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Shrubs for Northern Arizona above 6000 Foot ElevationsDeGomez, Tom 01 1900 (has links)
7 pp. / Shrubs can greatly enhance the landscaping of your home year round. Different types of shrubs, their landscape usage, selection and cultural requirements are discussed here in detail.
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The Performance of Gazania Splendens Cultivars Under Kentucky ConditionsJustiss, Ellen Sue 01 January 1985 (has links)
Gazania splendens is a tender, herbaceous perennial that belongs to the Compositae family. The leaves are green and glabrous above, white tomentose beneath, toothed, simple and/or pinnatifid, 4”-6” long tapering to a winged petiole, lanceolate to obovate-lanceolate, and arranged in a basal clump. The flower heads are large, showy, 2”-3” in diameter, and range in color from white to yellow, orange, pink, purple, ruby, and bronze with a dark ring or spot at the base of most.
Twelve cultivars of Gazania splendens were to be evaluated to determine which would perform the best under Kentucky conditions. A seed germination test was conducted to check the environmental conditions thought to give the best germination rate. Physical characteristics were observed for each cultivar throughout the growing season.
A seed germination test was conducted using seed from ‘Sundance Red’ and ‘Sundance Striped.’ The seeds were tested at both 15.5°C and 22°C in light and dark conditions. The highest percentage of seeds germinated at 22°C in the dark.
Seed from each cultivar was sown in flats containing Jiffy Mix Plus media, watered, covered with black plastic and white Styrofoam trays, and put in the greenhouse for germination. The seedlings were transplanted into cell packs containing Sunshine Mix media. ‘Sundance Red’ had a very low germination percentage and was the only cultivar not transplanted. The plants were later planted in beds at the Western Kentucky University Farm.
Physical characteristics were evaluated throughout the growing season. In the evaluation, monthly flower counts were taken, flower stem stiffness was measured, plant height was measured, plant width was measured, foliage characteristics were noted, and spent flower heads and dead leaves were observed. The flowers were also observed throughout the growing season to evaluate their opening and closing habits. This characteristic is thought to be in response to the amount of sunlight the plant receives.
From the evaluation, it was found that ‘Grandiflora Mixture,’ ‘Golden Margarita,’ ‘Ministar Yellow,’ ‘Sundance Yellow,’ and ‘Ministar Mixture’ were the best cultivars for Kentucky. These cultivars exhibited abundant flowers, strong flower stems, good foliage characteristics, and spent flower heads and dead leaves went unnoticed throughout the growing season.
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JARDINS DE TERRE, JARDINS DE MER À TONGOA (VANUATU) Une anthropologie de la nature domestique dans un milieu affecté par la catastrophe / GARDENS OF EARTH, SEA GARDENS IN TONGOA (VANUATU) An anthropology of the domestic nature in an environment affected by the disasterCalandra, Maëlle 11 December 2017 (has links)
Fondée sur dix-sept mois d’enquête ethnographique à Tongoa (entre 2013 et 2015), une île du Vanuatu, cette thèse et la réflexion qui la sous-tend portent sur les espaces travaillés, en mer comme sur terre. Elle prend comme fil conducteur les jardins de subsistance et met en évidence les relations qu’entretiennent les habitants de l’île, tant entre eux et avec ces deux types d’espaces, qu’avec les collectifs de non-humains qui peuplent leur monde. L’étude de la nature domestique révèle que la terre et la mer sont pensées dans un cadre commun et montre en quoi elles sont constitutives du mode de vie et des représentations de ceux qui les créent et les exploitent. L’environnement dans lequel évoluent les Man-Tongoa est marqué du sceau de catastrophes, dont la contingence constitue, pour eux, un inéluctable donné de l’existence. Les espaces appropriés sont régulièrement bouleversés, voire temporairement anéantis, par un événement sismique ou climatique de grande ampleur – comme le cyclone Pam, intervenu en mars 2015. L’ethnographie de cet événement et l’étude des différents phénomènes relevant de la catégorie locale de disasta démontrent comment est localement construite la notion de catastrophe lorsque la « tradition », les dénominations chrétiennes et les ONG en proposent des explications parfois incompatibles. / Based on seventeen months of fieldwork carried out between 2013 and 2015 on Tongoa, an island in the archipelago of Vanuatu, the present PhD dissertation and its underlying reflection aim to study domesticated spaces, both on the ground and in the sea. This research explores and follows the logics of subsistence gardens, underlying the relationships cultivated both between islanders and these spaces, and between them and the non-human entities inhabiting their world. Such an approach helps underline how the land and the sea are conceptualised in a common frame of understanding, and shows how both spaces equally build up the way of living and thinking of those who create them and tap into their resources. The environment of the Man-Tongoa bears the weight of potential disasters, whose very contingency is an inescapable given of daily reality. The appropriated spaces are regularly shattered, sometimes even temporarily wrecked, by large-scale seismic or climatic events – as demonstrated by the cyclone Pam, which took place in March 2015. The ethnography of this event and the analysis of the various phenomena pertaining to the local category of disasta demonstrate how the notion of disaster is locally constructed, when “tradition”, Christian denominations, and NGOs offer non mutually intelligible or compatible explanations.
