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Regulation of branching by phytochrome B and PPFD in Arabidopsis thalianaChou, Nan-yen 10 October 2008 (has links)
The branching or tillering of crops is an important agronomic trait with a major
impact on yield. Maintaining an appropriate number of branches allows the plant to use
limited light resources and to produce biomass or yield more effectively. The branching
process includes the initiation of the axillary meristem leading to bud formation and the
further outgrowth of the axillary buds. Phytohormones, including cytokinins and auxin,
are known to play major roles in regulating axillary bud outgrowth.
Light signals, including light quantity and light quality, are among the most
important factors regulating plant growth and are perceived by the action of specialized
photoreceptors, including phytochromes. Phytochromes sense red (R) and far-red (FR)
light and allow some plants to perceive and respond to competing neighbors by evoking
the shade avoidance syndrome (SAS). One component of the SAS is inhibition of
branching. Phytochrome B (phyB) is especially important in sensing shade signals and
loss of phyB function results in a constitutive shade avoidance phenotype, including
reduced branching. While it has been anecdotally reported that phyB-deficient
Arabidopsis branches less than wild type, a detailed study of the defects in the process is
lacking. In this research, the interactions between light signals, phytochromes and phytohormones in the regulation of branching were assessed using an integrated
physiological, molecular and genetic approach.
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E-budgivning : om och hur budgivning via Internet påverkar bostadsmarknaden i termer av utbudspris och överlåtelseprisvon Essen, Emma January 2006 (has links)
Den här uppsatsen studerar om och hur tjänsten e-bud, budgivning via Internet, påverkar utbudspriset och överlåtelsepriset på småhus i Sverige. Köpare och säljare måste söka på bostadsmarknaden för att finna information om utbudspris och överlåtelsepris i förhållande till område och kvalitet. Detta är en process som den moderna utvecklingen av informationsteknologin kan påverka förutsättningarna för. Överlåtelsepriset bestäms i regel av en budgivning mellan köpare och säljare medan utbudspriset antas vara säljaren reservationspris. Detta kan informationsteknologin också inverka på. De huvudsakliga slutsatserna i uppsatsen är att e-bud förenklar sökprocessen, vilket resulterar i ett högre överlåtelsepris jämfört med konventionell budgivning samt att utbudspriset har betydelse för överlåtelsepriset men inte för den procentuella vinsten utöver utbudspriset. Utbudspriset på småhus sålda via e-bud visar därmed säljarens reservationspris.
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Modelling Biennial Bearing in Apple TreesPellerin, Brian 18 August 2011 (has links)
Many commercially grown apple cultivars have a biennial cropping habit, producing many small fruit in one year and few or none in the following year. The production of fruits is known to inhibit flower initiation for the following year. This undesirable trait is frequently managed by removing (thinning) some flowers or young fruit in years of heavy flowering which improves the size of remaining fruits, but does not reliably improve flowering in the following year. The effect of thinning on flower initiation is not well understood. Two mathematical models are developed describing the relationship between flowering in one year and the next. The first models the effects of thinning on return bloom and attempts to define maximum repeatable flower number. The second models how proximity of growing points may impact biennial bearing and maximum annual flower number. This second model may be useful to advance research into biennial bearing in apple.
