Thesis (MScAgric (Horticulture))--University of Stellenbosch, 2010. / ENGLISH ABSTRACT: Creasing, also known as albedo breakdown, is a preharvest disorder that affects the albedo of citrus fruit causing creases on the surface of the fruit. It is a recurrent problem in Navel and Valencia oranges and can cause individual orchard losses which often exceed 50%. Although the contributing factors are known, the physiological basis of creasing development is unresolved and the current control measures do not prevent creasing satisfactory. Hence, better control measures and further understanding of the physiology of creasing development is required. The objective of this two-year study was to determine if the position of fruit in a tree, light and carbohydrate manipulation techniques, and albedo mineral nutrients influence creasing development. Furthermore, the most effective application timing of gibberellic acid (GA3) with the least negative effect on fruit rind colour development and the effectiveness of cytokinins, other products and different root biostimulants to reduce creasing incidence were evaluated. The position of fruit in the tree and light influenced the development of creasing and the distribution of mineral nutrients in the albedo. Creasing incidence was higher on the south side than on the north side of the tree and fruit from the inside sub-sectors had a greater creasing incidence compared to fruit from the outside sub-sectors. The shady part of outside fruit was more creased compared to the sunny part of the fruit and covering fruit with brown paper bags increased creasing severity. The light manipulation techniques used on the leaves and fruit increased the nitrogen (N), phosphorus (P), potassium (K) and manganese (Mn) concentrations in the albedo and differences in the albedo mineral nutrients amongst the sub-sectors evaluated were observed, but creasing severity or creasing incidence was not significantly correlated with the albedo mineral concentrations at harvest. Albedo mineral concentrations earlier in the season may play a role in creasing development, as creasing severity was significantly correlated with copper (Cu), K, and Mn concentrations in the albedo during stage II of fruit development. Creasing incidence and albedo mineral concentrations were not affected by any of the carbohydrate manipulation techniques used in this study. The incidence and severity of creasing was significantly reduced, with a minor negative effect on fruit rind colour development, by the application of GA3, from mid November to mid January. Localised fruit application of CPPU [N-(2-chloro-4-pyridyl)-N-phenylurea], MaxCel (6- Benzyladenine) and CPPU in combination with calcium after physiological fruit drop reduced the incidence and severity of creasing, although creasing incidence was not significantly different from the control. The application of Messenger®, AVG (aminoethoxyvinylglycine) and different root biostimulants did not reduce creasing incidence. The results showed that cytokinins could reduce creasing incidence and justify further studies on application and uptake efficiency. The use of different root biostimulants are not recommended, but it is suggested that treatment effects may be more pronounced over a longer period. / AFRIKAANSE OPSOMMING: Kraakskil is ‘n vooroes abnormalitiet wat die albedo van sitrusvrugte affekteer, deur krake op die oppervlak van vrugte te veroorsaak. Dit is ‘n algemene probleem in Navel en Valencia lemoene en kan boordverliese van tot 50% of soms hoër veroorsaak. Alhoewel die bydraende faktore bekend is, is die fisiologiese basis van kraakskil ontwikkeling onopgelos en die beskikbare beheermaatreëls is nie bevredigend nie. Dus, beter beheermaatreëls en ‘n beter begrip van die fisiologie van kraakskil ontwikkeling is nodig. Die doel van die twee-jaar studie was om te bepaal of die posisie van vrugte in ‘n boom, lig en koolhidraat manipulasie tegnieke en minerale elemente in die albedo, kraakskil ontwikkeling beïnvloed. Die mees effektiewe toedieningstyd van gibberelliensuur (GA3) sonder ‘n negatiewe effek op vrugkleur is bepaal en die effektiwiteit van sitokiniene, ander produkte en verskillende wortel biostimulante om kraakskil voorkoms te verminder, is geëvalueer. Die posisie van vrugte in ‘n boom en lig het kraakskil ontwikkeling en die verspreiding van minerale element in die albedo beïnvloed. Kraakskil voorkoms was hoër aan die suidekant van die boom as aan die noordekant en vrugte in die binnekant van die boom het ‘n groter kraakskil voorkoms as vrugte in die buitekant van die boom gehad. Die skadukant van buitevrugte het meer kraakskil gehad as die sonkant en die toemaak van vrugte met ‘n bruin papiersak het die graad van kraaksil verhoog. Die lig manipulasie tegnieke wat op die blare en vrugte gebruik is, het die stikstof (N), fosfaat (P), kalium (K) en mangaan (Mn) konsentasies in die albedo verhoog en verskille in die albedo minerale elemente tussen sub-sektore is waargeneem, maar betekenisvolle korrelasies is nie tussen die graad en voorkoms van kraakskil en die albedo minerale element konsentrasies by oestyd waargeneem nie. Albedo minerale element konsentrasies vroeër in die seisoen mag ‘n rol speel by kraakskil ontwikkeling, omdat die graad van kraakskil betekenisvol gekorreleer was met albedo koper (Cu), K, en Mn konsentrasies tydens fase II van vrugontwikkeling. Kraakskil voorkoms en albedo minerale element konsentrasies is nie deur enige van die koolhidraat manipulasie tegnieke geaffekteer nie. Die voorkoms en graad van kraakskil is betekenisvol verlaag, met ‘n geringe negatiewe effek op vrugkleur, deur die toediening van GA3 vanaf mid November tot mid Januarie. Gelokaliseerde vrugtoedienings van CPPU [N-(2-chloro-4-piridiel)-N-phenielureum], MaxCel (6- Bensieladenien) en CPPU saam met kalsium na fisiologiese vrugval het die voorkoms en graad van kraakskil verlaag, alhoewel kraakskil voorkoms nie betekenisvol van die kontrole verskil het nie. Die toediening van Messenger®, AVG (amino etoksievinielglisien) en veskillende wortel biostimulante het nie kraakskil voorkoms verlaag nie. Die resultate het getoon dat sitokiniene kraakskil voorkoms kan verlaag en verdere studies op die toediening en opname effektiwiteit word aanbeveel. Die gebruik van verskillende wortel biostimulante word nie aanbeveel nie, maar die effek behoort meer sigbaar te wees na ‘n langer periode van behandeling.

