough lemon seedlings as a drench (at 0.5%, 1% and 2% dilutions), at 14 day intervals. Deionized water and full strength Hoagland solution were used as controls. Root volume, root length, stem diameter, plant height, chlorophyll content and photosynthesis were measured weekly for 12 weeks. At the end of the trial, the average root dry mass and shoot dry mass for each treatment was determined. Upon termination of the trial, oven dried leaf samples were analysed for nitrogen (N), phosphorus (P), potassium (K) and calcium (Ca). N analysis was done at an accredited commercial lab whilst P, K and Ca analyses were done at the University of Pretoria using ICP-OES.Dissertation (MSc (Agric))--University of Pretoria, 2017.
Plant Production and Soil Science
MSc (Agric)
Unrestricted
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Sibhatu, Mebrahtu Berhane. "Cloning and Sequencing of Glucosyltransferase (GT) Genes from Grapefruit (Citrus paradisi) Seedlings, Searching for 7-O-GT". [Johnson City, Tenn. : East Tennessee State University], 2003. http://etd-submit.etsu.edu/etd/theses/available/etd-0713103-183831/unrestricted/SibhatuM072103a.pdf.
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Thesis (M.S.)--East Tennessee State University, 2003.Title from electronic t.p. ETSU ETD database URN: etd-0713103-183831. Includes bibliographical references. Also available via Internet at the UMI web site.
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Cabrera, Ronaldo Alberto Duenhas. "Produção de mudas cítricas em viveiro: uso de substrato alternativo e inoculação com Xylella fastidiosa". Universidade de São Paulo, 2004. http://www.teses.usp.br/teses/disponiveis/91/91131/tde-20092004-155806/.
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Substratos alternativos têm sido usados para promover um melhor estabelecimento de plantas em viveiros, de forma a assegurar que plantas sadias sejam transferidas ao campo. No caso do Citrus spp. Esta preocupação é real pela possibilidade do campo poder apresentar um histórico de doenças na área, tal como a Clorose Variegada do Citros causada pela Xylella fastidiosa (X.f.). Este estudo avaliou a adição de vermicomposto a um substrato comercial e o desenvolvimento de plântulas de quatro variedades de citros inoculadas ou não com X.f. em condições de casa-de-vegetação, por um período de 450 dias. Medidas biométricas do crescimento da planta e o uso de indicadores do balanço nutricional usando o programa DRIS - Diagnosis and Recommendation Integrated System foram aplicadas em plantas de 9 meses de idade. As variáveis estudadas foram: substrato vermicomposto (100%, 50%, 0%) , variedade (Baia, Pêra, Natal e Escape) e inoculação (com ou sem X.f.) em um total de 24 tratamentos (variedade x substrato x inoculação), com seis repetições. Quanto ao desenvolvimento das plantas, avaliou-se o diâmetro do caule, a altura da planta, a produção de biomassas das raízes e partes aéreas, a taxa de infecção natural por fungos micorrízicos naturais do solo, a concentração de macro e micronutrientes na parte aérea. Quando se usou vermicomposto (100% or 50%), efeitos positivos foram observados nos parâmetros de desenvolvimento das plantas. Por outro lado, a infecção micorrízica e DRIS foram inversamente correlacionadas indicando estar ocorrendo um desbalanço nutricional neste estádio de desenvolvimento das plantas. Não foi observado um efeito significativo da inoculação com X.f. no desenvolvimento das plantas ou mesmo nos parâmetros biométricos, exceto para os teores foliares de nitrogênio e fósforo, onde nas plantas inoculadas o teor foliar de nitrogênio (1,46%) foi maior em relação às plantas não inoculadas (1,30%) e para fósforo ocorreu o oposto (0,32% e 0,40%, respectivamente).Alternative substrates have being used for a better establishment of plants at nursery stages, thus ensuring that healthier plants will be transferred to the field. In the case of Citrus, this is a concern especially when there is a past history of diseases at field conditions, such as Citrus Variegated Chlorosis caused by Xylella fastidiosa (X.f.). This study evaluated the addition of vermicompost to a commercial substrate and the performance of seedlings of four citrus varieties inoculated or not with X. f. at greenhouse condition, for a period of 450 days. Biometric measurements of plant growth and nutritional balance indicators using DRIS - Diagnosis and Recommendation Integrated System were performed in 9 month-old plants. Mycorrhizal infection by native vesicular-arbuscular fungi was also evaluated in all plants. The studied variables were: vermicompost substrate (100%, 50%, 0%), variety (Baia, Pêra, Natal and Escape) and inoculation (with or without X.f.), in a total of 24 treatments (variety x substrate x inoculation) with 6 replicates each. Growth development evaluated stem diameter, plant height, shoot and root biomass accumulations, arbuscular mycorrhizal infection, and macro and micronutrient concentration in the shoot. When using vermicompost (100% or 50%), positive effects were observed in the plant growth parameters. On the other hand, mycorrhizal infection and DRIS were inversely correlated to the substrate addition, indicating that nutrient imbalances may be occurring at this plant growth stage. No significant effect of X.f. inoculation was observed on the plant growth and the biometric parameters studied, except for increased foliar nitrogen content - 1,46% for inoculated and 1,30% for uninoculated plants, and decreased foliar phosphorus content - 0,32% for inoculated and 0,40% for uninoculated plants.
