Since the first report of Verticillium wilt of potato in 1950, the disease has been considered to be of minor importance in South Africa. Between 1995 and 2000, however, Verticillium spp. were isolated from 146 samples of symptomatic potato plant material received from 13 of the 14 potato production areas in the country. Of 93 Verticillium isolates that were obtained, 60% were identified as V. dahliae and 8 % V. nigrescens. V. dahliae was present in nine of the regions and V. nigrescens in seven. Unidentified Verticillium species were isolated from six of the regions. Both V. dahliae and V. nigrescens were pathogenic to potato in vivo, with V. dahliae the more virulent of the two species. Ten South African potato cultivars, eight of which have recently been released, were evaluated over two seasons in a greenhouse for resistance to V. dahliae. The cultivars Aviva, BP1, Bravo, Buffelspoort, Caren, Hoevelder and Ropedi were classified as susceptible to Verticillium wilt, whereas Calibra, Dawn and Devlin were rated as very susceptible. No resistance or tolerance was evident. The efficacy of broccoli volatiles on in vitro mycelial growth of Verticillium dahliae, and the effect of incorporation of fresh and dry broccoli residues on the survival of microsclerotia of V. dahliae and infection of potato, were determined in the laboratory and greenhouse. Volatiles emanating from freshly harvested macerated broccoli leaves were inhibitory to mycelial growth of V. dahliae on medium. Fresh and dry residues incorporated into soil artificially infested with V. dahliae, significantly reduced the viability of microsclerotia of the pathogen and the rate of infection of potato plants. Dry residues were more effective than fresh residues in reducing the viability of sclerotia, but suppression of infection was independent of the state of the residues. / Dissertation (MSc (Plant Pathology))--University of Pretoria, 2005. / Microbiology and Plant Pathology / unrestricted

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As technology advances in all areas of society and industry, the technology used to produce one of life's essentials - food - is also improving. The majority of agriculture production in developed countries has gone from family farms to industrial operations. With the advent of large-scale farming, the automation of basic farming operations has increasingly made practical and economic sense. Broccoli, which is still harvested by hand, is one of the most expensive crops to produce. Investing in sensing technology that can provide detailed information about the location, maturity and viability of broccoli heads has the potential to produce great commercial benefits. This technology is also a prerequisite for developing an autonomous harvester that could select and harvest mature heads of broccoli. This thesis details the work done to develop a computer vision algorithm that has the ability to locate the broccoli head within an image of an entire broccoli plant and to distinguish between mature and immature broccoli heads. Locating the head involves the use of a Hough transform to find the leaf stems and, once the stems are found, the location and extent of the broccoli head can be ascertained with the use of contrast texture analysis at the intersection of the stems. A co-occurrence matrix is then produced of the head and statistical texture analysis is performed to determine the maturity of the broccoli head. The conceptual design of a selective autonomous broccoli harvester, as well as suggestions for further research, is also presented. / Master of Science

The effects of packaging treatments, post harvest cooling delay and storage duration on color, texture, ascorbic acid content, weight loss and glucosinolate retention in crown-cut heads of broccoli were studied. Oxygen and CO2 levels inside shrink wrap packages were also monitored. Shrink wrap packaging had a significant positive effect on hue angle (p<0.05). Packaging and post harvest cooling delay had no effect on hue difference and total color difference. While post harvest cooling delay had no effect on texture, crown-cut heads of broccoli stored in shrink wrap packaging retained firmness significantly better than ice packaged heads of broccoli (p<0.05). Ascorbic acid was retained better in broccoli held in shrink wrap packages and cooling delay had a significant negative influence on ascorbic acid content (p<0.05). Packaging and post harvest cooling delay had a significant positive effect on weight loss (p<0.05). Broccoli stored in shrink wrap film lost about 3.7% of original weight while ice packaging resulted in about 17.4% weight loss (p<0.05). No consistent trends were observed in the levels of O2 and CO2 inside shrink wrap packages. An important glucosinolate, glucoraphanin was retained significantly better in shrink wrapped heads (p<0.05). Between two cultivars, shelf life of cv.Gypsy was better than cv.Everest with respect to color, ascorbic acid retention and weight loss. But cv.Everest retained texture (firmness) better after 35 days of storage. Overall results indicate that shrink wrap packaging and shorter post harvest cooling delays protect quality of broccoli. / Master of Science

Respondents of the 1986 Broccoli Growers Survey grew an average of 6.2 acres of broccoli in Fall 1986; popular varieties were Green Valiant (87.5% of respondents), Packman and Emperor (62.5%). Less than 5% of tobacco land was converted to broccoli production by 62.5% of the growers. Before heading, 2.4 insecticidal sprays were applied for worms at $20.51/acre. During heading, 2.4 insecticidal sprays were applied for worms at $19.40/acre. Under normal growing conditions, a nine-day mean of 8.4 and a 15-day mean of 12.1 cabbage looper larvae/plant did not significantly reduce yield in the Spring and Fall respectively. However, means of 7.4 and 11.1 cabbage looper larvae/plant reduced yield (head weight) under drought conditions. Harvest date was not affected by the above cabbage looper levels. In Fall 1986, a reduction in yield occurred when plants had 50% or more defoliation and harvest date was significantly delayed at 100% defoliation. In the drought stressed Spring 1987 planting, a stimulation in yield occurred at 25% defoliation and 75% defoliation was needed to significantly reduce yield, but there was no difference in harvest date. The imported cabbageworm was the most abundant pest of broccoli in Montgomery Co., VA. Based on counts of all immature stages of the insects for three seasons, Packman and Southern Comet varieties were less preferred compared to Green Defender. Laboratory studies indicated that imported cabbageworm larvae developed faster to the fifth instar on Packman broccoli than those reared on Green Defender, Southern Comet or Emperor. Difference in amount consumed between varieties was not detected. Pupae reared on Southern Comet weighed significantly more than those reared on Packman. / M.S.