Thesis (MScAgric (Horticulture))--University of Stellenbosch, 2010. / ENGLISH ABSTRACT: Peel colour is an important quality factor in the production of bi-coloured apple fruit. Most markets set minimum requirements for red colour coverage. Fruit that do not meet these requirements are downgraded and has a major impact on the profitability of apple production in South Africa. South African apple production areas are amongst the warmest in the world. Since anthocyanin accumulation requires induction at low temperature and synthesis require mild temperatures, experiments were conducted to investigate optimum day and night temperatures for red colour development throughout fruit development for red and bi-coloured apple cultivars grown in South Africa. We found that redder strains of bi-coloured apple cultivars did not appear to owe their enhanced pigmentation to higher temperature optima for anthocyanin synthesis. The optimum day temperatures for red colour development in the different cultivars seemed to differ between seasons, but not between production areas. In general, red colour in the cultivars evaluated developed maximally between 17 ºC and 25 ºC. The optimum day temperature for red colour development remained constant throughout fruit development for most cultivars, but increased roughly from 14 ºC to 22 ºC in ‘Cripps’ Pink’ between January and April. The extent of red colour development increased during fruit development in all the cultivars assessed. We were unable to determine optimum induction temperatures for red colour development. ‘Royal Gala’ from Ceres seemed to benefit from induction at 4 ºC while red colour in ‘Fuji’ decreased with decreasing temperature. To explain the presence of anthocyanins in immature apple fruit, we tested the hypothesis that anthocyanins protect the peel from photoinhibition and photooxidative damage during conditions of increased light stress. First we established that the rate of colour change in response to a passing cold front appears to be sufficient to provide photoprotection during a cold snap. Also in agreement with the hypothesis, ‘Cripps Pink’ peel incurred significantly more photoinhibition at low temperature (16 ºC) compared to mild (24 and 32 ºC) and high (40 ºC) temperature under high irradiance with visible light. Recovery rate was temperaturedependent, being the slowest at low temperature and increasing with temperature. The photoapparatus in ‘Cripps Pink’ peel appears to be particularly sensitive to light stress at low temperature throughout the season, with significant photoinhibition occurring even at moderate temperature (24 ºC). The sensitivity of the apple peel to photoinhibition increased throughout the season at lower irradiance levels, but remained the same at higher irradiance. In our final experiment, fruit were exposed to high irradiance at low and mild temperature before exposure to high temperature in combination with high irradiance. This was done to test the hypothesis that photoinhibition incurred during cold snaps predisposes peel to photothermal damage when temperature increases again after the cold snap. Unfortunately, due to the severity of the stress incurred in response to high temperature treatment, the results were inconclusive. / AFRIKAANSE OPSOMMING: Vrugkleur is ‘n belangrike kwaliteitsfaktor in die produksie van tweekleurappels. Die meeste markte stel minimum vereistes vir rooi kleurbedekking. Vrugte wat nie aan hierdie vereistes voldoen nie, word afgegradeer. Suid-Afrika se appel produksie areas word beskou as van die warmste ter wêreld. Antosianien akkumulasie benodig induksie by lae temperature gevolg deur sintese in lig by matige temperature. Gevolglik het swak rooi kleurontwikkeling onder plaaslike toestande ‘n groot impak op die winsgewendheid van appelproduksie in Suid-Afrika. Eksperimente is uitgevoer om die optimum dag- en nagtemperature vir rooi kleurontwikkeling tydens vrugontwikkeling vir die rooi en tweekleur appel kultivars wat in Suid-Afrika geproduseer word te bepaal. Ons het gevind dat die verhoogde pigmentasie van rooier seleksies van tweekleurappel kultivars nie aan ‘n hoër temperatuur optimum vir antosianiensintese toegeskryf kan word nie. Die optimum dag temperature vir rooi kleurontwikkeling vir die onderskeie kultivars verskil klaarblyklik tussen seisoene, maar nie tussen produksie areas nie. Oor die algemeen het kleurontwikkeling maksimaal plaasgevind tussen 17 ºC en 25 ºC. Die optimum dagtemperatuur vir rooi kleurontwikkeling het konstant gebly tydens vrugontwikkeling, buiten vir ‘Cripps’ Pink’ waar dit toegeneem het van ongeveer 14 ºC tot 22 ºC vanaf Januarie tot April. Die mate van rooi kleurontwikkeling het in al die kultivars toegeneem deur die loop van vrugontwikkeling . Ons kon nie daarin slaag om optimum induksie temperature vir rooi kleurontwikkeling vas te stel nie. Rooi kleurontwikkeling van ‘Royal Gala’ uit Ceres is moontlik bevorder deur induksie by 4 ºC, terwyl ‘Fuji’ se rooi kleur afgeneem het met ‘n verlaging in induksie temperatuur. Ten einde die teenwoordigheid van antosianien in onvolwasse appelvruggies te verduidelik, het ons die hipotese getoets dat antosianien die vrugskil beskerm teen fotoinhibisie en fotooksidatiewe beskadiging gedurende tydperke van verhoogde ligstres. Eerstens het ons bevestig dat die tempo van kleurontwikkeling in reaksie op ‘n koue front waarskynlik vinnig genoeg is om fotobeskerming te verleen. Vervolgens is gevind dat ‘Cripps’ Pink’ vrugskil aansienlik meer fotoinhibisie ervaar het by lae temperatuur (16 ºC) in vergelyking met matige (24 ºC en 32 ºC) en hoë (40 ºC) temperatuur onder hoë irradiasie met sigbare lig. Die hersteltempo was temperatuur-afhanklik; dit was die stadigste by lae temperatuur en het toegeneem met ‘n toename in temperatuur. Die foto-apparaat in ‘Cripps’ Pink’ vrugskil blyk besonder sensitief te wees vir ligstres by lae temperatuur regdeur die groeiseisoen met aansienlike fotoinhibisie by selfs matige temperatuur (24 ºC). Die sensitiwiteit van die vrugskil vir fotoinhibisie het toegeneem deur die groeiseisoen by laer ligvlakke, maar het dieselfde gebly by hoër vlakke van irradiasie. Laastens is vrugte blootgestel aan hoë irradiasie by lae en matige temperatuur voordat dit vervolgens blootgestel is aan hoë temperatuur in kombinasie met hoë irradiasie. Dit was om die hipotese te toets dat fotoinhibisie wat opgedoen word gedurende ‘n onverwagte koue periode, die skil meer vatbaar maak vir fototermiese skade sodra die temperatuur weer styg na die koue periode verby is. Ongelukkig het die hoë temperatuur stres al die behandelings tot so ‘n mate geaffekteer dat dit onmoontlik was om enige gevolgtrekkings vanuit ons resultate te maak.

