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Characterization of seed coat post harvest darkening and condensed tannin accumulation during seed coat development in common bean (<i>Phaseolus vulgaris</i>)Elsadr, Hanny Tarek 09 May 2011 (has links)
Seed coat biochemistry and colour are highly variable in common bean (Phaseolus vulgaris) (syn. dry bean). Genetic studies of dry bean seed coat chemistry and colour have important implications in breeding efforts for improving nutrition and seed quality for consumer acceptance. The results of this thesis detail the phenotypic and genotypic characterization of seed coat post harvest darkening (PHD) in parents and progeny of crosses among them as well as the phenotypic characterization of seed coat condensed tannin (CT) accumulation in five genotypes of bean.<p>
Seed coat PHD represents a problem for producers and consumers of several different market classes of dry bean. There are three post harvest darkening phenotypes: (i) non-darkening (ND), (ii) slow darkening (SD) and (iii) regular darkening (RD). The inheritance of PHD was determined by evaluating 28 populations derived from crosses between RD, SD and ND genotypes. Results suggest that at least two major, unlinked genes control the PHD trait in dry bean. Recessive epistasis with three phenotypic classes best explains the segregation ratios observed in populations from crosses between SD and ND parents. One gene, J, is responsible for whether a bean will darken and seeds of plants that are jj do not darken at all. Another gene, SD, influences the rate a seed coat will darken with seed from sdsd individuals darkening more slowly that those with the dominant SD allele.
Quantitative evaluation of seed coat PHD demonstrated that there was a wide range of darkening within any given PHD phenotype. Crosses made between the ND x ND cross class resulted in F2 progeny that were all ND, however, a wide range of seed coat background colours was noted in the progeny. In several of the crosses made between ND x RD and SD x RD classes the resulting F1 progeny were all RD; however, a wide range of RD phenotypes were observed in the F2 progeny. These phenotypes are not likely due to quantitative trait loci (QTL) associated with the PHD trait, but rather a result of other chemical reactions occurring in the seed coat. Condensed tannins (CT; syn. proanthocyanidins), kaempferols, polyphenol oxidase (PPO) and possibly other compounds or enzymes may be interacting and causing this quantitative range within any given genotype as a function of environmental variability, genotype and their interaction. CT have been associated with PHD but are not responsible for the major difference between RD and SD lines. They may, however be responsible for the quantitative nature of the phenotype.<p>
Condensed tannins can be harmful or beneficial to human health and the environment depending on the amount present and where it is found in the plant. Manipulating the production, accumulation and form of CT in the seed coat of dry bean would be beneficial to bean producers, consumers and breeders. This experiment quantitatively and qualitatively evaluated differences in patterns of CT accumulation in the seed coats of five genotypes of dry bean which exhibited low, medium or high concentrations of CT in their seed coats at maturity. Condensed tannin content was assessed from seeds harvested every other day from 6 40 days after flowering (DAF) using a modified BuOH-HCl assay. Results illustrated that CT accumulated as early in low CT genotypes as in high CT genotypes. CT content stabilized after 14 DAF in low CT genotypes. By contrast, CT content peaked then leveled off 30 DAF in moderate and high CT genotypes. A reduction in CT content in the higher CT lines was observed in the final stages of seed development.
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Grapefruit-drug interaction: isolation, synthesis, and biological activities of furocoumarins and their variation due to pre- and post-harvest factors.Girennavar, Basavaraj 15 May 2009 (has links)
The health maintaining properties of citrus consumption are attributed to the wide
assortment of bioactive compounds. Consumption of grapefruit along with certain
medications, however, is posing a risk of drug toxicity and side reactions. The first study
involved isolation of bioactive furocoumarins with a combination of chromatographic
techniques and synthesis. Five furocoumarins namely, dihydroxybergamottin, paradisin
A, bergamottin, bergaptol and geranylcoumarin were isolated from grapefruit and series
of furocoumarin monomers and paradisin A were synthesized. The second study involved
influence of pre- and post-harvest factors on the levels of furocoumarins in grapefruit
juice. Considerable differences were observed in the levels of these compounds in
different grapefruit cultivars. Ray Red showed the lowest levels of all three
furocoumarins and Duncan contains the highest amount of DHB and bergamottin, where
as the highest levels of paradisin A was observed in Star Ruby. The highest levels of
DHB and bergamottin were found in Flame cultivar grown in California. The changes in
the levels of these furocoumarins during the season in Rio Red and Marsh White
grapefruit cultivars were evaluated. The third study investigated biological activities of grapefruit juices and
furocoumarins. Grapefruit and Pummelo juices were found to be potent inhibitors of
cytochrome CYP3A4 and CYP2C9 isoenzymes at 5% concentration while CYP2D6 was
less affected. Among the five furocoumarins tested, the inhibitory potency was in the
order of paradisin A>dihydroxybergamottin>bergamottin>bergaptol>geranylcoumarin at
0.1 µM to 0.1 mM concentrations. A fourth study investigated the effect of
furocoumarins on bacterial auto-inducer signaling, and found that furocoumarins are
potent inhibitors of AI-1 and AI-2 activities at 0.01% concentration. In a fifth study,
involving synthesized furocoumarin monomers and dimer on anti-proliferative activities
on normal and cancer cell lines, furocoumarins found to be non-toxic to normal cells.