Li, Yuk Man. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2005. / Includes bibliographical references (leaves 121-132). / Abstracts in English and Chinese. / ACKNOWLEDGMENTS --- p.i / ABSTRACT --- p.ii / LIST OF ABBREVATIONS --- p.vii / TABLE OF CONTENTS --- p.x / Chapter Chapter 1 --- General Introduction / Chapter 1.1 --- Introduction --- p.1 / Chapter 1.2 --- Theories of aging --- p.2 / Chapter 1.2.1 --- Free radical theory of aging --- p.3 / Chapter 1.2.2 --- Free radicals reactions and their effects --- p.4 / Chapter 1.2.2.1 --- Lipid peroxidation --- p.6 / Chapter 1.2.2.2 --- Protein oxidation --- p.6 / Chapter 1.2.2.3 --- DNA oxidation --- p.8 / Chapter 1.2.2.4 --- Carbohydrate oxidation --- p.8 / Chapter 1.2.3 --- Antioxidant defense systems --- p.9 / Chapter 1.2.3.1 --- Superoxide dismutase (SOD) --- p.9 / Chapter 1.2.3.2 --- Catalase --- p.11 / Chapter 1.2.3.3 --- Glutathione peroxidase (GPx) and reductase --- p.11 / Chapter 1.3 --- Models on aging study --- p.12 / Chapter 1.3.1 --- Non-mammalian model systems --- p.12 / Chapter 1.3.1.1 --- History of Drosophila on longevity study --- p.14 / Chapter 1.3.1.2 --- Advantages of Drosophila model --- p.14 / Chapter 1.3.2 --- Mammalian model systems --- p.15 / Chapter 1.4 --- Antioxidant effects on aging process --- p.16 / Chapter 1.4.1 --- Antioxidant capacity of tea --- p.16 / Chapter 1.4.2 --- Antioxidant capacity of vegetables --- p.19 / Chapter 1.5 --- Dietary fat on longevity --- p.21 / Chapter Chapter 2 --- Anti-aging: Effects of Green Tea Catechins on Life Span and Antioxidant Enzymes of Drosophila melanogaster / Chapter 2.1 --- Introduction --- p.24 / Chapter 2.2 --- Gbjectives --- p.27 / Chapter 2.3 --- Materials and methods --- p.28 / Chapter 2.3.1 --- Materials --- p.28 / Chapter 2.3.2 --- Preparation of GTCs --- p.28 / Chapter 2.3.3 --- Feeding experiment --- p.30 / Chapter 2.3.3.1 --- Dose determination --- p.31 / Chapter 2.3.3.2 --- Paraquat treatment --- p.31 / Chapter 2.3.3.3 --- Hydrogen peroxide (H202) treatment --- p.33 / Chapter 2.3.3.4 --- Enzyme activity assay --- p.34 / Chapter 2.3.4 --- Enzyme analysis --- p.34 / Chapter 2.3.4.1 --- SOD activity --- p.34 / Chapter 2.3.4.2 --- Catalase activity --- p.35 / Chapter 2.3.4.3 --- Lipid hydorperoxies (LOOHs) formation --- p.36 / Chapter 2.3.4.4 --- Determination of protein concentration --- p.37 / Chapter 2.3.5 --- Semi-quantitative RT-PCR assay --- p.37 / Chapter 2.3.5.1 --- RNA isolation --- p.37 / Chapter 2.3.5.2 --- Primer sequences --- p.38 / Chapter 2.3.5.3 --- Reverse Transcriptase PCR --- p.40 / Chapter 2.3.6 --- Statistics --- p.40 / Chapter 2.4 --- Results --- p.42 / Chapter 2.4.1 --- Dose determination --- p.42 / Chapter 2.4.2 --- Paraquat treatment --- p.45 / Chapter 2.4.3 --- H202 treatment --- p.48 / Chapter 2.4.4 --- SOD activity --- p.51 / Chapter 2.4.5 --- Catalase activity --- p.51 / Chapter 2.4.6 --- LOOHs formation --- p.53 / Chapter 2.4.7 --- Semi-quantitative RT-PCR assay --- p.53 / Chapter 2.5 --- Discussion --- p.55 / Chapter Chapter 3 --- Anti-aging: Effects of Vegetable Extracts on Life Span and Antioxidant Enzymes of Drosophila melanogaster / Chapter 3.1 --- Introduction --- p.62 / Chapter 3.2 --- Objectives --- p.64 / Chapter 3.3 --- Materials and methods --- p.65 / Chapter 3.3.1 --- Materials --- p.65 / Chapter 3.3.2 --- Preparation of vegetables extracts --- p.65 / Chapter 3.3.3 --- Feeding experiment --- p.65 / Chapter 3.3.3.1 --- Dose determination --- p.66 / Chapter 3.3.3.2 --- Paraquat and hydrogen peroxide (H2O2) treatment --- p.67 / Chapter 3.3.4 --- Lipid hydroperoxide (LOOHs) formation --- p.67 / Chapter 3.3.5 --- Enzyme analysis --- p.67 / Chapter 3.3.6 --- Semi-quantitative RT-PCR assay --- p.67 / Chapter 3.3.7 --- Statistics --- p.68 / Chapter 3.4 --- Results --- p.69 / Chapter 3.4.1 --- Dose determination --- p.69 / Chapter 3.4.2 --- Antioxidant effect among different vegetables --- p.69 / Chapter 3.4.3 --- SOD activity --- p.76 / Chapter 3.4.4 --- Catalase activity --- p.76 / Chapter 3.4.5 --- LOOHs formation --- p.78 / Chapter 3.4.6 --- Semi-quantitative RT-PCR assay --- p.78 / Chapter 3.5 --- Discussion --- p.80 / Chapter Chapter 4 --- Anti-aging Activity of Greeen Tea Catechins and Broccoli Extracts in Drosophila melanogaster Fed a High Fat Diet / Chapter 4.1 --- Introduction --- p.85 / Chapter 4.2 --- Objectives --- p.87 / Chapter 4.3 --- Materials and methods --- p.88 / Chapter 4.3.1 --- Materials --- p.88 / Chapter 4.3.2 --- Preparation of free fatty acid --- p.88 / Chapter 4.3.3 --- Prepartion of GTCs and BEs --- p.89 / Chapter 4.3.4 --- Feeding experiment --- p.89 / Chapter 4.3.5 --- LOOHs formation --- p.90 / Chapter 4.3.6 --- Enzyme analysis --- p.91 / Chapter 4.3.7 --- Semi-quantitative RT-PCR assay --- p.91 / Chapter 4.3.8 --- Statistics --- p.91 / Chapter 4.4 --- Results --- p.92 / Chapter 4.4.1 --- Dose determination --- p.92 / Chapter 4.4.2 --- Effects of GTCs or BEs on life span with lard consumption --- p.95 / Chapter 4.4.3 --- LOOHs formation --- p.101 / Chapter 4.4.4 --- SOD activity --- p.103 / Chapter 4.4.5 --- Catalase activity --- p.107 / Chapter 4.4.6 --- Semi-quantitative RT-PCR assay --- p.110 / Chapter 4.5 --- Discussion --- p.112 / References --- p.121

Made available in DSpace on 2016-04-28T14:58:37Z (GMT). No. of bitstreams: 1 2002 - Vinicius Vitoi Silva.pdf: 1054315 bytes, checksum: 51a5727d70f7700de341d0a3b25059da (MD5) Previous issue date: 2002-03-22 / This study was carried out under field conditions at the Agroecological Integrated Production System (AIPS) to chose the best option of cover crop to much the soil suface for broccoli organic managed in no-tillagem systems. The experiment was set in a randomized blocks design with four treatments during two years in the same field location. In the first year the treatment used was, sorghum; millet; sum hemp and weeds as control. In the second year was replaced to a misture sum hamp and sorghum to optimize the benefits of utilization of legume. The cover crop was cut and left in the soil surface as mulch to provide a thick residue that release nutrients and suppress growth of weeds and prove a best environment to broccoli development. This study included evaluation relating with biomas production, concentration and accumulation of nutrients at cover crop; decomposition rates and nutrients released at straws; weed community before and after cover crop was cut; broccoli marketable production and nutrients concentration at index leaves of broccoli. Sorghum; millet; sum hemp and sorghum plus sum hemp mixture production of straw was plus than 7,0 Mg ha-1 dry mass and proved a good much with the slowest decompositions rates. The decomposition rate and nutrient release rate was fast in weeds and slower in grass than legume. The mixture grass-legume has a intermediate rate whem is compared with sorghum and sun hemp monoculture. Legume accumulation plus Ca and grass plus K and P. The faster nutrient releases from mulch was K and the lowest was Ca, while N, P and Mg was variable among treatments. Legume grass mixture can improve quality of mulch because they have different