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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.
281

Distribution of prune dwarf and necrotic ringspot viruses in Prunus tissues and behavior of the viruses in seeds

Megahed, El-Sayed Abdel Aziz, January 1969 (has links)
Thesis (Ph. D.)--University of Wisconsin--Madison, 1969. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.
282

A curriculum for teaching the fruit of the Spirit to a Christian high school Bible class

Judd, Robyn Michelle. January 2002 (has links)
Thesis (M.A.)--Gordon-Conwell Theological Seminary, South Hamilton, MA, 2002. / Abstract. Includes bibliographical references (leaves 58-59).
283

Enhancement of vegetative growth in young citrus plantings

Mudzunga, Maluta J. 03 1900 (has links)
Thesis (MSc)--Stellenbosch University, 2000. / Full text to be digitised and attached to bibliographic record. / ENGLISH ABSTRACT: Enhancement of vegetative growth in young citrus plantings The establishment of citrus involves high input costs, with break-even usually only attained after six years, making early returns imperative for economic survival. Early production is inseparably associated with good growth of the trees in the non-bearing years. In cool and cold production regions, coupled with a high frequency of wind, the initial tree growth is unsatisfactory. Trials were conducted to evaluate the effect of foliar application of Progibb® (GA3), Promalin'" (G~+7 + BA), Kelpak® (seaweed extract containing auxins and cytokinins) and soil applications of Temik® (aldicarb) as a means to promote vegetative growth. GA3 and/or aldicarb significantly increased tree height, without increasing the stem diameter in comparison to the control trees on 'Eureka' lemon, but not on 'Lisbon' lemon. G~+7 + BA or Kelpak® treatments did not have an effect on tree growth or fresh weight distribution. In conclusion, growth stimulation by GA3 and/or aldicarb could lead to quicker filling of the allotted space, and consequently higher, earlier yields, but further trials are required to verify these results. Insufficient carbohydrate and nitrogen reserves are often implicated in poor establishment performance of nursery trees. The effect of tree size at planting and different topping heights on early growth in the field were evaluated; also the physical and chemical profile of tall nursery whip trees were quantified. Significant correlations were found between the initial stem diameter and final stem diameter and initial tree height and final tree height at the end of the first growing season. Stem diameter increase was significantly reduced in topped trees relative to untopped trees. Roots comprised approximately 22%, and the aboveground portion about 78% of total dry weight. Roots nearly always contained higher concentrations of carbohydrates and nitrogen reserves. However, the aboveground sections, comprising a higher proportion of total dry weight, contained more than two thirds of total carbohydrates and nitrogen reserves. Topping of nursery whip trees at 60 cm aboveground thus would result in a loss of 33 to 37% dry matter, 29 to 33% carbohydrates and 37 to 46% nitrogen. Therefore, planting large, untopped nursery trees enhance initial tree growth in the orchard. The use of well-branched nursery trees for orchard planting can shorten the time to commercial fruit production. Citrus nursery trees do not develop lateral shoots adequately in the nursery or in the field and therefore necessitate various branch induction techniques. Two trials on newly-planted (one or five months after planting) trees were conducted to evaluate various branch induction techniques, viz., girdling, Promalin® (G~+7 + BA) (at 1000 or 2000 mg/I) and/or leaf removal and notching either to individual buds or the whole trees. The first trial, on l-month-old trees did not yield significant results. In the second trial, notching and girdling significantly increased the number and total length of lateral branches, but notching was the most effective technique. As the first trial, on the very young trees, yielded no significant results, it seems that trees have to be well established before they will respond. In young, non-oearing trees a lot of energy is invested in the flowering process, which results in an inhibition of vegetative growth. Gibberellic acid (GA3) and heavy mineral oil (Bac-oil) treatments, either individually or in combination, applied during early winter were evaluated as a means to reduce flowering levels in young nonbearing citrus trees. GA3 and mineral oil either separately or in combination were sprayed from April to July to the whole tree. GA3 and mineral oil either individually or in combination applied late in May to late June markedly reduced flowering. GA3 application in mid April had a minimal effect on flowering levels. Peak responses to GA3 coincided with a significant reduction in bud sprouting. Although optimum application time proved to be around May to July, this time is likely to vary from year to year depending on the influence of the prevailing temperature and other climatic conditions. The winter application of GA3, specifically, and possibly in combination with mineral oil to inhibit flowering and early vegetative growth may be utilised commercially. However, response may vary dramatically from season to season. Effect of time of application and concentration of 2,4-dichlorophenoxypropionic acid (2,4-DP) and l-naphthaleneacetic acid (NAA) as potential fruit thinning agents to reduce fruit set soon after flowering and enhance vegetative growth were evaluated over a two year period. 