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Melo, Jaila Ferreira [UNESP]. "Avaliação de isolados de Trichoderma spp. para controle de Phytophthora nicotianae". Universidade Estadual Paulista (UNESP), 2015. http://hdl.handle.net/11449/132431.
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A cultura da laranja no Brasil é afetada por várias doenças, como a gomose, causada por Phytophtora nicotianae Breda de Haan (synonymous whit P. parasítica Dast.), cujo controle é comumente realizado com aplicações de fungicidas e medidas de exclusão. Porém, devido aos custos financeiros e problemas ambientais ocasionados pelo uso intenso destas aplicações, faz-se necessário a busca por métodos alternativos de controle. Este trabalho teve por objetivo avaliar 50 isolados de Trichoderma spp. como antagonista de P. nicotianae, sendo que os isolados foram avaliados, através da produção de compostos antimicrobianos por meio destes microrganismos, além da realização de um bioensaio com plântulas de alfafa. No cultivo pareado observou-se que todos os isolados inibiram o crescimento micelial do fitopatógeno. Na produção de compostos antimicrobianos, 41 isolados produziram compostos voláteis utilizando dextrose como fonte de carbono. No entanto, em estudos posteriores, foi verificado que a utilização de sacarose ou maltose como fontes de carbono, aumentou a produção destes compostos. Sete isolados de Trichoderma produziram compostos termoestáveis e 14 produziram compostos antimicrobianos livres de células do antagônico. No bioensaio com plântulas de alfafa foi observado que quatro isolados de Trichoderma inibiram a formação de esporângios e de micélios do fitopatógeno. Diante dos resultados obtidos, concluiu-se que as avaliações in vitro com relação à produção de compostos antimicrobianos pelos isolados de Trichoderma e o bioensaio com plântulas de alfafa mostraram capacidade para selecionar isolados com potencial para o controle de P. nicotianae. Os isolados TB12, TB14, TB28 e TB 30 foram os que proporcionaram maior controle da doença.
Orange crops in the Brazil are affected by various diseases such as gummosis caused by Phytophtora nicotianae Breda de Haan (synonymous whit P. parasítica Dast.), which is controlled by chemical fungicides. However, the high costs and environmental problems caused by the intensive use of these fungicides have led to the search for alternative methods of control. The objective of this study was to evaluate the antagonistic activity of 50 Trichoderma spp. isolates against P. nicotianae by the production of antimicrobial compounds and an alfalfa seedling bioassay. The paired culture showed that all isolates tested inhibited the mycelial growth of the pathogen. In the production of antimicrobial compounds, 41 isolates produced volatile compounds using dextrose as carbon source; however, further assays showed that the use of sucrose or maltose as carbon source increases the production of these compounds. Seven isolates of Trichoderma spp. produced thermostable compounds and 14 isolates produced cell-free culture antimicrobial compounds of the antagonist. In the alfalfa seedling bioassay, four isolates of Trichoderma spp. inhibited the formation of sporangia and mycelia growth. The evaluation in vitro concerning to the antimicrobial compound production by the Trichoderma spp. isolates and the alfalfa seedling bioassay both were able to select biocontrol agents to control of P. nicotianae. The Trichoderma spp. isolates, TB12, TB14, TB28, and TB30 presented the best disease control.
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Martins, Madles Queiroz. "Desenvolvimento de cinco porta-enxertos cítricos e do enxerto variedade folha murcha em ambientes com diferentes níveis de sombreamento". Universidade Federal do Espírito Santo, 2011. http://repositorio.ufes.br/handle/10/6638.
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Previous issue date: 2011-12-22A variação na intensidade luminosa sobre plantas de determinada espécie pode levar a diferentes respostas em suas características fisiológicas, bioquímicas, anatômicas e de crescimento. O objetivo deste trabalho foi avaliar a influência de ambientes com diferentes níveis de sombreamento no desenvolvimento de diferentes porta-enxertos cítricos e da combinação porta-enxerto Limoeiro Cravo enxertado com a variedade de laranjeira Folha Murcha. Para isso, foram conduzidos três experimentos. No primeiro experimento, avaliou-se o desenvolvimento dos porta-enxertos na fase de sementeira compreendendo o período da semeadura até a fase de transplantio. O segundo experimento correspondeu às avaliações no período compreendido entre o transplantio dos porta-enxertos até o ponto de enxertia. O terceiro experimento trata da avaliação do crescimento da combinação enxerto da variedade Folha Murcha sobre porta-enxerto Limoeiro Cravo. O primeiro e o segundo experimentos foram instalados e conduzidos em propriedade particular localizada na cidade de Alegre-ES, situada a 20º49 de latitude sul e 41º32 de longitude oeste e a 322 m de altitude. O terceiro foi instalado no Centro de Ciências Agrárias da Universidade Federal do Espírito Santo, localizado no município de Alegre-ES, situado a 20º45 de latitude sul e 41º32 de longitude oeste de Greenwich e a 271 m de altitude. O delineamento utilizado no primeiro e segundo experimentos foi inteiramente casualizado no esquema de parcela subdividida 4x5, sendo quatro ambientes com 0%, 30%, 50% e 80% de sombreamento e cinco variedades de porta-enxerto (Limoeiro Cravo, Limoeiro Volkameriano, Poncirus Trifoliata, Flying Dragon e Citrumelo Swingle), com quatro repetições e vinte e cinco sementes por parcela no primeiro, e três plantas por parcela no segundo experimento. No terceiro experimento, foi utilizado o delineamento inteiramente casualizado, no qual os tratamentos foram compostos por quatro ambientes 0%, 30%, 50% e 80% de sombreamento, utilizando-se o a variedade Folha Murcha enxertada sobre o portaenxerto Limoeiro