However, bergamottin showed a significant anti-proliferative activity in HT-29 and
MCF-7 cell lines.
This dissertation indicates that furocoumarins are bioactive compounds from
grapefruit juice with potent inhibitory property of major drug metabolizing cytochrome
P450 isoenzymes. Furocoumarins show a considerable variation between varieties,
location and season. These results corroborate the involvement of furocoumarins in
grapefruit drug interaction.
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Mortality in the Yukon: Post-harvest Effects on Structural RetentionSmith, Fraser 15 February 2010 (has links)
Structural retention harvesting represents one of the most important recent silvicultural innovations and is widely practiced in the harvesting of mature boreal stands. Following structural retention harvests, mortality of retained trees is often dramatically elevated compared to pre-harvest stands. I examined tree mortality following structural retention harvests in the southeastern Yukon Territory, using dendrochronological techniques to quantify annual mortality. I estimated integrated losses in the first five years to be at least 17.3% of retained stems. Analysis of mortality type showed that windthrow was the most important post-harvest mortality mechanism. This study represents the first analysis of mortality responses following structural retention harvests in the northern extent of operational forestry in Canada. Rates of post-harvest tree mortality observed in this study are among the highest reported to date from managed Canadian boreal forests, indicating that greater attention must be given to post-harvest stand responses if sustainable forestry practices are desired.
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Mortality in the Yukon: Post-harvest Effects on Structural RetentionSmith, Fraser 15 February 2010 (has links)
Structural retention harvesting represents one of the most important recent silvicultural innovations and is widely practiced in the harvesting of mature boreal stands. Following structural retention harvests, mortality of retained trees is often dramatically elevated compared to pre-harvest stands. I examined tree mortality following structural retention harvests in the southeastern Yukon Territory, using dendrochronological techniques to quantify annual mortality. I estimated integrated losses in the first five years to be at least 17.3% of retained stems. Analysis of mortality type showed that windthrow was the most important post-harvest mortality mechanism. This study represents the first analysis of mortality responses following structural retention harvests in the northern extent of operational forestry in Canada. Rates of post-harvest tree mortality observed in this study are among the highest reported to date from managed Canadian boreal forests, indicating that greater attention must be given to post-harvest stand responses if sustainable forestry practices are desired.
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Synergistic effects of mixtures of fungicides and medicinal plant extracts against Botrytis cinereaVries, Filicity Ann January 2008 (has links)
<p>We hypothesize that South African medicinal plants contain compounds that can act in synergism with synthetic antifungal compounds. Four fungicides - Sporekill&trade / , Rovral&trade / , Terminator&trade / and Teldor&trade / at doses 0.1, 0.2, 0.4 and 0.8 mL L-1 and plant species Galenia africana, Elytropappus rhinocerotis and Tulbaghia violacea were tested aloneand in different combinations for their potency (efficacy) on radial growth inhibition of Botrytis cinerea strains on potato dextrose plates. Four doses of plant extract for each of the respective plant species were used. A total of 48 combinations were tested for each strain. Mixtures of plant extracts were far more effective in controlling strains compared to the individual components alone, representing significant levels of in vitro synergistic interactions. Combinations of these components represent an attractive future prospect for the development of new management strategies for controlling B. cinerea. Since the in vitro tests of these mixtures showed inhibitory activity, the mixtures were tested for activity in assays on Granny Smith apples. In vitro tests can be used to screen mixtures to obtain information on their inhibitory activity on a pathogen, however, the environmental conditions of the fruit and the ability of the pathogen to grow into the fruit cannot be simulated in vivo. A series of two-fold doses of medicinal plant extracts were combined with fungicides to conduct decay inhibition studies. The incidence of gray mold was significantly reduced by mixtures of plant extracts and fungicides. Under conditions similar to those in commercial storage, a drench treatment with G. africana and Rovral&trade / significantly (p=0.05) inhibit gray mold on the apples and was more effective than the plant extract and fungicide alone. The treatments exerted synergistic effects and were markedly better than the components applied alone. The wound colonization assay was used for optimal decay control. In a drench, much higher volumes of the treatments are used to ensure that the components of the suspension are deposited evenly over the entire fruit surface. Drenching of fruit to apply other chemicals is an established practise in the pome (fleshy) fruit industry, and simplifies the commercial application of the mixtures, as no additional infrastructure at commercial packing houses will be required. This approach not only makes it possible to reduce fungicide concentrations while maintaining adequate decay control, but also ensures a reduction of the chemical residue on the fruit.</p>
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Pressure regulated silicone membrane gas permeator for long term CA storage of fruits and vegetablesGariépy, Yvan January 1988 (has links)
No description available.