2,4-DP at 150 and 300 mg/I and NAA at 200 and 400 mg/! were sprayed on 2- and 4-year-old 'Mihowase' Satsuma, as well as on 2-year-old 'Marisol', 'Nules' and 'Oroval' Clementine trees at two times (late October and early November). The higher concentration of 2,4-DP and NAA generally did not result in increased fruit abscission in the first year. However, in the case of 2,4-DP the higher concentration resulted in stronger thinning in the second year. 2,4-DP and NAA can be used as potential fruit thinning agents to reduce fruit set on young non-bearing trees. / AFRIKAANSE OPSOMMING: Verbetering van vegetatiewe groeie by jong sitrus-aanplantings Die vestiging van sitrus behels hoë insetkoste en die gelykbreekpunt word gewoonlik eers na ses jaar bereik. Vroë opbrengste is dus noodsaaklik vir ekonomiese oorlewing. In koel en koue produksie-areas, met baie wind, is die aanvanklike boomgroei onvoldoende. Studies is uitgevoer om die effek van blaarbespuitings van Progibb'" (GA3), Promalin® (G~+7 + BA), Kelpak (seewier-ekstrak wat ouksien en sitokiniene bevat) en grondtoedienings van Temik® (aldicarb), as metodes om vegetatiewe groei te verbeter te evalueer. GA3 en/of aldicarb het boornhoogte betekenisvol laat toeneem, sonder om stamdeursnit te bevoordeel op 'Eureka' suurlemoen, maar nie op 'Lisbon' suurlemoen nie. G~+7 + BA of Kelpak'" behandelings het geen effek op boomgroei of varsmassa-verspreiding gehad nie. Groeistimulasie deur GA3 en/of Aldicarb kan lei tot vinniger vul van spasie, en hoër en vroeër oeste, maar verdere studies is nodig om die resultate te bevestig. Onvoldoende koolhidraat- en stikstofreserwes word dikwels gekoppel aan swak vestigingsprestasie van kwekerybome. Die effek van boomgrootte by planttyd en verskillende tophoogtes op vroeë groei in die veld is geëvalueer; die fisiese en chemiese profiel van lang ongetopte kwekerybome is ook gekwantifiseer. Betekenisvolle korrelasies is gevind tussen die aanvanklike stamdeursnit en en finale stamdeursnit en tussen aanvanklike boomhoogte en finale boomhoogte aan die einde van die eerste groeiseisoen. Stamdeursnit-toenarne is betekenisvol verminder in getopte bome relatief tot ongetopte bome. Wortels het uit ongeveer 22% en die bogrondse porsie ongeveer 78% van die totale droë massa bestaan. Wortels het bykans altyd hoër konsentrasies koolhidrate- en stikstofreserwes bevat. Die bogrondse gedeeltes, wat ook 'n hoër proporsie van die totale droë massa bevat, het meer as twee derdes van die totale koolhidraat en stikstofreserwes. Die top van kwekerybome op 60 cm bo die grond sal lei tot 'n verlies van 33 tot 37% droë massa, 29 tot 33% koolhidrate en 37 tot 46% stikstof. Dus, die plant van groot, ongetopte kwekerybome sal die aanvanklike boomgroei in die boord verbeter. Die gebruik van goedvertakte kwekerybome by planttyd kan die tyd tot komrnersieële vrugteproduksie verkort. Sitrus-kwekerybome gee nie voldoende laterale vertakking in die kwekery of in die boord nie. Twee studies op pas-aangeplante bome (een en vyf maande na plant) is uitgevoer om verskillende tegnieke om laterale lootgroei te stimuleer te evalueer, nl. Promalin® (G~+7 + BA) (teen 1000 of 2000 mg/I) en/of blaarverwydering, en die maak van kerfies op individuele knoppe of op bome as geheel. In die eerste studie, op die een-maand-oue bome, is geen betekenisvolle resultate verkry nie. In die tweede studie het kerfies en ringelering die hoeveelheid en lengte van laterale takke betekenisvol vermeerder, maar kerfies was meer effektief. Die bome moet egter blykbaar goed gevestig wees voor dit reageer. In jong, nie-draende bome word baie energie gebruik in die blomproses en dit lei tot die inhibisie van vegetatiewe groei. Gibberelliensuur (GA3 ) en 'n swaar mineralolie (Bac-oil) wat individueel of in kombinasie toegedien is tydens die vroeë winter is geëvalueer as 'n tegniek om blomvlakke in jong nie-draende sitrusbome te verminder. GA3 en minerale olie individueel of in kombinasie, is gespuit vanaf April tot Julie op die bome as geheel. GA3 en minerale olie toegedien individueel of in kombinasie laat in Mei tot Junie het blomvlakke verminder. GA3 toegedien in middel April het 'n minimale effek gehad. Die beste reaksie op GA3 het saamgeval met 'n betekenisvolle vermindering in die bot van knoppe. Alhoewel die optimum tyd van toediening rondom Mei tot Julie is, mag hierdie tyd wissel van jaar tot jaar afhangende van die effek van heersende temperature en ander klimaatstoestande. Die wintertoediening van GA3, spesifiek en moontlik in kombinase met minerale olie om blomvlakke en vroeë vegetatiewe groei te verminder kan kommersieel gebruik word. Die reaksie op hierdie behandelings mag egter drasties wissel van seisoen tot seisoen. Die effek van die tyd van toediening en konsentrasie van 2,4- dichlorofenoksipropioonsuur (2,4-DP) en 1-naftaleenasynsuur (NAA) as potensiële vruguitdunagente om vrugset kort na blom totaal te verminder en om vegetatiewe groei te verbeter, is geëvalueer oor 'n twee-jaarperiode. 2,4-DP teen 150 en 300 mg/l en NAA teen 200 en 400 mg/l is gespuit op 2- en 4-jaaroue 'Mihowase' Satsuma, en ook op 2-jaaroue 'Marisoi', 'Nules' en 'Oroval' Clementines op twee tye (laat Oktober en vroeg November). Die hoër konsentrasies van 2,4-DP en NAA het oor die algemeen nie gelei tot 'n verhoging in vrugafsnoering in die eeste jaar nie. Met 2,4- DP het die hoër konsentrasie gelei tot strawwer uitdunning in die tweede jaar. 2,4-DP en NAA kan as potensiële vruguitdunagente op jong, nie-draende bome gebruik word.
284