Cravo. No primeiro experimento, foram avaliados: percentagem de emergência, índice de velocidade de emergência, número de folhas, altura, área foliar, massa seca da parte aérea, massa seca das raízes e teor de clorofila total (a+b). No segundo experimento, foram avaliados área foliar, número de folhas, diâmetro do caule a 10 centímetros do coleto, altura das plantas, teor de clorofila total (a+b) e massa seca da parte aérea e das raízes. No terceiro, foram avaliados diâmetro do porta-enxerto medido dois cm do ponto da enxertia, diâmetro do enxerto a 10 cm, comprimento do enxerto, área foliar, número de folhas e massa seca da parte aérea. Da semeadura até o transplantio, o sombreamento em 50% (luminosidade média de 249,06 μmol m-2 s-1) proporciona maior vigor às mudas. As diferentes variedades dos porta-enxertos podem ser cultivadas nas mesmas condições de sombreamento. Na fase pós-transplantio e enxertia, o maior crescimento das mudas ocorre na ausência de sombreamento
The variation in light intensity on plants species can lead to different responses in their physiological, biochemical, anatomical and growth. The objective of this study was to evaluate the influence of environments with different levels of shading in the development of different rootstocks of citric and combination variety of rootstocks Rangpur lime grafted with a variety of orange tree withered leaves. With this purpose three experiments were conducted. In the first experiment evaluated the development of rootstocks on phase comprising the period from seed sowing to transplanting phase. The second experiment with the assessments for the period from transplanting to the point of rootstocks grafting. The third experiment evaluated the growth of the graft combination of variety on leaf wilt rootstocks Rangpur Lime. The first and second experiment were conducted on private property and located in the city of Alegre-ES, located at 20º 49 south latitude and 41º 32 west longitude and 322 m altitude. The third was installed at the Centro de Ciências Agrárias da Universidade Federal do Espírito Santo, located in the municipality of Alegre-ES, located at 20º 45 south latitude and 41º 32 longitude west of Greenwich e a 271 m de altitude. The design in the first and second experiments was completely randomized in a split-plot 4x5, four environments 0%, 30%, 50% and 80% shading and five varieties of rootstock (Rangpur Lime, Lemon Volkameriano, Poncirus Trifoliata, Flying Dragon and Citrumelo Swingle) with four repetitions and twenty-five seeds per plot in the first, and three plants per plot in the second experiment. In the third experiment was used a randomized design in which treatments were composed of four environments 0%, 30%, 50% and 80% shading, using him to wilt leaf variety rootstocks grafted on Rangpur Lime. In the first experiment were evaluated emergence percentage, emergence speed index, leaf of number, height, leaf area, shoot dry mass, dry mass of roots and total chlorophyll (a + b). In the second experiment were evaluated leaf area, leaf number, stem diameter at 10 cm of the collar, plant height, total chlorophyll (a + b) and dry mass of shoots and roots. In third were evaluated rootstocks diameter measured two inches from the point of grafting, the graft diameter 10 cm, length of the graft, leaf area, leaf number and dry weight of shoots. From sowing to transplanting the shading to 50% (average brightness of 249,06 mol m-2 s-1) provides greater strength to the seedlings. Rootstocks of the different varieties can be grown under the same conditions of shading. In the post transplanting and grafting the highest plant growth occurs in the absence of shading
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莊文忠. "Effect of waterlogging on growth citrus rookstock seedlings". Thesis, 2004. http://ndltd.ncl.edu.tw/handle/26708919876426097542.
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碩士國立臺灣大學
園藝學研究所
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Citrus seedlings, which transplanted in 25 cm high pet pod with quartz sand for 2 weeks, were used in this research, to select waterlog tolerant citrus rootstock at a plastic tunnel in National Taiwan University. Six rootstocks, Sunki, Rangpur lime, sour orange, Cleopatra mandarin, ‘Swingle’ citrumelo and ‘Troyer’ citrange, were tested in the first experiment, waterlogged for 4 weeks from Sep, 26 to Oct, 17 2002. Then Sunki, ‘Swingle’ citrumelo and ‘Troyer’ citrange which had showed significant response were selected for the subsequent experiment and were waterlogged for 6 weeks from Mar, 28 2003. In the first experiment, roots of all rootstocks rotted after 1 week of waterlogging. Shoot growth retarded and leaves turned yellow after 3 and 4 weeks respectively. In the condition of high underground water, root rot appeared in all rootstocks during 4-7 days after treatment and adventitious root grew after 2-4 weeks of waterlogging. The plant growth of the plant in the second experiment approximated to those of the first one. Sunki had the most number of fallen leaves and ‘Troyer’ the least. After 6 weeks of waterlogging ‘Swingle’ citrumelo and ‘Troyer’ citrange began to establish new root system above submerged zone and Sunki developed less adventitious roots. The contents of N, K, Ca and Mg in leaves of all waterlogged plants decreased but the content of Fe increased. The contents of P, Zn and Mn did not change significantly. Root had similar consequence with Fe accumulation to 2000-3000 mg/kg. The contents of carbohydrates also increased, especially in 80% EtOH Soluble Sugar. The shoot growth of ‘Swingle’ citrumelo and ‘Troyer’ citrange resumed after 1 week of drainage. The leaves of Sunki fell after 1 week of drainage and new leaves grew 6 weeks later. In terms of growth potential, ‘Swingle’ citrumelo and ‘Troyer’ citrange were more tolerant to waterlogging and recovered more quickly after drainage. However, Sunki was hurt severely after waterlogging and took longer to recover after drainage.