root ability to nutrient up take. The straws of sorghum, millet, sum hemp and sorghum plus sum hemp mixture restring weed growth and show that is possible to reduce additional control measures. The index leaves of broccoli was able to show differences in nutrients up take only to K at the first year, when it was higher in broccoli planted in millet and sorghum residues, but at the second year N and P was higher in leaves of broccoli planted in sum hemp and mixture of sorghum plus sum hemp residue. At the broccoli marketable yield was better in cover crop than weeds. In the second year the mixture grass-legume effect in broccoli growth was similar to legume alone. / Foi conduzido um estudo de campo no Sistema Integrado de Produ??o Agroecol?gica (SIPA) com o objetivo de identificar a melhor op??o de planta de cobertura para produ??o de Br?colos (Brassica oleraceae L., var. italica) em Sistema Plantio Direto. Foi utilizado o delineamento experimental de blocos ao acaso com quatro repeti??es e quatro tratamentos e utilizado a mesma localiza??o no campo durante os dois anos. No primeiro experimento os tratamentos foram sorgo, milheto, crotal?ria e vegeta??o espont?nea como testemunha. No segundo experimento o tratamento com milheto foi substitu?do pelo cons?rcio entre sorgo e crotal?ria para otimizar o benef?cio da leguminosa. A cultura de cobertura foi cortada e deixada na superf?cie para forma a espessa camada de palha que libera nutriente, impede o crescimento de ervas e proporciona melhora ambiente para o crescimento do br?colo. O estudo incluiu a avalia??o da produ??o de fitomassa, teor e acumula??o de nutrientes nas plantas de cobertura; taxas de decomposi??o e libera??o de nutrientes da palhada; comunidade de plantas espont?neas antes e ap?s o corte das plantas de cobertura; produ??o comercial de br?colos e o teor de nutrientes na folha ?ndice do br?colos. Sorgo, milheto, crotal?ria e cons?rcio produziram acima de 7,0 Mg ha-1 de mat?ria seca proporcionando boa cobertura do solo cujas taxas de decomposi??o foram mais lentas. A decomposi??o e libera??o de nutrientes foi mais r?pida na vegeta??o espont?nea que nas gram?neas e leguminosa. O cons?rcio entre sorgo e crotal?ria apresentou taxa de decomposi??o intermedi?ria entre os valores observados nos tratamentos sorgo e crotal?ria solteiros, mas a libera??o de nutriente foi semelhante. A leguminosa acumulou maiores quantidades de N e Ca enquanto as gram?neas mais K e P. O nutriente K apresentou a maior velocidade de libera??o e Ca a menor velocidade de libera??o em todos tratamentos, enquanto N, P e Mg variaram entre tratamentos. O cons?rcio entre gram?nea e leguminosa melhora a qualidade da palhada devido a diferen?as na absor??o de nutrientes. A palhada de sorgo, milheto, crotal?ria e o cons?rcio crotal?ria e sorgo restringiram o estabelecimento de plantas espont?neas mostrando a viabilidade de reduzir a intensidade e freq??ncia de capinas. A folha ?ndice do br?colos identificou diferen?a na absor??o de nutrienntes apenas para o K no primeiro ano, quando foi maior no br?colos cultivado sobre res?duos de milheto e sorgo. No segundo ano o teor de N e P na folha ?ndice foi maior no br?colos cultivado sobre res?duos de crotal?ria e do cons?rcio. No primeiro ano todas as plantas de cobertura proporcionaram produ??o comercial de br?colos superior em rela??o ao controle com plantas espont?neas. No segundo ano o efeito dos res?duos de crotal?ria + sorgo proporcionou produ??o comercial semelhante ao melhor resultado que foi obtida sobre res?duos de crotal?ria solteira.