Thesis (MScAgric)--University of Stellenbosch, 2002. / ENGLISH ABSTRACT: Excessive shoot growth of fruit trees may have various negative effects. These include a decrease in fruit set, fruit size, red colour and in return bloom. Cultural practices that are currently in use, such as the use of dwarfing rootstocks, girdling and pruning do not always give sufficient shoot growth control. The use of plant growth retardants, in combination with these cultural practices, offer additional possibilities. Trials were conducted to evaluate the effect of the new plant growth retardant prohexadione-calcium (P-Ca) on apple, pear and plum shoot growth. In addition, the effect of P-Ca on fruit set, fruit size, yield, fruit quality and return bloom were also evaluated. During the 1999/2000 season P-Ca was applied to full bearing twelfth leaf 'Golden Delicious' trees on M793 rootstock, twenty-sixth leaf 'Granny Smith' trees on seedling rootstock, ninth leaf 'Royal Gala' trees on M793 rootstock, seventh leaf 'Rosemarie' trees on seedling rootstock and eighth leaf 'Songold' trees on 'Marianna' rootstock in the Villiersdorp area in the Western Cape (33°59' S, 19°17' E; ca. 365 m a.s.l.; Mediterranean climate). P-Ca was applied at concentrations of 3 x 50, 4 x 50 and 3 x 67 mg.l' to the apple trees. The first application was at petal drop with no surfactant added with any of the treatments. P-Ca was applied at concentrations of2 x 62.5,125,250 and 2 x 125 mg.l" to the pear and plum trees. The first application was at petal drop and pit-hardening for the pear and plum trees respectively. Agral-90 was used as surfactant only with the first spray applied to the pear trees. During the 2000/2001 season the same 'Golden Delicious' and 'Royal Gala' trees were used as in the 1999/2000 season. Thirteenth leaf 'Granny Smith' trees on M793 rootstock in the Villiersdorp area were used. Sixth leaf 'Rosemarie' trees on BP3 rootstock, fifth leaf 'Golden Russet Bose' trees on BP3 rootstock, seventh leaf 'Forelle' trees on BP3 rootstock and 16th leaf 'Packham's Triumph' trees on seedling rootstock in the Wolseley area in the Western Cape were used. P-Ca was again applied at concentrations of 3 x 50,4 x 50 and 3 x 67 mg.l' to the apple trees. The first application in the 'Golden Delicious' and 'Granny Smith' trees was at full bloom and at petal drop in the 'Royal Gala' trees. The last application was at 45 days before harvest. No surfactant was added with any of the sprays. P-Ca was applied at concentrations of 50, 75, 150, 2 x 50,2 x 75 and 3 x 50 mg.l" to the pear trees with the first spray when 4 to 5 leaves were unfolded and the last one 45 days before harvest. Agral-90 was added as surfactant with all the pear sprays. The pear trial also included a girdling treatment. P-Ca effectively inhibited shoot growth of all three apple cultivars in both seasons. Regrowth occurred in both seasons in all the cultivars, therefore it is not clear which treatment(s) is optimal for reducing shoot growth. P-Ca increased fruit size in 'Royal Gala' in the 1999/2000 season and decreased yield expressed as kg fruit harvested 1 em trunk circumference in 'Golden Delicious' in the 2000/2001 season. This reduction in yield can be attributed to the low number of flower clusters in the spring of 2000 following P-Ca treatment in 1999. P-Ca decreased the number of developed seeds in 'Royal Gala' in both seasons and increased the number of seeds with aborted embrios in the 200012001 season. After four weeks of cold storage (± 5°C) and one week at room temperature (± 20°C), P-Ca had no effect on the occurrence of bitter pit in 'Golden Delicious'. The 'Granny Smith' trees were harvested before fruit analysis could be done in the 2000/2001 season. In pear, girdling was not effective in inhibiting shoot growth in any of the cultivars, but P-Ca proved to be an effective inhibitor of shoot growth of 'Rosemarie' and 'Golden Russet Bose', and to a lesser degree 'Packham's Triumph', but not 'Forelle'. Despite the re-growth that occurred ca. four weeks after harvest in 'Rosemarie' in the 2000/20001 season, it appears that a single high rate (250 and 150 mg.l' for the 1999/2000 and 2000/2001 seasons respectively) P-Ca application is more effective than a single low rate or multiple low rates in inhibiting shoot growth. In the 200012001 season P-Ca increased fruit set in 'Rosemarie' and 'Forelle'. In both seasons P-Ca reduced 'Rosemarie' fruit size while girdling increased 'Forelle' and 'Packham's Triumph' fruit size in 2000/2001. P-Ca increased 'Rosemarie' fruit firmness and 'Forelle' fruit colour in