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Ashari, Ir Sumeru. "Discrimination between citrus genotypes". Thesis, 1989. http://hdl.handle.net/2440/109045.
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Abraham, Abraha Okbasillasie. "Biological control of Phytophthora root rot of citrus seedlings and cuttings". Thesis, 2005. http://hdl.handle.net/10413/3830.
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With an increasing realization that many agrochemicals are hazardous to animals and humans, came the desire to replace these chemical agents with biological approaches that are more friendly to the environment and human health. Microorganisms play an important role in plant disease control, as naturally occurring antagonists. Microorganisms may also have beneficial
effects on plant development when applied to plant roots. Research efforts worldwide have recorded successes in biological control and growth stimulation on many crops, particularly when using members of the genera Bacillus and Trichoderma. Their use on citrus rootstock could be advantageous to nurserymen and growers in reducing the incidence of seedling mortality and increasing production. To achieve these objectives, laboratory and tunnel experiments were conducted to develop effective biocontrol agents for citrus seedlings and cuttings. Nineteen 0 ut 0 f 23 Trichoderma isolates tested in vitro against Phytophthora p arasitica sp
showed antagonistic activity by hyperparasitism and four out of eight Bacillus isolates resulted in antagonism by forming inhibition zones. The positive in vitro activity of Trichoderma and Bacillus isolates on Phytophthora provided motivation step for further trials in the greenhouse to evaluate their biological control activity on citrus seedlings and cuttings. A greenhouse trial was carried out to evaluate the biological control potential of 23 Trichoderma isolates (drenched at 5 x 105 spores / rnI) and two Bacillus isolates (drenched at 1 X 106 or 1 X 108 colony forming units (CFU) / rnI) to suppress Phytophthora parasitica sp. of rough lemon (Citrus jambhirini Lush.) seedlings. Five isolates ofTrichoderma (AA12, AA5, Trichoderma harzianum (AA16), SY3F and Eco-T~ were highly effective in suppressing Phytophthora root rot, with AA12 providing the best control. The Bacillus isolates also suppressed the pathogen but were not as effective as the Trichoderma isolates. This trial was used to test for growth stimulation activity by some of the biocontrol agents. To verify these results, a further trial was carried out to evaluate growth stimulation capabilities in the absence of any pathogen. Trichoderma Isolates AA13 and AA17 caused no 111 change in seedling growth, while other Trichoderma and Bacillus isolates had an inhibitory effect on the seedling growth. This trial indicated that the biocontrol activity was affected by
inoculum densities, and as a result in vitro sporulation capacity was evaluated. TrichodermaIsolate AA16 was the largest spore producer, followed by Eco-T®. Spore production was lowest from Trichoderma isolates AA4 and AA12. Growth stimulation responses of Trichoderma Isolates AA4, AA16, Eco-TID and SYN6 were further studied at four different doses (1 X 103, 1 X 104, 5 X 105 or 1 X 106 spores / ml) on rough lemon and trifoliate orange seedlings. Trifoliate oranges responded positively to 1 X 104 and 5 X 105 spores / ml of Eco-TID, but rough lemon responded negatively to all dosages of the Trichoderma isolates applied. This indicates that the inoculum density responses may be host specific. Higher population density of 1 X 106 spores / ml of all tested Trichoderma isolates had a stunting effect on seedling growth of both species. Based on t he positive results 0 f individual applications of some Trichoderma and Bacillus isolates, of the biological control agents on rough lemon seedlings against Phytophthora
parasitica in an earlier greenhouse trial, their combined effect in the control of the pathogen was performed. Before carrying out a greenhouse trial, activities of the isolates to be combined were evaluated in vitro. This trial showed that Trichoderma Isolates AA16 and Eco-T®were compatible. Trichoderma isolates AA16 and Eco-T®were also found to be compatible with
Bacillus Isolates B77, B81 and PHP. As a result, further in vivo trials were conducted. The tunnel trials were carried out as two separate experiments:
