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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Cranberry nutrients, phenology, and nitrogen-phosphorus-potassium

DeMoranville, Carolyn J 01 January 1992 (has links)
The objective of this study was to compile and interpret nutritional and developmental data for cranberry (Vaccinium macrocarpon Ait.) as the basis for standardizing experimental techniques (particularly data collection) and tissue analysis, including tissue to sample, time of sampling, and normal element concentrations for 'Early Black'. Seasonal nutrient levels were determined in tissues of 'Early Black' cranberry under 10N-8.7P-8.3K fertilization (O, 170, 335, and 505 kg/ha). After three years, N, P, and K concentrations in new shoot tissues were positively affected by N-P-K supply. The N-P-K supply had no effect on Ca and Mg concentrations in new shoot tissue but B concentrations were lowest in unfertilized plants. N, P, K, and Cu concentrations in new shoots declined during the season, whereas those of Ca, Mg, B, and Mn rose. Element concentrations in the tissues indicated that mobilization of elements into new shoots from old leaf and woody stem tissues occurred. In an average crop (17 Mg/ha), 8.5 kg N/ha and 14.7 kg K/ha were removed from the cranberry bog. Vegetative growth (dry weight, upright length) was positively correlated with N-P-K supply, but the highest yields were associated with 335 kg N-P-K/ha. Upright density, percent of uprights flowering, and fruit set were the important determinants of yield. These variables were proposed as standards for data collection. Growing degree day (GDD) accumulations were recorded during this study using a base temperature of 6.5C (lower than previously recommended). Based on GDD accumulations at the canopy level, the correct base temperature for cranberries is most likely 4.5C or lower. However, for a single location over several years, day number was superior to GDD as a predictor of developmental and nutritional status. A period of stable element concentration in new shoot tissue (10 August to 15 September) was identified and recommended as the time to collect cranberry tissue samples for analysis. Mixed vegetative and flowering new upright tips were recommended as the tissue to sample, and standards for 'Early Black' were proposed. Element concentrations in 'Howes', 'Stevens', 'Pilgrim', 'Bergman', and 'Franklin' were determined and compared to the 'Early Black' standard values.
2

Propagation by budding with special reference to the cherry

Simpson, Ray Clinton. January 1905 (has links)
"Thesis submitted for the degree of B.S.A."
3

A study of the tissue culture and genetic manipulation of rubber (Hevea brasiliensis)

Wilson, Zoe Amanda January 1989 (has links)
No description available.
4

Development of a protocol for the micropropagation of mature Eucalyptus grandis clones through somatic embryogenesis

Tsewana, Andiswa January 2001 (has links)
Dissertation submitted in compliance with the requirements for the Master's Degree in Technology: Biotechnology, Technikon Natal, 2001. / Biotechnology techniques such as micropropagation VIa somatic embryogenesis offer potential significant advances in the improvement of forest species, which could sustain forest production in South Africa, as well as globally, without increased use of land. In order to apply such techniques to commercial breeding and clonal programmes of E. grandis species, it is necessary to develop reliable and efficient protocols applicable to explants of proven superior genotypes. Most of the research on E. grandis somatic embryogenesis has used the genetically variable embryos or seedlings as explant sources, which results in the propagation of material of unproven genetic value. In order to exploit somatic embryogenesis maximally for cloning of superior trees, somatic embryos have to be induced from highly selected and, hence, mature trees. The aim of this investigation was to develop such a protocol for E. grandis and to test its applicability to various E. grandis hybrids. Somatic embryos were induced from buds, stems, leaves and petioles, with petioles and buds giving the best results. Thus, these were selected for further studies which involved testing the effect of medium composition on embryogenic callus induction. Media used for this purpose contained MS or B5 nutrients, 1 mg.l' 2,4-D, 0.5 g.r! glutamine, 0.5 g.r! casein hydrolysate, 4 g.r! Gelrite and 30 or 50 g.rl sucrose. All the media tested were able to support induction of embryogenic callus, although the number of explants producing embryogenic calli was affected significantly by the media composition (10-91 %). Callus induction media with B5 nutrients seemed to have a significant effect onn the developmental stage of embryos in the callus induction medium. Presence of 50 g.r! sucrose in the callus induction medium reduced the embryo yield, but the progress of embryo development was enhanced. The callus induction medium containing B5, 1 mg.l' 2,4-D, 0.5 g.rl glutamine, 0.5 g.r! casein hydrolysate, 4 g.r! Gelrite and 30 g.l' sucrose was chosen for subsequent studies. Of all the media tested for embryo development, the medium with B5, 2.5 mg.l' 2iP, 0.5 g.r! glutamine, 0.5 g.r! casein hydrolysate, 4 g.r! Gelrite and 50 g.r! sucrose was found to be the most suitable for embryo development to the cotyledonary stage. Experiments involving incorporation of both ABA and 2iP aiming at maturation of E. grandis somatic embryos led to an increase in size of the cotyledonary embryos formed but not to germination. / M
5

Factors affecting the rooting of Eucalyptus cuttings

Price, Ian Cameron, 1936- January 1961 (has links)
No description available.
6

Studies of the bud failure disorders of almonds in California /

Schein, Richard David. January 1952 (has links)
Thesis (Ph. D.)--University of California, (Davis), 1952. / Degree granted in Plant Pathology. Includes bibliographical references (leaves 69-71). Also available via the World Wide Web. (Restricted to UC campuses).
7

Studien über den einfluss von nitriten auf die keimung von samen und auf das wachstum von pflanzen ...