the 2000/2001 season and decreased the percentage of 'Packham's Triumph' fruit with cork spot. Girdling increased 'Packham's Triumph' fruit colour and TSS concentration while decreasing fruit firmness in 2000/2001. P-Ca reduced return bloom in 'Forelle' and 'Packham's Triumph' in 2001, while girdling increased 'Golden Russet Bose' and 'Forelle' return bloom. Due to poor flowering and thus low fruit number in 'Golden Russet Bose', fruit set in 2000 could not be determined and no fruit analysis could be done. In 'Songold' all four P-Ca treatments inhibited shoot growth, but the 2 x 125 mg.l' treatment were the most effective, both in terms of total shoot growth and in reduction of the re-growth that occurred ca. two weeks before the first commercial harvest date. P-Ca increased fruit firmness and decreased TSS concentration both at harvest and after four weeks of cold storage at dual temperature (10 days at -O.soC + 18 days at 7.S°C). In conclusion P-Ca is an effective inhibitor of shoot growth of the apples 'Golden Delicious', 'Granny Smith' and 'Royal Gala', the pears 'Rosemarie', 'Golden Russet Bose' and 'Packham's Triumph' and the plum 'Songold', but more work is needed to control re-growth. / AFRIKAANSE OPSOMMING: Oormatige lootgroei van vrugtebome kan verskeie negatiewe effekte tot gevolg he, insluitende 'n afname in vrugset, vruggrootte, rooi kleur en 'n verlaging in die daaropvolgende jaar se blom. Boordpraktyke soos die gebruik van dwergende onderstamme, ringelering en snoei, beheer nie altyd lootgroei doeltreffend nie. Die gebruik van groeireguleerders, in kombinasie met hierdie boordpraktyke, bied bykomende geleenthede. Proewe is uitgevoer om die effek van die nuwe groeireguleerder proheksadioon-kalsium (PCa) op appel, peer en pruim lootgroei te evalueer. Die effek van P-Ca op vrugset, vruggrootte, opbrengs, vrugkwalitiet en die daaropvolgende jaar se blom is ook geevalueer. Gedurende die 1999/2000 seisoen is P-Ca toegedien aan voldraende twaalfde blad 'Golden Delicious' bome op M793 onderstamme, ses-en-twintigste blad 'Granny Smith' bome op saailing onderstamme, negende blad 'Royal Gala' bome op M793 onderstamme, sewende blad 'Rosemarie' bome op saailing onderstamme en agste blad 'Songold' bome op 'Marianna' onderstamme in die Villiersdorp area in die Wes Kaap (33°25' S, 19°12' 0; ligging ong. 270 m.; Meditereense klimaat). P-Ca is aan die appelbome toegedien teen konsentrasies van 3 x 50, 4 x 50 en 3 x 67 mg.l' met die eerste toediening by blomblaarval. Geen benatter is by enige van die toedienings gevoeg nie. P-Ca is aan die peer- en pruimbome toegedien teen konsentrasies van 2 x 62.5, 125, 250 en 2 x 125 mg.l' met die eerste toediening by blomblaarval en pitverharding vir onderskeidelik die peer- en pruimbome. Agral-90 is as benatter gebruik slegs saam met die eerste toediening op die peerbome. Tydens die 2000/2001 seisoen is dieselfde 'Golden Delicious' en 'Royal Gala' bome gebruik as in die 1999/2000 seisoen. Derde blad 'Granny Smith' bome op M793 onderstamme in die Villiersdorp area is gebruik. Sesde blad 'Rosemarie' bome op BP3 onderstamme, vyfde blad 'Golden Russet Bose' bome op BPI onderstamme, sewende blad 'Forelle' bome op BP3 onderstamme en sestiende blad 'Packham's Triumph' bome op saailing onderstamme in die Wolseley area in die Wes Kaap is gebruik. P-Ca is weereens aan die appelbome toegedien teen konsentrasies van 3 x 50, 4 x 50 en 3 x 67 mg.l". Die eerste toediening aan die 'Golden Delicious' en 'Granny Smith' bome was by volblom en die eerste toediening aan die 'Royal Gala' bome by blomblaarval. Die laaste toediening is 45 dae voor oes gedoen. Geen benatter is met enige van die toedienings bygevoeg nie. P-Ca is aan die peerbome toegedien teen konsentrasies van 50, 75, 150,2 x 50, 2 x 75 en 3 x 50 mg.l' met die eerste toediening toe vier tot vyf blare ontvou was en die laaste een 45 dae voor oes. Agral-90 is as benatter gebruik met al die peer bespuitings. By die peer proef is ook 'n ringeleer behandeling ingesluit. In beide seisoene het P-Ca die lootgroei van al drie appel kultivars verminder. Hergroei het in beide seisoene in al drie kultivars plaasgevind. Dit is dus onduidelik watter behandeling(s) optimaal is vir lootgroei beheer. In die 1999/2000 seisoen het P-Ca 'Royal Gala' vruggrootte verbeter. In die 2000/2001 seisoen is 'Golden Delicious' opbrengs, uitgedruk as kg vrugte geoes / cm stamomtrek, verlaag. Hierdie verlaging in opbrengs kan toegeskryf word aan die lae blom aantal in die lente van 2000 wat gevolg het op die P-Ca behandeling in 1999. In beide seisoene het P-Ca die aantal ontwikkelde