In the first experiment, a combination of two Trichoderma Isolates A A 16 and Eco-T®was conducted assayed at 5 X 105 or 1 X 106 spores / ml, on rough lemon seedling, and cuttings and trifoliate orange and sour orange seedlings. A combination of Trichoderma isolate AA16 and Eco-T®at 5 X 105 spore / ml increased significantly the new flush biomass of rough lemon cuttings compared to AA16 alone, but was not different from Eco-TID alone. The combination of AA16 and Eco-T® achieved no change of biomass of rough lemon and trifoliate orange seedlings. The combination of AA16 and Eco-TID did not increase the root biomass of sour orange compared to AA16 or Eco-r® alone. The combination of AA16 and Eco-r® at higher doses (1 x 106 spores / ml) showed significantly better suppression of Phytophthora root rot of rough lemon cuttings but did not show disease suppression in all seedling species verities tested. In a second experiment, individual and combined effects of Trichoderma isolates (drenched at 5 X 105 spores / ml) with Bacillus isolate (drenched at 1 X 106 colony forming units (CFU) / ml) for suppression of Phytophthora root rot on rough lemon and trifoliate orange seedlings was performed. The combination of Trichoderma Isolate AA16 and Bacillus Isolate B81 increased root biomass on rough lemon seedlings compared to the combination of Trichoderma AAI6 or Bacillus PHP but was not significantly different to Trichoderma AA16 alone. Bacillus PHP combined with Trichoderma AA16 or singly had no effect on rough lemon seedlings. Combining Trichoderma Eco--r® and with Bacillus B8I or PHP did not increase biomass of rough lemon seedlings compared to Trichoderma Isolate Eco--r® alone. There was no statistically significant differences in the effects of the combinations of the Trichoderma and Bacillus isolates compared to their individual applications on the biomass of trifoliate oranges. This study established the antagonistic potential of several South African isolates of
Trichoderma and Bacillus as a viable alternative to agrochemicals for controlling Phytophthora parasitica. The growth stimulation capabilities of Trichoderma isolates in terms of seedling development was also demonstrated.Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2005.
Livros sobre o assunto "Citrus Seedlings"
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Zekri, Mongi. Effects of sodium chloride and polyethylene glycol on the water relations, growth, and morphology of citrus rootstock seedlings. 1987.
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Teague, R. M. Principles and Practices of Citrus and Tropical Fruit Culture from the Nursery Tree to the Full Bearing Orchard [microform]: Together with Timely Suggestions on Harvesting, Packing, and Marketing, Based on Thirty-Three Years' Experience in Southern Calif. Creative Media Partners, LLC, 2018.
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Teague, R. M. Principles and Practices of Citrus and Tropical Fruit Culture from the Nursery Tree to the Full Bearing Orchard [microform]: Together with Timely Suggestions on Harvesting, Packing, and Marketing, Based on Thirty-Three Years' Experience in Southern Calif. Creative Media Partners, LLC, 2018.
Encontre o texto completo da fonteCapítulos de livros sobre o assunto "Citrus Seedlings"
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Alva, A. K., e E. Q. Chen. "Hydrogen ion inhibition of copper uptake by citrus seedlings". In Plant-Soil Interactions at Low pH: Principles and Management, 631–34. Dordrecht: Springer Netherlands, 1995. http://dx.doi.org/10.1007/978-94-011-0221-6_100.
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Villegas-Monter, Angel, Elisa Del Carmen Matínez-Ochoa, María Andrade-Rodriguez e Itzel Villegas-Velázquez. "Citrus Polyembryony". In Advances in Citrus Production and Research [Working Title]. IntechOpen, 2022. http://dx.doi.org/10.5772/intechopen.105994.
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Polyembryony is a type of sporophytic apomixis common in citrus species. Previous studies discovered that embryo traits relate to their sexual or asexual origin. Smaller embryos at the micropyle end are considered zygotic embryos, whereas larger embryos are nucellar. Early embryogenesis in the ovule of apomictic citrus promotes the development of nucellar embryos. The chalaza region inhibits the early development of the zygotic and nucellar embryos; thus, both embryos must grow at the micropyle end. Numerous researchers agree that highly polyembryonic cultivars produce nucellar seedlings more often as the zygotic embryos cannot survive field conditions. Thus, the selection of polyembryonic genotypes facilitates clonal propagation. This chapter analyzes the factors that affect polyembryony in citrus.
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Julienne, Nguefack, Fouelefack François Romain, Dongmo Lekagne Joseph Blaise, Azah Udom Rene, Dongmo Nanfack Albert, Djoufack Metis Molière e Nkengfack Augustin Ephrem. "Effects of Seed Treatments Using Extracts of Oxalis barrelieri L. and Cymbopogon citratus Stapf, Coupled with NaCl Sorting on Seed Health, Germination, Emergence and Seedlings Vigor, of Rice (Oryzae sativa L.) Seeds". In Cutting-edge Research in Agricultural Sciences Vol. 6, 82–100. Book Publisher International (a part of SCIENCEDOMAIN International), 2021. http://dx.doi.org/10.9734/bpi/cras/v6/1917d.
Texto completo da fonteTrabalhos de conferências sobre o assunto "Citrus Seedlings"
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Kender, Walter J. "Citrus Canker: Impacts of Research on Eradication and Control". In ASME 1986 Citrus Engineering Conference. American Society of Mechanical Engineers, 1986. http://dx.doi.org/10.1115/cec1986-3204.