Studies on the control of russeting in apple fruit with plant growth regulators

Taylor, David Robert January 1988 (has links)
No description available.
285

Parkia biglobosa (Jasq.) benth. in Nigeria : a resource assessment

Oni, Peter I. January 1997 (has links)
Parkid higlohosa, an important indigenous fruit tree of West Affican Sudanian woodland, was studied with respect to natural population distribution and structure, regeneration, reproductive biology and phytosociology in Nigeria. As relevant background, a comprehensive range-wide monographic account of the species was assembled. An ecological survey covering the range of Parkia in Nigeria was undertaken between 1994-1995. The survey involved four ecological zones ranging from derived to Sudan/Sahel zone transition. In each ecological zone there were two sample sites within each of which there were two land use types. The survey showed that nearest mature con-specific neighbour distance and corresponding stocking for all individuals ý: 10 cm dbh ranged from 25.5 m and 15 tree ha-I in the north down to 91.5 m and I tree ha-I in the south. A gradual increase in stocking from the lowland forest zone boundary to the Sudan savanna was observed. Parkia populations are significantly more concentrated in cultivated fields than in less intensively used areas of the bush fallow. Natural regeneration in Parkia in Nigeria was sparse overall - 9.80 individuals ha-I and coppice shoot regeneration was the main form. Bush fallow conditions favour more regeneration than intense cultivation, and to the south there is more regeneration than in the north. Tree morphological appraisal showed that there tended to be taller trees in the south of the Nigerian range (with a moister climate) but with smaller diameter than in the north. A broader crown diameter typified populations in the northern part of Nigeria range compared with the south. Branching height ranged from 1.7 m in the north to 3.9 m in the south. The tree rarely branched below Im anywhere. Two was the most frequent number of primary branches. Individuals with more than two primary branches per tree occur more frequently in the north of the range. For all morphological parameters except the number of primary branches a significant land use effect was detected. In the survey 136 associated woody species were recorded. More woody tree species were associated with Parkia biglobosa in the south than in the north of its range in Nigeria. A reproductive cycle of 135 days was observed at Saki, Nigeria. Capitulum abortion rate was more than 30% and not related to the tree diameter or crown position. Capitulum, podding efficiency was about 67%. Open pollinated capitula had the highest number of pods per treatment. Parkid displays some degree of self-compatibility. Capitula located >5 m above the ground are more likely to be pollinated than those below.
286