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The Western Kentucky University Teaching Gardens: Landscape Design and Establishment PlanStetter, Claudia 01 May 2011 (has links)
The purpose of this thesis is to design a landscape plan for Teaching Gardens at the Western Kentucky University Agriculture Research and Education Center. The landscape plans were selected based upon the available 5.3 acres surrounding the greenhouse, vineyard, and Exposition Center. Planning included goals and objectives, analysis of the available site, landscape design plans, and connecting the Teaching Gardens to the current curriculum. This thesis also includes related areas to the development of Teaching Gardens such as: summary of courses with related topics to Teaching Gardens, programs that will be used throughout the community, and a listing of current and estimated future costs/expenses plus funding avenues to support this endeavor. The implementation of the Gardens in this thesis has created an area of learning for the Agriculture Department, university, and local community. The Teaching Gardens are an extension of the classroom learning experience, which provide research opportunities, harvest/care information, and promote healthy nutrition. The Teaching Gardens provide a naturally beautiful atmosphere for the enjoyment of students, faculty and staff, and the local community.
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Shrubs for Northern Arizona Above 6,000 Foot ElevationsBraun, Hattie, DeGomez, Tom 03 1900 (has links)
Revised; Originally Published: 2003 / 7 pp.
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An investigation of four television teaching feedback techniques via a closed-circuit systemCopeland, J. B. January 1966 (has links)
Thesis (Ph. D.)--University of Wisconsin, 1966. / Extension Repository Collection. Typescript (photocopy). eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.
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Factors affecting shrivelling and friction discolouration of pears (Pyrus communis L. )Burger, G. E. (Gerrit Erasmus) 04 1900 (has links)
Thesis (MScAgric)--University of Stellenbosch, 2005. / ENGLISH ABSTRACT: Shrivelling and friction discolouration (FD), as postharvest disorders, negatively influence
the marketability and potential shelf life of pears. By investigating the contributing factors in
each of the disorders, the potential involvement of handling and storage variables were
determined. This allowed for a better understanding of the responsible factors that create
susceptible environments for these disorders to occur.
From the moment that pears are harvested they lose weight by means of transpiration and, to
a lesser extent, respiration. When excessive losses are experienced, the fruit will appear
shrivelled and the marketability and shelf life are negatively influenced. By minimizing the
rates of weight loss, the occurrence of shrivelling among pears during the postharvest
handling can be lessened. The periods that proved to be most conducive to shrivelling (during
a simulated postharvest handling duration) were where temperatures above 0 °C were
experienced. These short periods proved more perilous for shrivelling than lengthy storage
durations at low temperatures. This influenced the transpiration rate in such a way that the
driving force accelerated the rate of weight loss in all the cultivars that were studied.
Removing field heat from fresh produce and maintaining the cold chain reduces the driving
force behind the transpiration of the pears.
In all the cultivars studied, ‘Packham’s Triumph’, ‘Beurrè Bosc’ and ‘Forelle’, smaller and
less mature fruit were more inclined to appear shrivelled. The surface area to volume ratio is
fundamental in determining the rate of weight loss. This was most evident in ‘Beurrè Bosc’.
Although no reproducible results could be obtained from the morphological studies, literature
has attributed this phenomenon to the composition and quantity of the cuticle layer.