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Citrus Bacterial Canker Disease (CBCD), caused by Xanthomonas campestris pv. citri, occurs in many citrus areas of the world. It has been reported in 40 different countries, on 5 continents (Asia, South Africa, Australia, South America and North America). Prior to the 1984 outbreak in Florida, the 4 known strains of the bacterium were A, B, C and Mexican bacterioses. Canker-A or Strain-A, endemic in Asia, was reported in China, India and Java in the early 1800’s, found in Japan in 1899 and in the Philippines in 1914. It affects most citrus species and hybrids. Grapefruit is especially susceptible. Strain-A was introduced into the United States from Japan on trifoliate orange seedlings in 1910. An eradication program was started in 1915 in Florida and the disease was eradicated in 1927. In South America, the Asiatic form was not found until 1957 in Brazil and 1972 in Argentina. In 1979, the A Strain broke out in the commercial citrus area of Sao Paulo State, Brazil. Paper published with permission.
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Kobayashi, Felipe Kawashita, Andrea Britto Mattos, Maysa M. G. Macedo e Bruno H. Gemignani. "Citrus Tree Classification from UAV Images: Analysis and Experimental Results". In XV Workshop de Visão Computacional. Sociedade Brasileira de Computação - SBC, 2019. http://dx.doi.org/10.5753/wvc.2019.7624.
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The use of unmanned aerial vehicles (UAVs) and computer vision for automating farm operations is growing rapidly: time-consuming tasks such as crop monitoring may be solved in a more efficient, precise, and less error-prone manner. In particular, for estimating productivity and managing pests, it is fundamental to characterize crop regions into four classes: (i) full-grown trees, (ii) tree seedlings, (iii) tree gaps, and (iv) background. In this paper, we address the classification of images from citrus plantations, acquired by UAVs, into the previously mentioned categories. While Deep learning-based methods allow to achieve high accuracy values for classification, explainability remains an issue. Therefore, our approach is to run an experimental analysis that allows to derive the effects of different parametrizations (involving descriptors, classifiers, and sampling methods) when applied to our citrus dataset.
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Grosser, Jude W. "The Role of Biotechnology in the Development of Improved Citrus Scion and Rootstock Cultivars". In ASME 1992 Citrus Engineering Conference. American Society of Mechanical Engineers, 1992. http://dx.doi.org/10.1115/cec1992-3802.
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The development of improved citrus and scion rootstock cultivars has been limited by several factors, including complex reproductive biology, extended juvenility, and a lack of support and continuity of long-termed conventional breeding programs (Gmitter et al., 1991). Most commercially important scion and rootstock cultivars have arisen from the selection of bud-sport mutations within existing clones or by chance seedling selections. However, there are a few important scion and rootstock cultivars that were developed by conventional breeding. Such scion cultivars are mandarin hybrids developed by USDA breeders, primarily tangelos (mandarin x grapefruit hybrids) and tangors (mandarin x sweet orange hybrids) including ‘Minneola’, ‘Orlando’, ‘Nova’, ‘Page’, ‘Robinson’, ‘Fairchild’, ‘Sunburst’ (Saunt, 1990), and more recently ‘Fall Glo’ and ‘Ambersweet’ (C.J. Hearn, personal communication). Important rootstock cultivars developed by conventional breeding include Swingle citrumelo (grapefruit x trifoliate orange hybrid) and Carrizo and Troyer citranges (sweet orange x trifoliate orange hybrid). Because of renewed interest and the development of improved breeding parents, sexual hybridization will play an increasingly important role in citrus cultivar improvement. The integration of emerging biotechnologies with conventional breeding methods will facilitate and expedite citrus cultivar improvement. Paper published with permission.
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Ida Bagus Komang, Mahardika, Sulistiawati Ni Putu Anom e Astiari Ni Komang Alit. "Applying of length shoots to Determine the Success of Grafting to Effort Supplying of Citrus Plant Seedling". In Proceedings of the 1st Warmadewa Research and Development Seminar (WARDS),30 October 2018, Denpasar-Bali, Indonesia. EAI, 2019. http://dx.doi.org/10.4108/eai.30-10-2018.2281458.
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Tian, Fangming, Shujuan Yi, Feng Tan, Xiaoliang Wang, Li Yan, Yingnan Liu e Donglai Han. "Research on Intelligent General Acquisition Controller of Rice Seedling-nursery House in Cold Region Based on MSP430F5438". In 2012 National Conference on Information Technology and Computer Science. Paris, France: Atlantis Press, 2012. http://dx.doi.org/10.2991/citcs.2012.166.
Texto completo da fonteRelatórios de organizações sobre o assunto "Citrus Seedlings"
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Porat, Ron, Doron Holland e Linda Walling. Identification of Citrus Fruit-Specific and Pathogen-Induced Promoters and Their Use in Molecular Engineering. United States Department of Agriculture, janeiro de 2001. http://dx.doi.org/10.32747/2001.7585202.bard.