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Synergistic effects of mixtures of fungicides and medicinal plant extracts against Botrytis cinereaVries, Filicity Ann January 2008 (has links)
<p>We hypothesize that South African medicinal plants contain compounds that can act in synergism with synthetic antifungal compounds. Four fungicides - Sporekill&trade / , Rovral&trade / , Terminator&trade / and Teldor&trade / at doses 0.1, 0.2, 0.4 and 0.8 mL L-1 and plant species Galenia africana, Elytropappus rhinocerotis and Tulbaghia violacea were tested aloneand in different combinations for their potency (efficacy) on radial growth inhibition of Botrytis cinerea strains on potato dextrose plates. Four doses of plant extract for each of the respective plant species were used. A total of 48 combinations were tested for each strain. Mixtures of plant extracts were far more effective in controlling strains compared to the individual components alone, representing significant levels of in vitro synergistic interactions. Combinations of these components represent an attractive future prospect for the development of new management strategies for controlling B. cinerea. Since the in vitro tests of these mixtures showed inhibitory activity, the mixtures were tested for activity in assays on Granny Smith apples. In vitro tests can be used to screen mixtures to obtain information on their inhibitory activity on a pathogen, however, the environmental conditions of the fruit and the ability of the pathogen to grow into the fruit cannot be simulated in vivo. A series of two-fold doses of medicinal plant extracts were combined with fungicides to conduct decay inhibition studies. The incidence of gray mold was significantly reduced by mixtures of plant extracts and fungicides. Under conditions similar to those in commercial storage, a drench treatment with G. africana and Rovral&trade / significantly (p=0.05) inhibit gray mold on the apples and was more effective than the plant extract and fungicide alone. The treatments exerted synergistic effects and were markedly better than the components applied alone. The wound colonization assay was used for optimal decay control. In a drench, much higher volumes of the treatments are used to ensure that the components of the suspension are deposited evenly over the entire fruit surface. Drenching of fruit to apply other chemicals is an established practise in the pome (fleshy) fruit industry, and simplifies the commercial application of the mixtures, as no additional infrastructure at commercial packing houses will be required. This approach not only makes it possible to reduce fungicide concentrations while maintaining adequate decay control, but also ensures a reduction of the chemical residue on the fruit.</p>
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Sweet corn seed quality in relation to seed production and postharvest handlingParwata, I. G. Unknown Date (has links)
No description available.
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Studies on continuous sugar centrifugesGreig, Christopher R. (Christopher Roy) Unknown Date (has links)
No description available.
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Advancing harvest maturity and improving storability of ‘Triumph' persimmonsBill, Malick 03 1900 (has links)
Thesis (MScAgric)--Stellenbosch University, 2012. / ENGLISH ABSTRACT: ‘Triumph’ persimmon production in South Africa is export driven and the profitability
of the industry is largely dependent on consumer demand and supermarket shelf
space in the European market. In order to realise high returns, it is important to
advance harvest maturity to attain early fruit that arrives on the market prior to
European summer fruits. In addition, market feedback suggests that fruit picked
during the second half of the harvesting period stores poorly and rapidly softens
during shelf life. It is important to establish whether this is the case.
The effect of paclobutrazol (PBZ) application rate on fruit maturity and keeping
quality, return bloom and vegetative growth was investigated over two seasons.
Advanced harvest maturity was attained at a compromise of reduced fruit storage
quality and stunted growth with the severity of the compromise increasing with
increasing PBZ application rate. To advance harvest maturity while maintaining
acceptable keeping quality, PBZ application at 0.75 ml per plant is recommended
although effects on harvest maturity will not persist into the subsequent season as
found at higher application rates.
Prohexadione-calcium (P-Ca) as an alternative for PBZ in advancing harvest
maturity was evaluated over two seasons. A positive response to three foliar
applications of P-Ca at 200 mg·L-1 was noticed in the first season. In the second
season, a single application of P-Ca at 300 mg·L-1 two weeks before harvest
significantly advanced harvest maturity. Due to the rapid metabolism of P-Ca in the
plant, it is unlikely that growth in the subsequent season will be affected. Based on
these results, the persimmon industry will undertake commercial trials in the 2012
season to further assess the efficacy of P-Ca application in advancing harvest
maturity.
The effect of various rest breaking agents (RBAs) on bud break, flowering, fruit
maturity and quality as well as vegetative growth was assessed for one season.