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Agronomic, physiological and genetic studies on a dwarf mutant of cocoa (Theobroma cacao L.)Eremas Tade Unknown Date (has links)
Cocoa (Theobroma cacao L.) is an important cash crop in the coastal areas of Papua New Guinea (PNG). In 2000, a mutant cocoa genotype MJ 12-226, with abnormal growth characteristics was identified at the Cocoa and Coconut Institute of PNG. The mutant, found among progenies of the cross Scavina 12 x Nanay 149, was characterized by dwarfing, small and narrow leaves, a small root system and strong branching habit. This study was designed to improve the understanding of the dwarf cocoa mutant and identify its relevance to future cocoa farming. The specific objectives are to investigate the feasibility of using a dwarf mutant of cocoa as a commercial rootstock for various hybrid cocoa clones, to study the genetics of this dwarf mutant and the role of plant hormones in differentiating this mutant from the normal phenotype. This study was carried out at the Cocoa and Coconut Institute of PNG, Rabaul, Papua New Guinea, and at the University of Queensland, Gatton Campus, Australia. The comparative study of mutant and normal cocoa seedlings revealed distinct vegetative differences between the two genotypes at the nursery stage. The largest effects of the mutant genotype are on stem elongation, short internodes, multiple stems, root growth and leaf growth. The agronomic results indicated that the mutant rootstock significantly reduced tree vigour at least in the early years. When used as a rootstock, the mutant had a significant dwarfing effect on scion growth of cocoa clones in the nursery and persisted in the field 12 months after planting. After that, the cocoa clones grafted on mutant rootstock reverted to normal growth. It was postulated that the accumulation of endogenous growth substances and cambial activity between the scion (normal) and the rootstock overcame the dwarfing effect of the mutant genotype. Yield and vegetative data collection from this trial ceased on May 2006 and recommenced in May 2007 to allow trees to recover from heavy canopy pruning due to cocoa pod borer attack. This resulted in one year loss of yield and vegetative data from this experiment. The first two years’ yield data indicated no significant differences between mutant, normal segregants and commercial rootstocks. However, cocoa clones bud grafted on these mutant rootstocks produced significantly greater yield at higher planting density compared with lower densities and this was sustained for two years. However, it might be expected that competition among cocoa trees would increase with increased size of trees, favouring low density planting and reducing the differential performance of the trees under high density planting with time. The major advantages of reducing tree vigour are to improve the harvest index, ease of harvesting, pruning and overall management of the trees. The continuation of this study to collect mature tree yield data (from fifth to eighth years) would confirm these results. This work has also demonstrated for the first time that cocoa clones grafted on mutant rootstock can produce similar yields to clones grafted on normal or commercial rootstocks. Moreover, this study has also established that cocoa clones derived from orthotropic scions can yield the same as plagiotropic scions when grafted on to either mutant or normal rootstocks. Therefore, it is proposed that mutant rootstocks and orthtropic scions should also be considered for future use in cocoa farming. The strong branching habit and dwarfing stature of the mutant suggested that the mutation affects the quantity or the balance of plant growth hormones, or both. The effect of exogenously applied gibberellic acid (GA3) on developmental processes in dwarf mutant and normal cocoa seedlings was studied. Both dwarf mutant and normal one month old cocoa seedlings responded to gibberellic acid (GA3) by accelerated longitudinal growth, especially seedling height. Paclobutrazol (PBZ) applied to normal cocoa seedlings altered the growth so that they almost resembled the mutant phenotype. It was postulated that PBZ prevented GA biosynthesis in the normal cocoa seedlings and therefore decreased bioactive auxin (IAA) which, in turn, then promoted lateral shoot growth; PBZ also slightly retarded plant growth. Synthetic auxin (IBA/NAA) significantly inhibited lateral bud sprouting and growth of intact, decapitated and nodal segments of mutant and normal cocoa seedlings compared with control and those treated with IAA. It appears that the mutant and normal cocoa genotypes have a similar capacity to metabolize IAA and this capacity was much greater than for synthetic auxins. The results suggested that auxin levels in the mutant seedlings were probably limiting, and therefore affected biosynthesis of gibberellic acid thus resulting in the dwarfing characteristics of the mutant cocoa genotype. However, analysis of endogenous IAA and GA1 levels at four months old did not reveal differences between the mutant and normal seedlings. The present genetic studies which included backcrossing, test crossing and selfing of F1 progenies confirmed earlier work on the mutant and showed that the mutant was probably heterozygous (Dd). The allele (DD) in mutant cocoa is probably lethal in nature because the phenotype of the homozygote was not observed amongst the mutant progenies. Mutant segregants were obtained in a 1:1 ratio only when the mutant clone was used as the female; however, when the mutant was used as male, very few mutant segregants were obtained. This suggested selective pollen viability (pollen grains carrying the D allele are nonviable) or an incompatible reaction between pollen tubes (D carrying pollen) and style or ovule. The selfing and test-crosses of F1 progenies resulted in deviation from the expected 3:1 segregation ratio to a 1:1 ratio.