Variação morfológica e química dos frutos na escolha dos animais frugívoros da Mata Atlântica /

Cazetta, Eliana. January 2008 (has links)
Resumo: As características dos frutos como morfologia e química têm sido tradicionalmente explicadas como resultado da seleção dos dispersores de sementes. Mas a importância dos frugívoros em moldar as características dos frutos tem sido recentemente questionada sob diferentes perspectivas. Alguns estudos sugerem que outras interações podem simultaneamente atuar sobre a evolução das características dos frutos. Muitos organismos atuam como predadores de sementes e seus efeitos precisam ser considerados. Desta maneira, as plantas enfrentam um dilema evolutivo entre atração aos legítimos dispersores de sementes e defesa contra predadores e patógenos. Neste estudo, primeiramente nós avaliamos as características dos frutos relacionadas com atração e defesa em uma ampla amostra de frutos da Mata Atlântica, da Ilha do Cardoso, São Paulo, Brasil. Posteriormente, nós testamos como algumas características específicas influenciam o consumo pelas aves frugívoras. Nós observamos que as características morfológicas e químicas dos frutos apresentam sinal filogenético e em geral padrões independentes de co-variação. Ao contrário, as cores e os contrates dos frutos não apresentam sinal filogenético e frutos mais saturados são ricos em lipídeos e energia mas pobres em carboidratos. Portanto, nós sugerimos que o grau de saturação da cor pode indicar a qualidade nutricional dos frutos. As aves detectaram consistentemente frutos com maior contraste cromático do que o contraste acromático. Além disso, as aves frugívoras selecionam frutos ricos em lipídeos e energia e pobres em compostos secundários. Nós concluímos que a preferência das aves por determinadas características dos frutos não afeta necessariamente a evolução das mesmas, uma vez que, para isso ocorrer é necessário que as aves selecionem entre indivíduos... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Fruit characteristics such as morphology and chemistry have traditionally been explained as the result of adaptations to their seed dispersers. But the importance of frugivores in shaping fruit traits has now been questioned from a number of perspectives. Some studies suggested that other interactions simultaneously shape the evolution of fruit traits. Many organisms act as seed predators and their effects must be taken into account. Therefore, plants are faced with an evolutionary dilemma between attraction to legitimate seed dispersers and defense against seed predators and pathogens. In this study we focused on fruit traits related to attractiveness and defense. We first evaluated how fruit characteristics interact in a broad sample of Atlantic rainforest species, at Cardoso Island, São Paulo, Brazil, after accounting for phylogeny. We then evaluated specific fruit characteristics to test whether they influence consumption by birds. We found that morphological and nutritional traits showed phylogenetic signal and in general independent patterns of covariation. On the contrary, fruit color and contrast did not present phylogenetic signal and saturated fruits are rich in energy and lipids, and poor in carbohydrates. Thus we suggest that saturated fruits may indicate fruit quality. Birds consistently detected fruits with higher chromatic contrasts rather than achromatic ones. Frugivorous birds also selected lipid and energyrich fruits and fruits low defended by secondary compounds. We conclude that in spite of bird's preferences these processes do not operate on the evolution of fruit traits, since this requires birds to differentiate between plant individual of the same and not different species. Therefore, in our study we observed that fruit traits are in general weak associate, with the exception of fruit color, that may indicate fruit adaptation to frugivores. / Orientador: Mauro Galetti / Coorientador: Marco Aurélio Pizo Ferreira / Banca: Pedro Jordano / Banca: Wesley Rodrigues Silva / Banca: Marco Aurélio Ribeiro de Mello / Banca: Silvana Buzato / Doutor
287

An experimental study of group selection using Drosphila melanogaster

Moy, F. H. January 1985 (has links)
No description available.
288

A transcriptome analysis of apple (Malus x domestica Borkh.) cv ‘golden delicious’ fruit during fruit growth and development