sade in 'Royal Gala' verminder terwyl die aantal sade met geaborteerde embrios verhoog is in die 2000/2001 seisoen. Na vier weke koelopberging (± 5°C) en een week by kamertemperatuur (± 20°C) het P-Ca geen effek op die voorkoms van bitterpit in 'Golden Delicious' gehad nie. Die 'Granny Smith' bome is in die 2000/2001 seisoen geoes voordat enige data ingesamel kon word. Ringelering het geen effek op lootgroei gehad in enige van die peer kultivars nie, maar P-Ca het lootgroei effektief beheer in 'Rosemarie' en 'Golden Russet Bose' en tot 'n mindere mate 'Packham's Triumph', maar het geen effek op 'Forelle' lootgroei gehad nie. Ten spyte van die hergroei wat voorgekom het in die 'Rosemarie' bome ongeveer vier weke na oes in die 2000/2001 seisoen, wil dit voorkom asof P-Ca toegedien teen 'n enkele hoe konsentrasie (250 en 150 mg.l' vir die 1999/2000 en 2000/2001 seisoene onderskeidelik) meer effektief was om lootgroei te beheer as 'n enkele lae konsentrasie of veelvuldige lae konsentrasies. P-Ca het vrugset in 'Rosemarie' en 'Forelle' verhoog in die 2000/2001 seisoen. In beide seisoene het P-Ca 'Rosemarie' vruggrootte verlaag terwyl ringelering 'Forelle' en 'Packham's Triumph' vruggrootte verbeter het in die 2000/2001 seisoen. P-Ca het 'Rosemarie' vrugfermheid en 'Forelle' vrugkleur verhoog in die 2000/2001 seisoen en die aantal 'Packham's Triumph' vrugte met kurkvlek verlaag. Ringelering het 'Packham's Triumph' vrugkleur en TSSkonsentrasie verhoog, maar vrugfermheid verlaag in die 2000/2001 seisoen. P-Ca het die aantal blomme in 'Forelle' en 'Packham's Triumph' verlaag in 2001, terwyl ringelering blom in 'Golden Russet Bosc' en 'Forelle' verhoog het. As gevolg van 'n lae blom- en dus vruggetal in 'Golden Russet Bosc' kon vrugset In 2000 nie bepaal word nie en geen vrugontledings kon gedoen word nie. Al vier P-Ca behandelings het lootgroei in 'Songold' beheer, maar die 2 x 12S mg.l' toediening was die effektiefste, beide in terme van totale lootgroei en in beheer van die hergroei wat ongeveer twee weke voor die eerste kommersieele oesdatum plaasgevind het. PCa het vrugfermheid verhoog en die TSS-konsentrasie verlaag, beide tydens oes en na vier weke koelopberging by dubbel temperatuur (10 dae by -O.soC + 18 dae by 7.S0C). Om saam te vat kan gese word dat P-Ca 'n effektiewe inhibeerder van lootgroei van die appels 'Golden Delicious', 'Granny Smith' en 'Royal Gala', die pere 'Rosemarie', 'Golden Russet Bosc' en 'Packham's Triumph' en die pruim 'Songold' is. Meer werk is egter nodig om die hergroei te beheer.

Thesis (MScAgric)--Stellenbosch University, 2003. / ENGLISH ABSTRACT: The table grape industry uses rapid cooling and packaging to protect grapes from desiccation and decay. Numerous packaging methods and combinations are used in the industry with each having their own advantages and disadvantages. Inferior postharvest grape quality can usually be ascribed to either deficient or excessive moisture in the carton. Berry split, decay and S02 damage are all disorders that are either caused or aggravated by wet berries in conjunction with elevated temperature. On the other hand, grapes that are exposed to desiccating conditions will develop brown stems and cause ineffective control by S02 gas generators. Moisture management is governed by perforated or non-perforated liners and/or by placing moisture absorbing materials inside the liners. To find the optimum liner perforation or moisture sheet combination, 'Thompson Seedless' and 'Red Globe' (Vitis vinifera Linnaeus) table grape quality was evaluated in various trials. The investigation of non-perforated liners compared to liners with different degrees of perforation concluded the following: Perforated liners benefit grape quality by decreasing S02 damage and berry split due to less moisture in the carton. These benefits, however, also lead to loss in quality due to increased stem desiccation and a lower S02 concentration in the packaging. The lower moisture content in the carton compensates for the lower S02 concentration, creating an environment less favourable for decay development. S02 damage and berry split decreased with an increase in degree of liner perforation, irrespective of the cultivars sensitivity to the disorder. Optimum level of perforation depends on the specific sensitivity of a cultivar to certain quality disorders and the characteristics of the quality disorders associated with a cultivar. Additionally, packing conditions such as product temperature and humidity should be considered. The specific costs associated with the advantages and disadvantages influenced by