Schultz, Max Bruno Wolfgang, January 1903 (has links)
Inaug.-diss.--Königsberg i. Pr.
8

Soilless culture of moringa (Moringa oleifera Lam.) for the production of fresh biomass

Crosby, George William 01 January 2007 (has links)
The many medicinal, nutritional, industrial, and agricultural uses of moringa are well documented, although studies remain focused on moringa as a wild, uncultivated plant and little horticultural research has been devoted to its culture. Greenhouse experiments were conducted at the State University of New York at Cobleskill, New York, USA during the summer of 2006. Soilless culture has been investigated as an alternative production system for medicinal and aromatic plants, and moringa seedlings were grown using hydroponic and aeroponic culture at a pH of 5.5-6.0 and electrical conductivity levels of 2.0-2.3 dS˙m-1 in order to maximize leaf biomass production and gain access to root biomass. Moringa leaves are valued for their human nutritional benefits and as a livestock feed, however the monopodial growth habit of moringa requires removal of the terminal growing point in order to encourage branching and maximize leaf production. Seedlings are often subjected to extreme levels of vegetative harvest when grown in high-density agroforestry production systems, often resulting in high levels of mortality. Seedling decapitation induced outgrowth of lateral buds, and no lateral buds were released by intact plants that were not decapitated. The release from apical dominance was repressible by the application of exogenous auxin (0.5% IAA) to the stumps of decapitated seedlings. Seedlings decapitated to node 6 (15 cm, counted acropetally) released buds more quickly and produced three times the dry weight per plant than seedlings decapitated to node 1 (5 cm). Seedlings decapitated to 30 cm (approximately 12 nodes) released 2 more buds per plant and twice the dry weight compared to those decapitated to 40 cm (approximately 16 nodes). Pinching seedlings to remove 5 or 10 cm of apical stem resulted in little regrowth with few buds released and low dry weights. The percentage of stem removed was more important than the actual height to which a seedling was decapitated in order to maximize regrowth. Twice-decapitated plants released more buds (6.7/plant) than once-decapitated plants (2.7/plant), demonstrating enhanced lateral bud response of previously decapitated seedlings. The effect of four different pruning strategies on leaf biomass production of young, pollarded moringa trees was also examined.
9

Factors influencing colonization and establishment of plant species on cranberry bogs

Sandler, Hilary A 01 January 2004 (has links)
The objective of this study was to obtain and interpret field data related to the establishment of cranberry (Vaccinium macrocarpon Ait.) plantings, as well as examine the impact of conventional weed management practices on yield components and weed control. Integrated weed management, recently recognized by weed scientists as a desired goal for research and extension, is an important part of current cranberry production. This research was designed to permit the incorporation of the collected data into practical grower recommendations, as well as to expand our general knowledge about invasion ecology and plant species composition in new and established commercial plantings. Data from four years of repeat annual applications of 0, 1.8, and 4.5 kg ai/ha dichlobenil in low-weed and high-weed density areas indicated minimal negative impact on cranberry vines. Herbicide application did not adversely affect upright productivity, biomass, fruit set, or other yield parameters; in addition, no improvements for these parameters were noted. No consistent treatment effect on cranberry root length was seen. The presence of weeds, rather than herbicide application, was the important determinant of yield. Vines in low-weed density areas produced more marketable fruit and had higher percentage fruit set than vines growing in high-weed density areas. Results suggest that repeat annual applications of dichlobenil to commercial cranberry beds may be considered as part of a viable integrated weed management program with no adverse effect on crop growth or yield. One specific goal of this research was to identify the most beneficial combination of nitrogen rate, vine planting density, and weed management option that would promote quick and economical vine establishment of the cultivar, Stevens, while providing adequate and cost-effective weed control. After two years, several treatment combinations seemed promising for commercial implementation. However, the most cost-effective production scheme for establishing a new planting was to plant vines at a low density, use moderate rates of nitrogen, and apply a yearly application of napropamide for weed control. This combination produced substantial vine coverage at very low cost, reduced weed biomass by 85% compared to the untreated plots, and gave the best control per dollar spent.
10

Genetic analysis of the breakdown of self-incompatibility in Lycopersicon peruvianum

Chawla, Bindu 01 January 1996 (has links)
In the first part of the thesis, experiments are described where self-compatible tetraploids of L. peruvianum were isolated from tissue culture and the expression and inheritance of their S-related proteins was explored. The S-related protein profiles of styles of self-compatible tetraploids were indistinguishable from the diploid self-incompatible explant source based on SDS-PAGE. Progenies obtained from self-fertilization of two tetraploids were all found to be self-compatible. Cloned cDNA sequences of the S-related proteins were used to determine the inheritance at the locus in these progenies through Southern hybridization. The allelic ratio consistent with the predicted ratio obtained if only the pollen bearing two different alleles was successful in achieving fertilization. This work demonstrates that the observed self-compatibility in the tetraploids was due to failure of recognition of heterogenic pollen by the style, while the expression and activity of the S-related stylar proteins remained unaffected. In the second part of the thesis, periclinal chimeras between the SI L. peruvianum (P) and the SC L. esculentum (E) were utilized to analyze the relative influence of apical cell layers as they relate to SI and Unilateral incompatibility (UI). Irrespective of the expression of S-proteins in the chimeral styles, the chimeras were compatible with P component indicating that there was failure of recognition of the "self" pollen (the chimeras and the P component are genetically similar at the S-locus). The breakdown of SI was not related to the RNase activity of the S-proteins which was intact in all chimeras. Therefore S-proteins are not sufficient to maintain the SI response. Since the response was lost if either of the two layers (L1 and L2) was composed of E component, we conclude that both L1 and L2 are required for the SI phenotype. On the other hand, UI response was maintained in all the chimeras in which the L1 or L2 layer was P. This seems to suggest that SI and UI responses are developmentally unrelated in these chimeras.

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