Reduction of weight loss was obtained by sealing of the fruit stem. This obstructed water
movement from the fruit through the xylem conducting tissue to the surrounding atmosphere.
Not only did the stem appear greener and fresher, but less weight loss and subsequent shrivel
was noticeable in the treated fruit. This effect was most evident in ‘Packham’s Triumph’ and
‘Beurrè Bosc’, but not in ‘Forelle’. ‘Forelle’ typically has a very short, thin stem in
comparison to the other two cultivars.All the cultivars showed visual shrivel symptoms after 11 days at 18 °C. Rate of weight loss
was the lowest in ‘Packham’s Triumph’, but due to its prominent dimensions, it appeared
shrivelled before any of the other cultivars. ‘Beurrè Bosc’ lost weight at the highest rate
(0.42%.day-1).
As fruit injury, in the presence of oxygen, is inevitable, the oxidative enzymatic browning of
pears will always be troublesome. This defensive mechanism partially prevents the infection
of the fruit where epidermal cells are injured. To minimize FD, impact and frictional forces
need to be lower during both harvesting and handling practices.
A laboratory scale method was developed through which reproduceable treatments could be
performed, thereby subjecting the fruit to industry related friction, rather than impact, injury.
By assessing the discolouration in terms of both extent and intensity, the influence of
variables could be determined on both ‘Packham’s Triumph’ and ‘Doyenne du Comice’
pears. As also found in practice, ‘Doyenne du Comice’ proved to be far more susceptible to
FD than ‘Packham’s Triumph’, although the activity of the enzyme, polyphenol oxidase
(PPO) was found to be higher in the latter.
Although no significant difference was found between the FD encountered at fruit
temperature of 3 °C and 15 °C, discolouration was greater at the higher temperature. This
might be attributed to a greater degree of water loss, lower cell turgidity or higher enzyme
activity. Thus, fruit taken from storage and sorted directly thereafter will exhibit less FD. The
contribution of condensation forming on the fruit, acting as lubrication, cannot be ignored.
Such fruit, with high turgor pressure, might again be more susceptible to bruising which will
only be revealed well after the injury. Since enzymes, which include PPO, catalyse
biochemical reactions, the availability of sufficient substrate most probably regulates the
extent of this biochemical discolouration.
Harvesting at optimum maturity and preventing any unnecessary friction will most definitely
reduce the occurrence of FD. The ultimate challenge remains to optimize sorting and packing
conditions without compromising on fruit quality. / AFRIKAANSE OPSOMMING: Verrimpeling en friksie verbruining (FV), as na-oes defekte, het ’n negatiewe invloed op die
bemarkbaarheid en potensiële raklewe van pere. Hierdie studie het die bydraende faktore vir
elkeen van die defekte ondersoek. Daar is gepoog om die effek van verskillende hanteringsen
opbergingsmetodes op bogenoemde defekte te bepaal. ‘n Beter begrip is verkry van die
oorsaaklike faktore wat bydra tot die ontstaan van die betrokke defekte.
Direk na die oes van pere, begin die vrug gewig verloor as gevolg van veral transpirasie.
Oormatige verliese sal lei tot ’n vrug wat verrimpeld voorkom, met ‘n negatiewe invloed op
die bemarkbaarheid en raklewe daarvan. Die voorkoms van die verrimpeling van pere tydens
die na-oes hantering van die vrugte, kan verminder word deur vermindering van die tempo
van gewigsverlies. Die periodes waartydens die verrimpeling veral voorgekom het, (soos
gevind in ’n gesimuleerde na-oes hanteringsmodel) was wanneer temperature bo 0 °C
ondervind is. Sulke kort periodes was meer geneig om aanleiding te gee tot verrimpeling as
die verlengde periodes van opberging by lae temperature. Sulke periodes van hoër
temperature het gelei tot versnelde transpirasie en ’n versnelde tempo van gewigsverlies in al
die kultivars wat ondersoek is. Die transpirasietempo van pere kan verlaag word deur die
verwydering van veld-hitte en deur die streng behoud van die koue-ketting.