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FUNCTIONAL ANALYSIS OF GENES CONTROLLING PRODUCTION OF THE LATERAL BRANCHING INHIBITOR IN PEATanya Brcich Unknown Date (has links)
This thesis describes a molecular-based study undertaken to analyse the expression of the RAMOSUS1 (RMS1) and RAMOSUS5 (RMS5) genes in pea (Pisum sativum). Both genes encode carotenoid cleavage dioxygenase (CCD) enzymes that are together proposed to control the synthesis of an inhibitor of bud outgrowth termed SMS (Shoot Multiplication Signal). SMS was recently identified as strigolactone. Expression analyses of RMS1 presented here have built upon earlier experiments which demonstrate it to be a highly regulated transcript. RMS1 mRNA levels are known to be rapidly decreased following removal of the shoot apex but are subsequently restored to that of intact plants by auxin (indole-3-acetic acid or IAA). This regulatory mechanism is retained in all five ramosus mutants tested to date. Together with physiological data, this indicates RMS1, and therefore SMS, are required in IAA-mediated suppression of bud outgrowth. Another significant aspect of RMS1 regulation identified in previous studies involves a graft-transmissible, long-distance feedback signal that moves from shoot to root. This feedback regulation is dependent on the RMS2 gene and enhances RMS1 expression levels. Prior to the cloning of RMS5 and its discovery as a second CCD enzyme in the RMS network, reciprocal grafting studies with the rms mutants indicated RMS5 may act in the same pathway as RMS1 to produce SMS. Multiple studies presented here demonstrate that these two CCD genes are expressed in similar tissues and are regulated by the same signals, specifically IAA and the RMS2-dependent feedback signal. Like RMS1, the RMS5 gene also retains its IAA response in the rms mutants. However, RMS5 is generally less responsive to changes in IAA and RMS2-dependent feedback, as it exhibits smaller fluctuations than RMS1 in its expression levels. Together these findings support a general view that RMS1 is more likely to control a rate-limiting step in SMS synthesis. A previous study indicated that RMS1 expression may be up-regulated by IAA through a posttranscriptional mechanism. This thesis sought to more closely examine the RMS1 and RMS5 IAA response by separately observing the effect of IAA on subsequent transcription. New transcripts, termed heterogenous nuclear RNAs (hnRNAs), were relatively quantified in parallel with existing mRNAs in the steady-state cytoplasmic pool. The experiments conducted here provide further evidence that IAA may act post-transcriptionally to stabilise RMS1 mRNA because the changes in hnRNA are not proportional to the changes in mRNA following IAA-modifying treatments. IAA may still function to induce transcription of RMS1, but this does not appear to be a significant mechanism by which IAA regulates RMS1 expression. In contrast, the IAA induction of RMS5 occurs predominantly via new transcription and RMS5 either lacks or is not as strongly subjected to the IAA-mediated mRNA stabilisation mechanism proposed for RMS1. Initial studies described in this thesis also suggest that IAA could act to regulate the expression of the Arabidopsis orthologues MORE AXILLARY BRANCHING (MAX) genes via a post-transcriptional mechanism. Analyses of MAX hnRNA and mRNA levels in Arabidopsis to date indicate it is the RMS5 orthologue MAX3 which exhibits an IAA response most like RMS1. Additional studies into the regulation of RMS1 and RMS5 presented in this thesis provide further insights into the molecular mechanisms controlling their expression levels. In vitro experiments with the translation inhibitor cycloheximide demonstrate that RMS5 expression levels are increased when protein synthesis is reduced, as previously shown for RMS1. Relative quantification of RMS1 and RMS5 hnRNA levels further demonstrate that the induction by cycloheximide is due primarily to an increase in new transcription, indicating that RMS1 and RMS5 are negatively regulated by a rapidly turned-over transcriptional repressor. Tissue specific effects on RMS1 expression were also observed which are consistent with a protein degradation function of the RMS4 F-box in the shoot. This thesis provides further evidence to suggest that SMS acts in concert with IAA to inhibit the sustained outgrowth of axillary buds. RMS1 and RMS5 expression levels are not regulated by a hypothetical fast decapitation signal which is proposed to cause the initial bud outgrowth occurring prior to decapitation-induced IAA depletion. RMS1, RMS5 and SMS are therefore unlikely to control the initial exit of buds from dormancy to an intermediate transition state. Studies here also suggest that enhanced shoot auxin transport and cytokinin biosynthesis are associated with axillary bud outgrowth because the rms mutants contain elevated shoot expression levels of a gene encoding the auxin efflux carrier PIN1 and two genes controlling cytokinin biosynthesis. Several approaches described in this study were used to characterise the RMS1 and RMS5 proteins. Anti-peptide antibodies were generated against both proteins and the results obtained show that although the antibodies are likely to recognise the full-length proteins, further work is required to effectively detect RMS1 and RMS5 in plant tissues via western blotting. Preliminary in situ immunolocalisation results indicate the RMS1 and RMS5 proteins are localised to the vasculature, consistent with gene expression analyses.