RBAs did not increase or advance bud break and flowering. Consequently, yield and harvest maturity were unaffected by the treatments. The ineffectiveness of the RBAs
could be due to the low application rates used or the fulfilment of the chilling
requirement prior to treatment application.
An experiment was carried out to determine whether storability and shelf-life differ
between “early” and “late” production areas in South Africa as well as between
orchards within these areas. The data indicated that fruit colour is a good maturity
parameter and indicator of fruit storability. However, “late” fruit were about 1 kg softer
than “early” fruit at the same colour chart value. We therefore recommend that fruit
from late regions are harvested at colour chart values of 5 and 6 (yellow-green)
instead of 3 and 4. Fruit from “late” orchards as well as GA3-treated fruit with a colour
chart value of 3 and less should be culled due to the high propensity (>20%) of these
fruit to become soft during storage and shelf life. A delay in 1-MCP treatment and
interruption of the cold chain considerably increased fruit softening during storage
and shelf-life. Further research is required to verify this result. / AFRIKAANSE OPSOMMING: ‘Triumph’ persimmon produksie in Suid-Afrika is uitvoergedrewe en die
winsgewendheid van die bedryf is grootliks afhanklik van verbruikervraag en
supermark spasie in die Europese mark. Ten einde hoë pryse te realiseer, is dit
belangrik om ʼn vroeë oes te verkry sodat vrugte voor die Europese somervrugte op
die mark beland. Mark terugvoer dui verder daarop dat vrugte wat tydens die tweede
helfte van die oesperiode gepluk word, swakker opberg en vinnig sag word
gedurende op die rak. Dit is belangrik om vas te stel of hierdie waarneming juis is.
Die effek van paklobutrazol (PBZ) toedieningshoeveelheid op vrugrypwording en -
houvermoë, opvolgblom en vegetatiewe groei is oor twee seisoene ondersoek.
Oesrypheid is vervroeg, maar tot nadeel van vrughouvermoë en vegetatiewe groei.
Die omvang van die negatiewe effekte van PBZ het toegeneem met ʼn toename in
toedieningshoeveelheid. Ten einde oesrypheid te vervroeg terwyl aanvaarbare
houvermoë behou word, word toediening van PBZ teen 0.75 ml per plant aanbeveel
alhoewel die effek op oesrypheid anders as die geval met hoër
toedieningshoeveelhede nie in die opeenvolgende seisoen sal voortduur nie.
Proheksadioon-kalsium (P-Ca) as alternatief tot PBZ om oesrypheid te vervroeg is
oor twee seisoene gee-valueer. ʼn Positiewe effek op vrugrypwording is in die eerste
seisoen verkry met drie blaartoedienings van P-Ca teen 200 mg·L-1. In die tweede
seisoen is oesrypheid betekenisvol vervroeg deur ʼn enkel toediening van 300 mg·L-1
P-Ca ʼn maand voor oes. Vanweë hierdie resultate gaan die persimmonbedryf in die
2012 seisoen kommersiële proewe onderneem om die effektiwiteit van P-Ca om oes
te vervroeg, verder te ondersoek.
Die effek van verskeie rusbrekende middels (RBAs) op bot, blom, vrugrypheid,
vrugkwaliteit en vegetatiewe groei is vir een seisoen ondersoek. RBAs het bot en
blom vervroeg of vermeerder nie en het daarom ook geen effek op produksie en
oesrypheid gehad nie. Die oneffektiwiteit van die RBAs kan moontlik toegeskryf word aan die lae toedieningsvlakke wat gebruik is of aan die kouebehoefte wat bevredig is
voor toediening van RBAs.
ʼn Eksperiment is gedoen om vas te stel of die opberging- en houvermoë van vrugte
verskil tussen “vroeë” en “laat” produksieareas in Suid-Afrika en ook tussen boorde
in hierdie areas. Die data dui daarop dat vrugkleur ʼn goeie rypheidsparameter en
indikator van opbergingsvermoë is. Vrugte van laat areas was egter omtrent 1 kg
sagter as vrugte van vroeë areas van dieselfde kleur. Ons beveel gevolglik aan dat
vrugte van laat areas by ʼn kleurkaartwaarde van 5 tot 6 (geelgroen) geoes word
eerder as by 3 tot 4. Vrugte van laat boorde sowel as vrugte wat met GA3 behandel
is met ʼn kleurkaartwaarde van 3 en laer moet afgradeer word weens die hoë
geneigdheid (>20%) van hierdie vrugte om sag te word tydens opberging en op die
rak. Uitstel van 1-MCP behandeling en die onderbreking van die koueketting
veroorsaak ʼn aansienlike toename in sagte vrugte tydens opberging en op die rak.
Verdere navorsing word benodig om hierdie resultaat te verifieer.
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