In al die kultivars wat ondersoek is, ‘Packham’s Triumph’, ‘Beurrè Bosc’ en ‘Forelle’, is
gevind dat die kleiner en minder volwasse vrugte meer geneig was tot verrimpeling. Die
oppervlak area tot volume verhouding is krities in die bepaling van die tempo van
gewigsverlies. Hierdie bevinding was die prominentste in ‘Beurrè Bosc’. Alhoewel geen
beduidende resultate verkry kon word van die morfologiese studies nie, is daar verskeie
verwysings in die literatuur wat hierdie verskynsel toeskryf aan die samestelling en
hoeveelheid van die kutikula laag.
Vermindering van gewigsverlies is verkry deur verseëling van die vrugtestingel. Hierdie
tegniek het gelei tot ’n blokkering van die watervloei van die vrug na die omgewing deur die
xileem weefsel. Verseëling van die stingel het dit groener en varser laat voorkom, en het ook
’n merkbare vermindering in gewigsverlies en die daaropvolgende verrimpeling tot gevolg
gehad. Die effek van stingel-verseëling was die prominentste in ‘Packham’s Triumph’ en‘Beurrè Bosc’. Dit was minder duidelik in ‘Forelle’ wat tipies gekenmerk word deur ‘n baie
korter, dun stingel in vergelyking met die ander twee kultivars.
Al die kultivars het makroskopiese verrimpeling getoon na ‘n opbergingperiode van 11 dae
by 18 °C. Die tempo van gewigsverlies was die laagste in ‘Packham’s Triumph’ alhoewel dit
eerste verrimpeld voorgekom het. Dit kan toegeskryf word aan die spesifieke afmetings van
hierdie betrokke kultivar. ‘Beurrè Bosc’ het vinnigste gewig verloor (0.42%.dag-1).
Aangesien die besering van vrugte, in die aanwesigheid van suurstof, onvermydelik is, sal
oksidatiewe, ensiematiese verbruining van pere altyd problematies wees. Hierdie
verdedigingsmeganisme voorkom tot ’n mate die infeksie van die vrug wanneer epidermale
selle beskadig word. FV kan beperk word deur die vrugte tydens oes en hanteringsprosedures
so min as moontlik bloot te stel aan impak en friksie kragte.
’n Laboratorium-model is ontwikkel ter nabootsing van die omstandighede in die industrie.
Die vrugte is aan friksie, eerder as impak, onderwerp, soos ondervind in die industrie. Die
omvang asook die intensiteit van die verbruining is gemeet in beide ‘Packham’s Triumph’ en
‘Doyenne du Comice’ pere. Op hierdie wyse kon die invloed van die onderskeie
veranderlikes in elke kultivar bepaal word. Alhoewel die ensiematiese aktiwiteit van die
polifenol oksidase ensiem (PFO) die hoogste in ‘Packham’s Triumph’ was, is gevind dat
‘Doyenne du Comice’ veel meer geneig was tot FV as ‘Packham’s Triumph’. Hierdie
bevinding bevestig die verskynsel soos in die praktyk gevind.
Alhoewel geen betekenisvolle verskil gevind is tussen FV by vrug temperatuur van 3 °C en
15 °C nie, was daar meer verbruining by die hoër temperatuur. Hierdie verskynsel kan
toegeskryf word aan ’n groter mate van waterverlies, laer sel turgiditeit en hoër ensiem
aktiwiteit. Dus sal vrugte wat direk na opberging gesorteer word, minder FV toon. Die bydrae
van die kondensasie wat op die vrug vorm, en as ’n smeermiddel dien, kan nie geïgnoreer
word nie. Sulke vrugte met hoër turgiditeit, mag egter meer vatbaar wees vir kneusing, wat
egter eers ’n geruime tyd na die kneusing tevoorverskyn mag kom. Aangesien ensieme, wat
PFO insluit, as katalis dien in biochemiese reaksies, sal die beskikbaarheid van voldoende
substraat, na alle waarskynlikheid die omvang van die biochemiese verkleuring reguleer.Die oes van pere tydens optimum volwassenheid, en die voorkoming van onnodige friksie sal
definitief die voorkoms van FV verminder. Die uitdaging is steeds om sortering- en
verpakkingstegnieke verder te verfyn sonder om ’n negatiewe invloed op vrugtekwaliteit te
hê.