Chikwambi, Zedias January 2013 (has links)
Philosophiae Doctor - PhD / The growth and development of apple (Malus x domestica Borkh.) fruit occurs over a period of about 150 days after anthesis to full ripeness. During this period morphological and physiological changes occur defining fruit quality. These changes are a result of spatial and temporal patterns of gene expression during fruit development as regulated by environmental, genetic and environmental-by-genetic factors. A number of previous studies partially characterised the transcriptomes of apple leaf, fruit pulp, whole fruit, and peel plus pulp tissues, using cDNA micro arrays and other PCR based technologies. These studies, however, remain limited in throughput and specificity for transcripts of low abundance. Hence, the aim of this project was to apply a high throughput technique to characterise the full mRNA transcriptome of the ‘Golden Delicious’ fruit peels and pulp tissues in order to understand the molecular mechanisms underlying the morphophysiological changes that occur during fruit development.
289

Three species of orchard mites and their predators on apple trees in the southern Okanagan valley of British Columbia, and the effect of three insecticides on this complex

Chant, Donald Alfred January 1952 (has links)
The behaviour of the orchard mites Bryobia pretiosa (Koch) and Metatetranychus ulmi (Koch) and four species of predators was investigated both on unsprayed and on sprayed apple trees. On unsprayed trees the host mites were found to be most abundant on the east sides; no consistent directional preference was found for the predacious species. Small apple leaves supported the same number of M. ulmi per unit area as large leaves, but more mites of the genus Tetranychus. On unsprayed trees a negative correlation between the total number of predators and the number of host mites was recorded. In abandoned orchards the predators were capable of controlling the host mites and maintaining them at a level below that of economic significance. Each of the insecticides DDT, Parathion, and lead arsenate, was found to be very toxic to all species of predators recorded, and thus hindered or entirely prevented natural control of the host mites. In every instance lead arsenate and DDT produced an increase in the population of B. pretiosa, this effect being partially chemical and partially due to a lack of predators on the sprayed trees. Lead arsenate caused an increase in the population of M. ulmi whereas DDT reduced it to a slight extent. Under arid conditions Parathion caused an increase in the population of B.pretiosa; under less arid conditions the mite was eliminated. Parathion had no effect on M. ulmi in a commercial orchard while, in the same orchard, it caused a great increase in Tetranychus spp. The latter species were reduced by DDT in the commercial orchard. / Science, Faculty of / Zoology, Department of / Graduate
290

The Centrifugal separation of apple cell serum

Coltart, Michael Logan January 1974 (has links)
Factors affecting the centrifugal separation of apple parenchyma cell serum were investigated for three important cultivars from the Okanagan Valley of British Columbia; Mcintosh, Red Delicious, and Winesap. The factors studied included cultivar, maturity, maceration treatment, and centrifugation time and speed. Observations included yield of cell serum, relative serum clarity, pulp and serum viscometric properties, alcohol insoluble solids, soluble solids, serum pH, particle size and tissue firmness. The pulp viscometric property, viscosity at a shear rate of 100 sec⁻¹, was the observation which primarily influenced juice yields. The increased separation obtained for Mcintosh > Red Delicious > Winesap was attributed to pulp viscosity values. Relative serum clarity was influenced by serum soluble solids when centrifugation time was constant at six minutes or by the serum pH and pulp viscosity at maturity one (0 storage). Increased centrifugation speed and time markedly improved the yield of cell serum for the factors evaluated. Maceration treatments reduced the average particle diameter from 330 μm to 229 μm and the pulp viscosity values. At 5,500 and 8,000 rpm, higher yields were obtained when the particle size was small. At 10,500 rpm or 14,500 rpm, higher serum yields were obtained with larger particle sizes. Consideration of the particle size (> 100 μm) and shape (non-spherical), along with sedimentation theory indicated the separation followed Newton's Law. The high yields obtained with the larger particle size at high rpm confirmed a low drag force coefficient (C[sub D] = .5). Although a slight reduction in particle size and viscosity was observed when parenchyma tissue was subjected to ultrasonic vibration, no improvement was obtained in serum yield or clarity. The centrifugal separation of apple parenchyma cell serum was shown to be feasible. The efficiency of the separation improved as pulp viscosity decreased and speed or time of centrifugation increased. The tissue particle size evaluated was of secondary importance for the separations observed. / Land and Food Systems, Faculty of / Graduate

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