the degree of liner perforation will be the deciding factor in liner selection. The investigation of a clay-containing, moisture absorbing sheet emphasized the benefits and risks of absorbing large amounts of water within the packaging. Irrespective of using a perforated or non-perforated liner the influence of the desiccant sheet was evident throughout the trials. It benefited grape quality by lowering the incidence of berry split and S02 damage. However, decay control was impaired by the desiccant sheet, and stem desiccation was aggravated. The comparison of non-perforated liners with liners of various degrees of perforation showed the benefit of faster cooling rates of perforated liners. The various perforated liners showed little variation in airflow and cooling times. Morphological studies of various cultivars could not ascribe differences in stem condition to anatomical dissimilarities between various cultivars. It was found that 'Red Globe' had a much larger berry volume to stem weight ratio contributing to a high rate of water loss and stem dehydration. Stem visibility is high in 'Red Globe' due to the straggly, loose nature of the bunches. This heightens the perception of dry, brown stems and overemphasizes the actual severity of the disorder. / AFRIKAANSE OPSOMMING: Die tafeldruifbedryf gebruik versnelde verkoeling en verpakking om druiwe te beskerm teen uitdroging en bederf. Verskeie verpakkingsmetodes word gebruik in die industrie waarvan elkeen sy eie voor- en nadele het. Ondergeskikte na-oes kwaliteit kan gewoonlik toegeskryf word aan óf te min óf te veel vog in die karton. Korrelbars, S02 skade en bederf is almal kwaliteitsdefekte wat óf veroorsaak word, óf vererger word deur nat korrels, saam met 'n verhoging in temperatuur. In teenstelling hiermee sal druiwe wat blootgestel word aan droë toestande, bruin stingels ontwikkel en S02 beheer salook ondoeltreffend wees. Vog in verpakking word beheer deur geperforeerde of nie-geperforeerde binnesakke en/of deur vogabsorberende materiaal binne die binnesak te plaas. Om die optimum binnesak perforasie of vogabsorberende vel kombinasie te vind is 'Thompson Seedless' en 'Red Globe' (Vitis vinifera Linnaeus) tafeldruif kwaliteit ge-evalueer in verskeie proewe. Die bestudering van nie-geperforeerde binnesakke teenoor binnesakke met verskillende grade van perforasies het die volgende resultate gelewer: Geperforeerde binnesakke bevoordeel druif kwaliteit deur die vermindering van S02 skade en korrelbars weens minder vog in die karton. Hierdie voordele sal egter lei tot verlies in kwaliteit weens die vinniger uitdroging van stingels en die verlaging van S02 konsentrasie in die verpakking. Die laer vog inhoud in die karton vergoed vir die vermindering van S02 konsentrasie, omdat minder gunstige toestande vir die ontwikkeling van bederf geskep word. S02 skade en korrelbars het verminder met 'n vermeerdering van perforasies, ongeag die kultivar se sensitiwiteit vir die defekte. Optimum vlakke van perforasie is afhanklik van die spesifieke sensititiwiteit van 'n kultivar tot sekere kwaliteitsdefekte, en eienskappe van die kwaliteitsdefekte wat geassosieer word met die kultivar. Boonop moet verpakkingsomstandighede soos produktemperatuur en humiditeit ook in gedagte gehou word. Die spesifieke koste verbonde aan die voor- en nadele wat beïnvloed word deur die graad van perforasie sal die bepalende faktor wees wanneer 'n binnesak gekies word. Die bestudering van 'n klei-bevattende, vogabsorberende vel het bewys dat dit voordele en risiko's inhou om groot hoeveelhede vog te absorbeer. Ongeag die gebruik van 'n geperforeerde of nie-geperforeerde binnesak, was die invloed van die desikkante vel duidelik in al die proewe. Dit was voordelig vir druif kwaliteit deurdat dit korrelbars en S02 skade verminder het. Bederfbeheer is egter verswak deur die desikkante vel, en stingel uitdroging IS vererger. Die vergelyking van nie-geperforeerde binnesakke met verskillende grade van geperforeerde binnesakke het die voordeel bewys van vinniger verkoelinstempo's van die geperforeerde binnesak. Verskille in die graad van perforasie het 'n klein invloed gehad op die lugvloei en verkoelingstempo 's. Bestudering van verskeie kultivars kon geen morfologiese verskille uitwys wat variasie in stingelkwaliteit tussen kultivars kan verklaar nie. Dit is bevind dat 'Red Globe' 'n baie groter korrelvolume tot stingelgewig verhouding het. Stingels is meer sigbaar by 'Red Globe' weens die yl, los aard van die trosse. Dit verhoog die persepsie van droë, bruin stingels en dit oorbeklemtoon die voorkoms van die defek.