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Comparative financial efficiency of training systems and rootstocks for 'Alpine' nectarines (Prunus persica var. nectarine)Maree, Waldo J. 03 1900 (has links)
Thesis (MScAgric (Horticulture))--University of Stellenbosch, 2007. / Most nectarine orchards in South Africa are currently planted at a distance of 4 x
1.5 m (2 500 trees/ha). These trees are mainly sylleptically trained to a central leader,
although many producers also use the proleptic route. The former produces relatively
high yields early in the lifetime of the orchard. A problem with nectarine production in
South Africa is the lack of efficient rootstocks in terms of aspects such as size-control
and the use of nematode-resistant rootstocks. The aim of this study is to evaluate different
training systems for nectarine production and to investigate the role of three rootstocks
that play a dominant role in the peach industry in South Africa.
‘Alpine’ nectarines were planted in the winter of 2002 at Lushof near Ceres, Western
Cape, South Africa (33º18’S, 19º20’E). The trees were trained according to four different
training systems: a four-leader system (5 x 3 m; 667 trees/ha), a two-leader system (5 x
1.5 m; 1 333 trees/ha), a proleptically trained central leader (5 x 1 m; 2 000 trees/ha), and
a sylleptically trained central leader (5 x 1 m; 2 000 trees/ha). The trees were planted on
three different rootstocks: GF 667; SAPO 778; Kakamas seedling. The time spent per tree
on pruning, thinning and picking was recorded. During harvest, the number of fruit and
fruit mass per tree were recorded. Light measurements were recorded annually after
summer pruning. The measurements were taken at different heights and at different
depths in the canopy. To compare the training systems on an economic basis, the data
from the trial together with projected data gathered from farmers and advisors were used
to calculate the net present value (NPV) and internal rate of return (IRR) for each training
system.
The results showed that rootstock only played a significant role when it came to fruit
mass (fruit size). Fruit from trees on SAPO 778 were heavier, indicating bigger fruit, than
fruit from trees on Kakamas seedling rootstocks and this can play a role in packout
percentage and income. In terms of the training system, the four-leader system took the
most time to manage per tree. However, this system took the least time to manage per
hectare during the initial years. No differences were found between the two central leaders. They both took the longest
time to manage per hectare. The four-leader system produced significantly less fruit than
any of the other systems during the first two years of production. In the third year of
production, there was no significant difference found between the systems.
Light penetration seemed to be the poorest at the middle and bottom of the canopy for
trees trained to a central leader. Because of the open centre of the four-leader system,
light penetration into the middle of these trees was good, but poor light penetration
occurred in the upper and outer parts of the canopy underneath the scaffold branches.
Poor light penetration occurred in the parts lower than 1.5 m from the ground for all the
systems. This was the area that was measured in this study.
The result of an economic comparison showed that according to the IRR rating, the fourleader
system should be preferred. The final decision should however be made according
to the NPV rating. Results obtained from NPV calculations did not lead to the same
conclusions as could be made from the IRR calculations. According to the rating of the
NPV at five percent discounting rate, the two-leader should be the preferred system,
while the proleptically trained central leader system should be preferred at a ten percent
discounting rate. This implies that when the opportunity cost is low, the two-leader
system should be preferred, and when the opportunity cost is high, the proleptically
trained central leader system should be preferred.
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Evaluating the seasonal changes in calcium concentration and distribution in apple fruit after application of different calcium fertilisation strategiesWilsdorf, Robert Ernst 12 1900 (has links)
Thesis (MScAgric)--Stellenbosch University, 2011. / ENGLISH ABSTRACT: Localized calcium (Ca) deficiencies frequently develop independent from total Ca supply and total fruit Ca concentration. Bulk mineral analyses is therefore not completely suitable for determination of the susceptibility of fruit in developing Ca-linked fruit physiological disorders like bitter pit, as it supplies insufficient information regarding the spatial accumulation of Ca within the fruit. Additional Ca is applied either as soil or foliar applications, where soil applications are applied either after fruit set (pre-harvest) or in the period after harvest. The contribution of these different methods of Ca application to the total Ca concentration in "Braeburn" fruit was quantified over three consecutive growing seasons. Foliar applications have been proven to be successful in suppressing bitter pit development and improving the Ca status of the fruit. The effectiveness of different formulations of foliar Ca products in influencing these parameters was also determined. Furthermore, the distribution pattern of fruit Ca resulting from different application strategies was mapped using particle induced X-ray emission technology.