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This one year BARD project was funded to develop methods to monitor promoter activity a gene expression patterns in citrus fruit. To fulfill this goal, we divided the research tasks between both labs so that the Israeli side evaluated the use of microprojectile bombardment ; a tool to evaluate transient gene expression in various citrus fruit tissues, and the US side optimized technical parameters required for Agrobacterium-mediated transformation of various citrus cultivars. Microprojectile bombardment appeared to be a very efficient method for transient gene expression analysis in citrus leaf tissues but was somewhat less applicable in fruit tissues. Nevertheless, we did succeeded to achieve significant levels of 35S-GUS gene expression in young green flavedo tissue. However, only single random spots of 35S-GUS gene expression were detected mature flavedo and in juice sacs and albedo tissue. Overall, we assume that following some more technical improvements particle bombardment could provide a useful technique to rapidly analyze promoter activity at least in the flavedo tissue. For Agrobacterium-mediated transformation, we found that shoot cultures of 'Washington' navel oranges,'Fairchild' mandarins,'Eureca' lemons,'Troyer' citrange and various grapefruits provided a more reliable and consistent source of tissue for transformation than germinated seedlings. Moreover, various growth media's (McCown, Quoirin & Lepoivre, DCR) further improved shoot and root growth relative to MS mineral media, which is commonly used. Also pure white light (using bulbs which do not emit UV or blue light) improved shoot growth in various citrus varieties, and paromomycin appeared to be a more efficient antibiotic for the selection of transgenic plants than Kanamycin. Overall, these optimizations improve transformation efficacy and shoot growth and rooting capacity. In addition to the development of transformation methods, both Israeli and US labs achieved progress in the identification of citrus fruit-specific promoters. In Israel, we isolated a 3.6 kb promoter fragment of the thiamine biosynthesis c-thi gene, which is highly expressed in fruit peel tissue, whereas in the US we isolated a 1.5 kb promoter fragment of the citrus seed-specific cDNA CssH. The identification of more fruit-specific cDNAs and their corresponding promoter regions is currently in progress.
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Sadka, Avi, Mikeal L. Roose e Yair Erner. Molecular Genetic Analysis of Citric Acid Accumulation in Citrus Fruit. United States Department of Agriculture, março de 2001. http://dx.doi.org/10.32747/2001.7573071.bard.
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The acid content of the juice sac cells is a major determinant of maturity and fruit quality in citrus. Many citrus varieties accumulate acid in concentrations that exceed market desires, reducing grower income and consumer satisfaction. Pulp acidity is thought to be dependent on two mechanisms: the accumulation of citric acid in the vacuoles of the juice sac cells, and acidification of the vacuole. The major aim of the project was to direct effort toward understanding the mechanism of citric acid accumulation in the fruit. The following objectives were suggested: Measure the activity of enzymes likely to be involved in acid accumulation and follow their pattern of expression in developing fruit (Sadka, Erner). Identify and clone genes which are associated with high and low acid phenotypes and with elevated acid level (Roose, Sadka, Erner). Convert RAPD markers that map near a gene that causes low acid phenotype to specific co dominant markers (Roose). Use genetic co segregation to test whether specific gene products are responsible for low acid phenotype (Roose and Sadka). Objective 1 was fully achieved. Most of the enzymes of organic acid metabolism were cloned from lemon pulp. Their expression was studied during fruit development in low and high acid varieties. The activity and expression of citrate synthase, aconitase and NADP-isocitrate dehydrogenase (IDH) were studied in detail. The role that each enzyme plays in acid accumulation and decline was evaluated. As a result, a better understanding of the metabolic changes that contribute to acid accumulation was achieved. It was found that the activity of the mitochondrial aconitase is greatly reduced early in high-acid fruits, but not in acidless ones, suggesting that this enzyme plays an important role in acid accumulation. In addition, it was demonstrated that increases in the cytosolic forms of aconitase and NADP-IDH towards fruit maturation play probably a major role in acid decline. Our studies also demonstrated that the two mechanisms that contribute to fruit acidity, vacuolar acidification and citric acid accumulation, are independent, although they are tightly co-regulated. Additional, we demonstrated that sodium arsenite, which reduce fruit acidity, causes a transient inhibition in the activity of citrate synthase, but an induction in the gene expression. This part of the work has resulted in 4 papers. Objective 3 was also fully achieved. Using bulked segregant analysis, three random amplified polymorphic DNA (RAPD) markers were identified as linked to acitric, a gene controlling the acidless phenotype of pummelo 2240. One of them, which mapped 1.2 cM from acitric was converted into sequence characterized amplified region (SCAR marker, and into co dominant restriction length polymorphism (RFLP) marker. These markers were highly polymorphic among 59 citrus accessions, and therefore, they should be useful for selecting seedling progeny heterozygous for acitric in nearly all crosses between pummelo 2240 and other citrus genotypes. This part of the project resulted in one paper. Objective 4 was also fully achieved. Clones isolated by the Israeli group were sent to the American laboratory for co segregation analysis. However, none of them seemed to co segregate with the low acid phenotype. Both laboratories invested much effort in achieving the goals of Objective 2, namely the isolation of genes that are elevated in expression in low and high acid phenotypes, and in tissue cultures treated with arsenite (a treatment which reduces fruit acidity). However, conventional differential display and restriction fragment differential display analyses could not identify any differentially expressed genes. The isolation of such genes was the major aim of a continuation project, which was recently submitted.
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Moore, Gloria A., Gozal Ben-Hayyim, Charles L. Guy e Doron Holland. Mapping Quantitative Trait Loci in the Woody Perennial Plant Genus Citrus. United States Department of Agriculture, maio de 1995. http://dx.doi.org/10.32747/1995.7570565.bard.