Thesis (MSc)--Stellenbosch University, 1955. / ENGLISH ABSTRACT: no abstract available / AFRIKAANSE OPSOMMING: geen opsomming

Thesis (MScAgric (Horticulture))--University of Stellenbosch, 2011. / Includes bibliography. / ENGLISH ABSTRACT: Climatic differences between production areas or seasons directly affect the rate of fruit maturation and the eating quality following storage and ripening. South African ‘Forelle’ pears are harvested at an optimum firmness of 6.4 kg and have mandatory cold storage duration of 12 weeks at -0.5°C to ensure even ripening. The firmness variable alone, however, is not a good indicator of ripening potential. Hence, various maturity variables (ethylene production, ground colour, firmness, total soluble solids (TSS) titratable acidity (TA), and starch breakdown) and their rates of change were evaluated to identify consistent maturity indices that can be reliably used in a prediction model to determine optimum harvest maturity (Chapter 2). This was then related to the ripening potential (Chapter 3) and eating quality (Chapter 4), defined by optimum ‘edible firmness’ (3.5 kg), presence or absence of astringency or mealiness. Fruit were harvested from three main producing areas: Warm Bokkeveld (WBV), Elgin and Koue Bokkeveld (KBV). Harvesting was done biweekly on five harvest dates over three successive seasons (2007-2009). At harvest, 20 of 240 fruit per block were used to determine maturity using all the mentioned parameters in order to understand their changes and behaviour pre-harvest. The remaining 220 fruit were stored at -0.5°C for three storage durations followed by ripening at 15°C. At harvest, the 2007 season’s fruit were more advanced in ground colour and were significantly softer (6.7 kg) than the 2008 (7.0 kg) and 2009 (7.1 kg) seasons. Firmness, ground colour, TSS and TA, all displayed a linear relationship with days after full bloom. For the firmness and ground colour, more than 90% and 73%, respectively, was explained by the variation in the linear model, while for the TSS and TA less than 70% could be accounted for by the model. Fruit harvested before commercial harvest (pre-optimum) in 2007 and 2009 failed to ripen to an ‘edible firmness’ when stored for eight weeks at -0.5oC plus 11 days at 15oC. In 2008, eight weeks storage was sufficient to induce ripening changes in pre-optimum harvested fruit. The development of ripening potential in the 2008 earlier harvested fruit, corresponded with a higher rate of change (3.15 µL.kg-1.h-1.day-1) in ethylene production at 15oC compared to the 2007 (1.98 µL.kg-1.h-1.day-1) and 2009 (1.87 µL.kg-1.h-1.day-1) seasons. The 2007 season fruit experienced maximum incidence of astringency (36.7%) on the first harvested fruit. In all three seasons, fruit harvested at commercial harvest time and later (optimum and post-optimum), required an eight week storage period to induce ripening. However, the eight weeks storage period developed highest mealiness. More than 40% of the last harvested fruit were mealy after eight weeks at -0.5°C plus seven days at 15°C. Mealiness significantly reduced with prolonged storage at -0.5°C. Fruit from the WBV and Elgin, warmer areas than the KBV, were more prone to mealiness. In conclusion, firmness was the most consistent variable at harvest and could be used in conjunction with ground colour to determine ‘Forelle’ harvest maturity. Furthermore, the study does not support shortening the current mandatory 12 weeks period at -0.5°C due to the higher incidence of astringency and mealiness. / AFRIKAANSE OPSOMMING: Klimaats verskille tussen produksie areas of seisoene affekteer die tempo van vrugrypwording en eetkwaliteit na opberging en rypwording direk. Suid-Afrikaanse ‘Forelle’ word ge-oes by ‘n optimum fermheid van 6.4 kg en het ‘n verpligte opbergingstydperk van 12 weke by -0.5°C om egalige rypwording te verseker. Die veranderlike ‘fermheid’ is egter nie ‘n goeie aanduiding van die rypheidspotensiaal op sy eie nie. Dus is verskeie rypheidsparameters (etileen produksie, agtergrond kleur, fermheid, total oplosbare vaste stowwe (TOVS), titreerbare suur (TS) en stysel afbraak) en die tempo van verandering ge-evalueer om konstante rypheidsverwysings te identifiseer wat met vertroue in ‘n voorspellingsmodel gebruik kan word om optimum oes rypheid te kan bepaal (Hoofstuk 2). Dit is dan in verband gebring met die rypwordingspotensiaal (Hoofstuk 3) en eetgehalte (Hoofstuk 4), wat gedefiniëer is deur “eetbare fermheid” (3.5 kg), frankheid en melerigheid. Vrugte is ge-oes uit drie, hoof verbouingsareas: Warm Bokkeveld (WBV), Elgin en Koue Bokkeveld (KBV). By oes is 20 van die 240 vrugte per blok gebruik om die vrug rypheid te bepaal, deur al die bogenoemde parameters te gebruik, om die verandering en reaksie voor oes te begryp. Die oorblywende 220 vrugte is opgeberg by -0.5°C vir drie opbergingstye, gevolg deur rypmaking by 15°C. By oes was die vrugte van die 2007 seisoen verder gevorderd in agtergrond kleur en betekenisvol sagter (6.7 kg) as die van 2008 (7 kg) en 2009 (7.1 kg). Fermheid, agtergrond kleur, TOVS en TS het almal ‘n lineêre verband getoon met dae na volblom. In geval van fermheid en agtergrond kleur, is meer as onderskeidelik 90% en 73% verklaar deur die variasie in die lineêre model, terwyl in geval van die TOVS en TS, minder as 70% deur die model verklaar kon word. Vrugte wat voor die kommersiële oes (pre-optimum) ge-oes is in 2007 en 2009, het nie daarin geslaag om ryp te word tot by ‘eetbare fermheid’ na ag weke by -0.5°C en 11 dae by 15°C nie. Daarteenoor kon vrugte wat pre-optimum ge-oes is in 2008, wel geïnduseer word om ryp te word met ag weke opbeging. Die ontwikkeling van die rypwordingspotensiaal van vrugte wat vroeër ge-oes is, stem ooreen met die hoër tempo van verandering (3.15 µL.kg-1.h-1.dag-1) in etileen produksie by 15°C in vergelyking met seisoene 2007 (1.98 µL.kg-1.h-1.dag-1) en 2009(1.87 µL.kg-1.h-1.dag-1). Die 2007 seisoen vrugte het die maksimum voorkoms van frankheid (36.7%) getoon vir vrugte van die eerste oes datum. In al drie seisoene waar vrugte wat by kommersiële oes of later (optimum en post optimum) ge-oes is, was ‘n ag weke periode van opgeberging voldoende om rypwording te inisiëer, alhoewel die ag weke opberging ook gelei tot die hoogste voorkoms van melerigheid. Meer as 40% van die laat ge-oeste vrugte was melering na ag weke opberging by -0.5°C en sewe dae by 15°C. Melerigheid is betekenisvol verlaag met ‘n verlengde opbergingsperiode by -0.5°C. Vrugte vanaf die WBV en Elgin, warmer areas as die KBV, was meer onderhewig aan melerigheid. Opsommend was fermheid die reëlmatigste veranderlike by oes en kan tesame met agtergrondkleur, gebruik word om vrugrypheid van ‘Forelle’ te bepaal. Verder het die studie nie ‘n verkorting van die huidige, verpligte 12 week opberingsperiode by -0.5°C gesteun nie, weens die hoë voorkoms van frankheid en melerigheid.