In the "Braeburn" trial, mineral analyses indicated no significant differences between treatments in terms of Ca concentration at 80 days after full bloom (dafb). However, when soil applications occurred with active root growth (visually monitored), treatments differed significantly 80 dafb. Weekly foliar Ca applications from 28 dafb resulted in higher fruit Ca concentrations 80 dafb than a pre-harvest soil Ca application (January, 2010). A possible explanation for the inefficiency of pre-harvest soil Ca is the disintegration of xylem vessels from 40 dafb (before root uptake) for sensitive cultivars such as Braeburn. Bitter pit initiation has been shown to occur in the earlier part of the season. This, together with a reduced Ca supply to the fruit early in the season due to xylem disintegration (for sensitive cultivars), indicates the importance of early season foliar Ca applications. PIXE analyses were used to establish the radial Ca distribution in apples. Ca was concentrated in the skin and core, with very low values in the outer cortex. PIXE results indicated fruit Ca concentrations to be the lowest in the pre-harvest soil application treatment. This was in agreement with mineral analyses results. Ca enriched areas resulting from effective Ca delivery via the vascular bundles, had a profound effect on fruit Ca concentrations in the immediate core and cortex. At harvest, this effect was much more subtle and emphasizes the importance of untimely xylem rupturing on eventual fruit Ca concentration. At 80 dafb, treatments where foliar Ca was applied showed higher Ca concentrations in the outer cortex (where symptoms of bitter pit typically occur).
Calflo™ fruit had significantly higher Ca concentrations in "Braeburn" compared to fruits from Foliar GS™ and GG™ treatments. Calflo™ and Calcimax™ had a higher active Ca percentage (12%) compared to Foliar GSTM and GGTM (10%). Adding the Lecithin™ (surfactant) to Calcimax™ is not recommended as it did not improve its uptake.
In "Golden Delicious", the commercial spray program of seven, weekly foliar applications (Calcinit™) resulted in fruit with significantly higher Ca concentrations compared to other treatments. / AFRIKAANSE OPSOMMING: Kalsium (Ca) tekorte ontstaan gewoonlik in gelokaliseerde areas in die appelvrug en ontwikkel dikwels ten spyte van voldoende totale vrug Ca. Minerale analises van heel vrugte verskaf dus nie genoeg inligting aangaande die verspreiding van Ca in die vrug wanneer die ontwikkelling van fisiologiese defekte soos bitterpit ter sprake is nie. Addisionele Ca word gewoonlik aangewend as blaar- of grondtoedienings, waar grondtoedienings tipies voor-oes (net na set) of in die na-oes periode, toegedien word. Die bydraes van die verskillende toedieningsmetodes tot die totale Ca konsentrasie van "Braeburn" appels is geëvalueer oor drie agtereenvolgende seisoene. Blaartoedienings van Ca word algemeen gebruik om die voorkoms van bitterpit te beheer en die Ca konsentrasie van die vrug te verhoog. Die effektiwiteit van `n reeks blaartoedienings-produkte om hierdie faktore te verbeter, is ook ondersoek. Die spesifieke verspreiding van die Ca in die vrug is gekarteer na gelang van elke toediening deur middel van PIXE-analises (Particle induced X-ray emission).
In die "Braeburn" proef was daar geen beduidende verskille in terme van vrug Ca konsentrasie op 80 dnvb (dae na volblom) nie. Daarteenoor, was daar wel beduidende verskille by 80 dnvb toe grond toedienings saam met aktiewe wortelgroei geskied het (visuele inspeksie). Weeklikse blaartoedienings vanaf 21 dnvb het gelei tot vrugte met betekenisvol hoër Ca konsentrasies as die behandeling waar grondtoedienings slegs voor-oes geskied het (Januarie 2010). `n Moontlike oorsaak vir die oneffektiwiteit van voor-oes grondtoedings is die vroeë disintigrasie van xileem vesels in die vrug (soms voor 40 dnvb en voor die aanvang van wortelopname) in sensitiewe kultivars soos "Braeburn". Hierdie vroeë inhibering van Ca voorsiening, tesame met die vroeë inisiasie van bitterpit, beklemtoon die belangrikheid van blaarbespuitings vroeg in die seisoen. Die PIXE-analises wat aangewend is om die radiale verspreiding van Ca in die vrug te bepaal het getoon dat Ca meestal in die skil en kern van die vrug gekonsentreer was, met baie lae konsentrasies in die buitenste korteks. Die laagste Ca konsentrasies is waargeneem in vrugte van die behandeling waar voor-oes Ca slegs as `n grondtoediening geskied het. Hierdie waarneming is in ooreenstemming met die mineraalanalise resultate. Ca verykte areas, afkomstig van die naby geleë vaatbundels (xileem vesels), het egter die grootste effek op vrug Ca konsentrasie gehad. Hierdie effek was nie so groot by oes nie en beklemtoon dus die belangrikheid van die funksionaliteit van die vaatbundels. Blaartoedienings kon die Ca konsentrasie in die buitenste korteks suksesvol verhoog - waar simptome van bitterpit tipies voorkom.