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Validação temporal e tissular de genes envolvidos no desenvolvimento de botão floral de algodoeiroPINHEIRO, Morganna Pollynne Nóbrega 28 May 2015 (has links)
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Previous issue date: 2015-05-28 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / A growing number of studies reports the identification and characterization of genes associated with flower bud and the isolation of its regulatory regions. These strands are helping to unravel a number of issues concerning the regulation and cellular interactions, thus generating a great impact on improving various plant species. In cotton (Gossypium hirsutum) these studies have contributed substantially in obtaining of genetically modified GM plants, holders of genes for resistance to herbicides and lepidopteran, and are becoming the possibility of increasing the control efficiency against target pests that act directly in floral structures and / or even enhance the expression of the coloring effect of the fibers. Different techniques are available for functional genomics analysis, among the most adopted is the construction of expressed sequence tags (ESTs) libraries that allows to identify which RNAs are expressed in an organism at a given time. Using this methodology in a previous study, were characterized by in silico analyzes genes involved in reproductive functions of cotton, some of whom expressed in male and female gametophytes. At that moment, from RT-PCR assays and qRT-PCR, six genes (GhASH, GhFIB010, GhGLUC, GhMYB, GhOVU and GhUDP) were investigated for the temporal expression during ontogeny flower bud, at stages 2-4 6-8, 10, 12, 14-16, and 18-20 mm. All of the genes investigated were active in floral buds of different sizes and in different expression levels, however, the highest level observed was 10 mm, except for gene GhASH with the highest expression in 10 to 16 mm. In these stages the cotton bud is in intense cellular activity including reduced cell wall formation of the complete embryonic sac, appearance and degeneration of the antipodes suggesting that these genes that may be involved in the formation and development or ovules, pollen, pollen tube, as well as on fibers. The gene was GhASH which also had the highest level of expression in all stages compared to other genes. Due to the regulation of these genes involved precursor steps, prior to anthesis and possibly runs through the final process of maturation, we proceeded further a study of tissue expression in organs flowering cotton (bracts, sepals, petals, ovules, anthers and fibers with 8, 10 and 18 DPA) to understand the interrelationships of the genes involved in the reproductive phase and its performance during development. It was found that all genes showed equivalent expression with its features, described in the databases. Analyses of gene activity for genes GhASH, GhOVU and GhGLUC proposed performances in training and / or development of all floral organs especially in pollen grains, pollen tube and anthers. For genes involved in fiber GhMYB, GhFIB010, GhUDP expression was observed for all studied growth stage, suggesting that are directly involved in elongation phase of the fibers, this phase has been widely investigated since the length of the cotton fiber is a key feature in determining the quality and yield. Additional studies to functional characterization of promising genes and isolation of their regions upstream become necessary in order to contribute to the progress and molecular breeding of this oilseed. / É crescente o número de pesquisas que reportam a identificação e caracterização de genes associados ao botão floral, bem como no isolamento de suas regiões regulatórias. Estas vertentes vêm auxiliando na elucidação de várias questões relativas à regulação e das interações celulares, gerando assim um grande impacto no melhoramento de várias espécies vegetais. Em algodão (Gossypium hirsutum) estes estudos têm contribuido substancialmente na obtenção de plantas geneticamente modificadas (GM), detentoras de genes para resistência a herbicidas e lepidópteros, e reveste-se na possibilidade de aumentar a