Texto completo da fonteResumo:
As is true for all crops, production of Citrus fruit is limited by traits whose characteristics are the products of many genes (i.e. cold hardiness). In order to modify these traits by marker aided selection or molecular genetic techniques, it is first necessary to map the relevant genes. Mapping of quantitative trait loci (QTLs) in perennial plants has been extremely difficult, requiring large numbers of mature plants. Production of suitable mapping populations has been inhibited by aspects of reproductive biology (e.g. incompatibility, apomixis) and delayed by juvenility. New approaches promise to overcome some of these obstacles. The overall objective of this project was to determine whether QTLs for environmental stress tolerance could be effectively mapped in the perennial crop Citrus, using an extensive linkage map consisting of various types of molecular markers. Specific objectives were to: 1) Produce a highly saturated genetic linkage map of Citrus by continuing to place molecular markers of several types on the map. 2) Exploiting recently developed technology and already characterized parental types, determine whether QTLs governing cold acclimation can be mapped using very young seedling populations. 3) Determine whether the same strategy can be transferred to a different situation by mapping QTLs influencing Na+ and C1- exclusion (likely components of salinity tolerance) in the already characterized cross and in new alternative crosses. 4) Construct a YAC library of the citrus genome for future mapping and cloning.
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Guy, Charles, Gozal Ben-Hayyim, Gloria Moore, Doron Holland e Yuval Eshdat. Common Mechanisms of Response to the Stresses of High Salinity and Low Temperature and Genetic Mapping of Stress Tolerance Loci in Citrus. United States Department of Agriculture, maio de 1995. http://dx.doi.org/10.32747/1995.7613013.bard.
Texto completo da fonteResumo:
The objectives that were outlined in our original proposal have largely been achieved or will be so by the end of the project in February 1995 with one exception; that of mapping cold tolerance loci based on the segregation of tolerance in the BC1 progeny population. Briefly, our goals were to 1) construct a densely populated linkage map of the citrus genome: 2) map loci important in cold and/or salt stress tolerance; and 3) characterize the expression of genes responsive to cold land salt stress. As can be seen by the preceding listing of accomplishments, our original objectives A and B have been realized, objective C has been partially tested, objective D has been completed, and work on objectives E and F will be completed by the end of 1995. Although we have yet to map any loci that contribute to an ability of citrus to maintain growth when irrigated with saline water, our very encouraging results from the 1993 experiment provides us with considerable hope that 1994's much more comprehensive and better controlled experiment will yield the desired results once the data has been fully analyzed. Part of our optimism derives from the findings that loci for growth are closely linked with loci associated with foliar Cl- and Na+ accumulation patterns under non-salinization conditions. In the 1994 experiment, if ion exclusion or sequestration traits are segregating in the population, the experimental design will permit their resolution. Our fortunes with respect to cold tolerance is another situation. In three attempts to quantitatively characterize cold tolerance as an LT50, the results have been too variable and the incremental differences between sensitive and tolerant too small to use for mapping. To adequately determine the LT50 requires many plants, many more than we have been able to generate in the time and space available by making cuttings from small greenhouse-grown stock plants. As it has turned out, with citrus, to prepare enough plants needed to be successful in this objective would have required extensive facilities for both growing and testing hardiness which simply were not available at University of Florida. The large populations necessary to overcome the variability we encountered was unanticipated and unforeseeable at the project's outset. In spite of the setbacks, this project, when it is finally complete will be exceedingly successful. Listing of Accomplishments During the funded interval we have accomplished the following objectives: Developed a reasonably high density linkage map for citrus - mapped the loci for two cold responsive genes that were cloned from Poncirus - mapped the loci for csa, the salt responsive gene for glutathione peroxidase, and ccr a circadian rhythm gene from citrus - identified loci that confer parental derived specific DNA methylation patterns in the Citrus X Poncirus cross - mapped 5 loci that determine shoot vigor - mapped 2 loci that influence leaf Na+ accumulation patterns under non-saline conditions in the BC1 population - mapped 3 loci that influence leaf Na+ accumulation paterns during salt sress - mapped 2 loci that control leaf Cl- accumulation patterns under non-saline conditions - mapped a locus that controls leaf Cl- accumulation patterns during salt stress Screened the BC1 population for growth reduction during salinization (controls and salinized), and cold tolerance - determined population variation for shoot/root ratio of Na+ and Cl- - determined levels for 12 inorganic nutrient elements in an effort to examine the influence of salinization on ion content with emphasis on foliar responses - collected data on ion distribution to reveal patterns of exclusion/sequestration/ accumulation - analyzed relationships between ion content and growth Characterization of gene expression in response to salt or cold stress - cloned the gene for the salt responsive protein csa, identified it as glutathione peroxidase, determined the potential target substrate from enzymatic studies - cloned two other genes responsive to salt stress, one for the citrus homologue of a Lea5, and the other for an "oleosin" like gene - cold regulated (cor) genes belonging to five hybridization classes were isolated from Poncirus, two belonged to the group 2 Lea superfamily of stress proteins, the others show no significant homology to other known sequences - the expression of csa during cold acclimation was examined, and the expression of some of the cor genes were examined in response to salt stress - the influence of salinization on cold tolerance has been examined with seedling populations - conducted protein blot studies for expression of cold stress proteins during salt stress and vice versa