Die Calflo™ behandeling het beduidende hoër Ca konsentrasies gehad as die Foliar GS™ en GG™ behandelings. Die Calflo™ en Calcimax™ behandelings het `n hoër aktiewe Ca persentasie (12%) relatief tot die Foliar GS™ en GG™ (10%) behandelings bevat. Die byvoeging van Lecithin™ by Calcimax™ word nie aanbeveel nie, omdat dit geensins Ca opname vermeerder het nie.
In die "Golden Delicious" proef het die kommersiële behandeling (Sewe weeklikse spuite van Calcinit™) gelei tot vrugte met die hoogste Ca konsentrasie van al die behandelings.
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Studies towards understanding sunburn in applesMakeredza, Brian 12 1900 (has links)
Thesis (MScAgric)--Stellenbosch University, 2011. / ENGLISH ABSTRACT: Research was carried out to increase the current knowledge on sunburn development and its
control in apples. In addition to its chief causes, viz. high irradiance and high temperatures, water
stress has long been thought to contribute to sunburn susceptibility. Certain fruit chemical and
textural characteristics have also been suspected to increase sunburn, while it is not clear how
factors such as crop load affect sunburn in relation to other fruit quality parameters. In red and
blushed cultivars, sunburn could be underestimated due to masking by the red colour overlay.
Half and total irrigation water were withheld for two weeks in ‘Cripps’ Pink’ apples while in a
concomitant trial, mulching with vermicompost (plus a thin layer of woodchips), woodchips,
plant compost and black geotextile were used to regulate plant water by reducing soil
evaporative loss. Sunburn increased with an increase in moisture stress. Mulching had no effect
on plant water status, but it generally enhanced plant photochemistry, reducing fruit surface
temperature (FST) and sunburn.
Chemical and textural characteristics of exposed, but non-burned ‘Cripps’ Pink’ apples were
compared with that of fruit with induced and naturally occurring sunburn. Flesh firmness, total
soluble solids (TSS), and titratable acidity (TA) of induced and naturally occurring sunburnt fruit
did not differ from each other, but were significantly different from the non-burnt fruit. Based on
this, we concluded that sunburn induces textural and compositional changes in sunburnt fruit
rather than some fruit being predisposed to develop sunburn due to their texture and chemical
composition. Differences in heat stress tolerance, flesh texture and chemical composition of sun
exposed and shaded fruit sides seem to relate to their light exposure history. The effect of crop load on sunburn and fruit quality were assessed on a fruit cluster level in
2008-09 and on a whole tree basis in 2009-10 in ‘Cripps’ Pink’. In 2008-09, sunburn, red colour
and the proportion of first grade fruit decreased with an increase in number of fruit per cluster.
Crop load did not have an effect on sunburn and fruit colour in 2009-10 although the lowest
thinning severity seemed to increase sunburn severity while the proportion of first grade fruit
was highest for the highest thinning severity. Fruit number per cluster had no effect on fruit size,
while at the whole tree level, fruit size decreased with increasing crop load. Flesh firmness,
starch breakdown, TA and TSS were neither affected by the number of fruit per cluster nor the
crop load of the tree as a whole.