eficiência de controle contra pragas alvo que atuam diretamente em estruturas florais e/ou ainda, potencializar o efeito de expressão na coloração das fibras. Diferentes técnicas estão disponíveis para a análise de genômica funcional, entre as mais adotadas está a construção de bibliotecas de curtas sequêcias expressas (ESTs) que permite identificar quais RNAs mensageiros estão sendo expressos num organismo em um determinado momento. Com o uso desta metodologia em estudo anterior, foram caracterizados por análises in silico genes envolvidos em funções reprodutivas do algodoeiro, alguns dos quais expressos nos gametófitos masculino e feminino. Nesse momento, a partir de ensaios de RT-PCR e qRT-PCR, seis genes (GhASH, GhFIB010, GhGLUC, GhMYB, GhOVU e GhUDP) foram investigados quanto à expressão temporal durante a ontogenia do botão floral, nos estádios de 2-4, 6-8, 10, 12, 14-16 e 18-20 mm. Todos os genes investigados apresentaram atividade nos diferentes tamanhos dos botões florais e com níveis diferenciados de expressão, contudo, o maior nível foi observado no tamanho de 10 mm, com exceção do gene GhASH que apresentou maior expressão nos botões de 10 a 16 mm. Nestes estádios o botão encontra-se em atividade celular intensa incluindo redução da parede celular, formação dos sacos embrionários completos, surgimento e degeneração das antípodas, sugerindo que esses genes podem estar envolvidos na formação e ou desenvolvimento de óvulos, grãos de pólen, tubo polínico, como também em fibras. O gene GhASH também apresentou o maior nível de expressão em todos os estádios do botão floral quando comparado aos demais genes. Em função da regulação desses genes envolverem etapas precursoras, que antecedem a antese e que, possivelmente perpassa o processo final de maturação, procedeu-se adicionalmente um estudo de expressão tissular em órgãos floríferos do algodão (brácteas, sépalas, pétalas, óvulos, anteras e fibras com 8, 10 e 18 DPA) de modo a entender as interrelações dos genes envolvidos na fase reprodutiva e sua atuação durante o desenvolvimento. Verificou-se que todos os genes apresentaram expressão equivalente com suas funcionalidades descritas nos bancos de dados. As análises da atividade gênica para os genes GhASH, GhOVU e GhGLUC propuseram atuações na formação e/ou desenvolvimento de todos os órgãos florais sobretudo em grãos de pólen, tubo polínico e anteras. Para os genes envolvidos nas fibras, GhMYB, GhFIB010, GhUDP, a expressão foi observada para todas as três fases fenológicas estudadas, sugerindo assim que estejam envolvidos diretamente na fase de elongação das fibras, fase que tem sido bastante investigada, uma vez que o comprimento das fibras de algodão é uma característica chave de determinação da qualidade e rendimento. Estudos adicionais para caracterização funcional dos genes promissores e isolamento de suas regiões upstream tornam-se necessários a fim de contribuir com os avanços do melhoramento genético e molecular dessa oleaginosa.
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Belowground bud banks as regulators of grassland dynamicsDalgleish, Harmony J. January 1900 (has links)
Doctor of Philosophy / Department of Biology / David C. Hartnett / In perennial grasslands, the belowground population of meristems (the bud bank) plays a
fundamental role in local plant population structure and dynamics. I tested the “meristem
limitation hypothesis” prediction that bud banks increase along an increasing
precipitation/productivity gradient in North American grasslands. I sampled bud populations
quarterly at six sites across a 1,100 km gradient in central North America. Bud banks increased
with average annual precipitation, which explained 80% of variability in bud banks among sites.
Seasonal changes in grass bud banks were surprisingly similar across a 2.5-fold range in
precipitation and a 4-fold range of aboveground net primary productivity (ANPP). Secondly, I
tested the hypothesis that tallgrass prairie plants respond to increases in a limiting resource
(nitrogen) through demographic effects on the bud bank. I parameterized matrix models for
individual genets, considering each genet as a population of plant parts (buds and stems).
Nitrogen addition significantly impacted bud bank demography of both Sporobolus heterolepis
and Koeleria macrantha. In 2005, emergence from the bud bank and growth rates (λ) of the tiller
population were significantly higher in S. heterolepis genets that received nitrogen. In contrast, nitrogen addition decreased λ in K. macrantha. Both prospective and retrospective analyses indicated that bud bank dynamics are the key demographic processes driving genet responses to nutrient availability. Lastly, I tested the hypothesis that the effects of fire and grazing on plant species composition and ANPP are mediated principally through demographic effects on bud
banks. I found that plants respond to fire and grazing with altered rates of belowground bud
natality, bud emergence, and both short-term (fire cycle) and long-term changes in bud density.
The size of the bud bank is an excellent predictor of long-term ANPP, supporting my hypothesis
that ANPP is strongly regulated by belowground demographic processes. Meristem limitation
due to water or nutrient availability or management practices such as fire and grazing may
constrain grassland responses to inter-annual changes in resource availability. An important
consequence is that grasslands with a large bud bank may be the most responsive to future
climatic change or other phenomena such as nutrient enrichment, and may be most resistant to
exotic species invasions.
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Effect of shoot removal on bud fruitfulness and yield of Vitis vinifera cv. ‘Crimson Seedless’ in the Western CapeLinks, Johannes January 2014 (has links)
‘Crimson Seedless’ (Vitis vinifera L.) is an attractive, late season, red, seedless cultivar, which is currently a very popular table grape cultivar. It is one of the most planted cultivars in South Africa and third in terms of total area of table grape vineyards in production. Mature ‘Crimson Seedless’ grapes are characterized by outstanding eating quality, good flavour, firm and crisp berries. One of the key factors affecting the yield of table grape cultivars is bud fruitfulness. Low fruitfulness can have a significant effect on the yield of table grape cultivars and ‘Crimson Seedless’ is characterized by a fruitfulness problem. Summer pruning, such as the removal of shoots after harvesting grapes, is a cultivation practice widely used by some table grape producers in the Orange River region of South Africa. The first hypothesis of this study stated that the removal of shoots after harvest will increase the transmitted PAR through the canopy, increase carbohydrate reserve levels in canes and improve bud fruitfulness of ‘Crimson Seedless’. A second hypothesis of this study stated that the cut back of all main shoots and shoots developing from spurs to the nearest lateral shoot and the removal of all unproductive shoots after berry set will result in fruitful shoots the following season. The third and final hypothesis of this study stated that the removal of shoots after harvest and berry set will improve the yield and quality of Vitis vinifera cv. ‘Crimson Seedless’.
The study was conducted over three seasons (2010/11 to 2012/13) and aimed at investigating factors, including shoot removal, impacting bud fruitfulness of an 11-year-old commercial V. vinifera L. cv. ‘Crimson Seedless’ vineyard, grafted on ‘Ramsey’ (Vitis champinii) rootstocks in the Hex River Valley. The treatment design was a complete randomized design and involved five treatments, which included 33% shoot removal (S33) and 66% shoot removal (S66) after harvest, cutting of all main and lateral shoots developing from spurs to the nearest lateral shoot (LS), removal of all unproductive shoots (RSB) which was compared with the control, in which standard pruning practices were performed. The results obtained in this experiment showed that shoot removal after harvest and after berry set improves PAR transmission into the canopy, but there was no significant impact on bud fruitfulness. In addition, it was found that shoot removal reduced vegetative growth resulting in thinner canes that also led to the improvement in PAR transmission. Furthermore, bunch number per shoot in the LS treated vines was reduced when compared with S33 treated vines, illustrating that shoot removal at berry set can reduce bunch number per shoot due to defoliation after berry set. The significant decrease in bud burst in the S33 treatments compared with the control was expected due to less shoots, resulting in a reduction in cane mass during the 2010/11 season.
The significant effect of LS treatments after berry set on TSS and total red pigments compared with the S66 treatments and the control, respectively, clearly indicates that shoot removal after berry set improves grape colour. The positive effect of LS treatments on colour was supported by the significant improvement in class 4 bunches, representing an improvement in quality. Although shoot removal did not have a significant effect on the bunch mass per vine of ‘Crimson Seedless’, there was a significant reduction in total bunches for export and mass of the total export bunches in the LS treatments in the 2011/12 season.