Green ‘Granny Smith’ and ‘Golden Delicious’, blushed ‘Royal Gala’, ‘Fuji’, ‘Braeburn’ and
‘Cripps’ Pink’, and full red ‘Topred’ were used to assess how red colour (anthocyanins) masks
superficial sunburn browning and bleaching. The greater reduction in superficial sunburn, but not
in sunburn necrosis in red and blushed compared to green cultivars with increasing red colour a
month towards harvest seemed to confirm the effect of masking. / AFRIKAANSE OPSOMMING: Hierdie navorsing is verrig ter uitbreiding van die huidige kennis oor die ontwikkeling en beheer
van sonbrand in appels. Addisioneel tot die hoof oorsake van sonbrand, naamlik hoë irradiasie
en hoë temperatuur, word waterstres gesien as bydraend tot sonbrandsensitiwiteit. Daar word
ook vermoed dat sekere chemiese en teksturele eienskappe van die vrug sonbrand kan verhoog
terwyl daar nie duidelikheid is oor hoe faktore soos oeslading sonbrand relatief tot ander
vrugkwaliteitparameters kan affekteer nie. Die omvang van sonbrand in rooi en bloskultivars
kan dalk onderskat word vanweë maskering deur die oorliggende rooi pigmentasie.
Besproeiing is vir twee weke gehalveer of gestop in ‘Cripps’ Pink’ appels. Sonbrand het
toegeneem met ‘n toename in vogstres. ‘n Deklaag van vermikompos (plus ‘n dun laag
houtstukkies), houtstukkies, plantkompos en ‘n swart geotekstiel is toegedien om die plant
waterstatus te reguleer deur evaporasie vanuit die grond te beperk. Die deklae het geen effek op
die plant waterstatus gehad nie, maar het wel die blaar fotochemie bevorder en terselftertyd die
vrugoppervlaktemperatuur verlaag en sonbrand verminder.
Die chemiese en tekturele eienskappe van sonligblootgestelde ‘Cripps’ Pink’ appels sonder
sonbrand is vergelyk met vrugte met geïnduseerde sonbrand en vrugte met sonbrand wat
natuurlik ontwikkel het. Vrugvleisfermheid, totale oplosbare vastestowwe (TOV) en titreerbare
suur (TS) van vrugte met natuurlik en geïnduseerde sonbrand het nie onderling verskil nie, maar
het wel betekesnisvol verskil van vrugte sonder sonbrand. Ons het gevolglik afgelei dat
sonbrand teksturele en komposisionele veranderinge teweeg bring eerder as dat sekere vrugte gepredisponeer word om sonbrand te ontwikkel vanweë hul tekstuur en chemiese samestelling.
Dit kom voor dat verskille in hittestres toleransie, tekstuur en chemiese samestelling tussen die
sonligblootgestelde en skadu kante van appels verband hou met hul verskil in sonligblootstelling.
Die effek van oeslading op sonbrand en vrugkwaliteit in ‘Cripps’ Pink’ is ge-evalueer op
trosvlak in 2008-09 en op ‘n per boom basis in 2009-10. Sonbrand, rooi kleur en die proporsie
eersteklas vrugte het afgeneem met ‘n toename in die aantal vrugte per tros. Op ‘n per boom
basis is rooi kleur en sonbrand egter nie deur oeslading geaffekteer nie. Die laagste vlak van
vruguitdunning het wel oënskynlik die graad van sonbrand verhoog terwyl die hoogste vlak van
vruguitdunning tot ‘n toename in die proporsie eersteklas vrugte gelei het. Die aantal vrugte per
tros het geen effek op vruggrootte gehad nie terwyl vruggrootte afgeneem het met oeslading op
‘n heelboombasis. Vrugvleisfermheid, styselafbraak, TOV en TS is nie deur aantal vrugte per
tros of die oeslading per boom geaffekteer nie.
Groen ‘Granny Smith’ en ‘Golden Delicious’, rooiblos ‘Royal Gala’, ‘Fuji’, ‘Braeburn’ en
‘Cripps’ Pink’, en volrooi ‘Topred’ is gebruik om die maskering van oppervlakkige
sonbrandverbruining en –verbleiking deur rooi antosianien te bestudeer. Oppervlakkige
sonbrand het minder toegeneem in die maand voor oes in die rooi- en bloskultivars as in die
groen kultivars terwyl vrugkleur skynbaar nie die aanwesigheid van die meer sigbare
sonbrandnekrose geaffekteer het nie. Maskering speel dus ‘n rol in die aanwesigheid van sigbare
sonbrand.
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