A link between carbohydrate concentration in canes and bud fruitfulness was not found in this study, as S33 and S66 treatments did not have a significant effect on carbohydrate content in canes during the 2011/12 season. The question therefore arises whether the treatments applied during the growing seasons are worthwhile, because there was no significant impact on bud fruitfulness of Vitis vinifera L. cv. ‘Crimson Seedless’. This study illustrates that growers need to decide whether it is worthwhile to utilize labour for this practice and they must manage grapevines not only for the current seasons crop, but also for the next season and this can be accomplished by maintaining sufficient carbohydrates for fruitfulness and yield from season to season. / Dissertation (MInst Agrar)--University of Pretoria, 2014. / tm2015 / Plant Production and Soil Science / MInst Agrar / Unrestricted
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Den svenska budgivningsprocessen - misstankar och transparensNilsson, Sandra, Hjelm, Nina January 2018 (has links)
Vår studie behandlar lagrum, praxis och doktrin inom den svenska budgivningsprocessen. I Sverige är bud inte bindande och transparensen i systemet blir därmed av stor vikt. Att bud inte är bindande innebär att en potentiell köpare aldrig behöver stå fast vid sitt bud och säljare behöver heller aldrig sälja till ett visst pris. Svensk rätt begär formkrav för att bindande bostadsköp skall vara giltigt. Först när ett köpekontrakt är påskrivit har ett köp kommit till stånd, detta medför risker för budgivarna och komplikationer för mäklarens förpliktelser. För att upprätthålla transparensen inom bostadsmarknaden och minska på misstankar harmäklaren en skyldighet enligt lag att upprätta en anbudsförteckning över alla inkomna bud. Den oreglerade budgivningsprocessen öppnar upp för misstankar om fabricerade bud då anbudsförteckningens krav på identifikation är relativt låg och enbart den slutliga köparen får tillgång till den efter köpet slutförts. Trots avsaknaden av uttryckliga lagregler har mäklaren förpliktelser mot säljare och spekulanter och måste ta hänsyn till god fastighetsmäklarsed under budgivningsprocessen. / Our study discusses the statutes, case-law and jurisprudence applicable to the Swedishbidding process. In Sweden bids are not binding and the transparency of the system istherefore of great importance. The fact that bids are not binding means that a potential buyer never needs to stick to his bid and sellers never have to sell at a certain price. Swedish law requests formal requirements for binding house purchase to be valid. Only when a purchase contract is signed has a purchase been made, this entails risks to the bidders and complications for the broker's obligations. To maintain transparency in the housing market and reduce suspicions, the broker has a legal obligation to draw up a tender list of all bids received. The unregulated bidding process open up for suspicions of manufactured bids when the bid list's identification requirements are relatively low and only the final buyer will have access to it after the purchase has been completed. Despite the absence of explicit legal rules, the broker has obligations to sellers and prospective buyers and must adhere to sound estate agency practice during the bidding process.
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A Study of Rest Period, Hardiness, and Bud Development of the 'Concord' GrapeWeeks, Mervin Gayle 01 May 1977 (has links)
The length of the 'Concord' grape rest period was evaluated during 1974-75 and 1975-76. Cuttings were placed in a 25 C growth chamber every two weeks from October through April. Number of days to reach 50 percent full bud swell was plotted to determine rest completion. Seven years of weather data and full bloom dates of 'Concord' grapes from Prosser, Washington were statistically analyzed to give another estimate of rest completion. Rest was terminated after about 830 chill units.
During 1974-75 and 1975-76, T50 temperatures were determined every two weeks for both cambium and primary buds of 'Concord' grapes. The cambium ranged 2 to 10 C hardier than the primary buds. The T50 temperature pattern correlated with the minimum ambient air temperatures.
Cuttings, collected and placed in growth chambers, were analyzed for both optimum and base temperatures. Optimum bud growth and development occurred at 25 C. The base temperature of first noticeable bud development was approximately 4.4 C.
Bud phenological stages were followed both years and a standard set of pictures of representative stages was compiled. The growing degree hours (GDH) from end of rest to first bud swell through full bloom to maturity were determined.
A regression line was plotted between the various GDH requirements for the percent soluble solids acquired during the 1975 and 1976 seasons. The GDH accumulation and soluble solids were well correlated with an r2 value of 0.95 percent.
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