Les réseaux d’entreprises sont des formes organisationnelles conduisant à un certain nombre d’avantages pour les entreprises qui en sont membres. Pour ces dernières, cette forme organisationnelle présente l’intérêt de ne pas supprimer leur autonomie ni leur indépendance, tout en bénéficiant des avantages liés aux rapprochements inter-organisationnels. De par cette particularité, les réseaux comprennent ainsi deux niveaux organisationnels distincts mais indissociables : le niveau organisationnel des entreprises membres et le niveau organisationnel du réseau. Avant de bénéficier des avantages auxquels conduit l’organisation en réseau, il est nécessaire qu’il soit construit par les organisations qui en sont à l’origine. Dans le temps, la construction du réseau conduit à un certain renforcement de son degré de néguentropie, se traduisant par une complexification sur le long-terme. Cette complexification s’opère tout en conservant l’autonomie et l’indépendance des organisations qui en sont membres. Peu de recherches se sont intéressées à cette question de la construction des réseaux. Cette thèse propose d’y répondre un utilisant l’approche par les oppositions paradoxales (approche par les paradoxes et approche par les dialectiques), qui permet de prendre en considération l’indissociabilité du double niveau organisationnel des réseaux. Par le biais d’une étude de cas appliquée à un réseau d’entreprises dans le secteur horticole de la région angevine, nous cherchons à identifier comment les objectifs de chacun des deux niveaux organisationnels contribuent à la construction du réseau en question et au renforcement de son degré de néguentropie. / Business networks are organizational forms that lead to a number of benefits for business members. For the latter, this organizational form has the advantage of not eliminating their autonomy or their independence, while benefiting from the advantages linked to inter-organizational reconciliations. In this way, the networks thus comprise two distinct but inseparable organizational levels : the organizational level of the member companies and the organizational level of the network. Before benefiting from the advantages of networking, it is necessary that it be built by the organizations that are at the origin of it. In time, the construction of the network leads to a certain strengthening of its degree of negentropy, resulting in a long-term complexification. This complexity takes place while preserving the autonomy and independence of the member organizations. Little attention has been paid to this question of network construction. This thesis proposes to answer it using a paradoxical approach (paradoxical approach and dialectical approach), which makes it possible to take into account the indissociability of the dual organizational level of networks. Through a case study applied to a network of companies in the horticultural sector of the Angevin region, we seek to identify how the objectives of each of the two organizational levels contribute to the construction of the network in question and to the reinforcement of its degree of negentropy.

No description available.

ENGLISH ABSTRACT: The export of Japanese plums from South Africa is challenging, since most cultivars are prone to develop chilling injury (CI) when stored at low temperatures. This injury manifests as gel breakdown or internal browning in the mesocarp tissue of the fruit on removal from low storage temperature conditions, i.e. in the consumer’s fruit basket, who subsequently does not buy plums again. Loss of cell membrane integrity and oxidative stress are, respectively, the primary and secondary physiological responses to CI. The main aim of this study was to investigate changes in cell membrane composition and levels of antioxidants in plums throughout fruit development and maturation, during forced air cooling (FAC) and storage under different temperature regimes. ‘Sapphire’ (a chilling susceptible cultivar) accumulated high levels of glutathione and polyunsaturated fatty acids (PUFAs) during fruit development. Therefore, the cultivar is protected against lipid peroxidation while developing on the tree, but the high levels of PUFAs, which are easily oxidised, may cause this cultivar to be chilling susceptible when stored at low temperatures. It is suggested that the high levels of monounsaturated fatty acids (MUFAs), which are not easily oxidised, and ascorbic acid that accumulated in ‘Angeleno’ (a chilling resistant cultivar) during fruit development, render this cultivar CI resistant during long-term cold-storage. When stored at -0.5 °C, CI development increased at a higher rate, ethylene evolution rates were higher and water soluble antioxidant activity (HAA), ascorbic acid and glutathione levels, and the MUFA:PUFA ratio were lower in H2 (more mature) ‘Sapphire’ plums than H1 fruit (less mature). Therefore, concurrent with H2 fruit having lower levels of antioxidants to quench free radicals caused by chilling stress, their cell membranes were more vulnerable to oxidation due to their phospholipid fatty acid composition. H2 fruit also had higher levels of saturated fatty acids, and hence less fluid cell membranes than H1 fruit when stored at -0.5 °C. An intermittent warming (IW) regime delayed symptom appearance and reduced CI severity in plums significantly compared to storage at -0.5 °C. Fruit stored under the IW regime had a more optimal phospholipid fatty acid composition and lower membrane sterol levels under shelf-life conditions to keep the membranes fluid. It also had higher levels of HAA and lipid soluble antioxidant activity, ascorbic acid and glutathione, which rendered fruit better protected against oxidation. Elevated storage temperatures (2.5 °C to 7.5 °C) caused higher levels of lipid peroxidation or low ascorbic acid levels and poor fruit quality compared to the IW regime in ‘Sapphire’ plums. ‘Laetitia’ plums stored at 5 °C and 7.5 °C had significantly less CI than under the IW regime, but softened quicker due to higher ethylene evolution rates. ‘Sapphire’ tolerated both long and short FAC durations, but a slower initial FAC rate prevented CI manifestation and caused a higher HAA after cold-storage in this fruit. ‘Laetitia’ cooled with a slower initial FAC rate and for a longer duration resulted in the best fruit quality and had higher HAA, total phenolic, phospholipid and saturated phospholipid fatty acid concentrations during storage. / AFRIKAANSE OPSOMMING: Die uitvoer van Japanese pruime vanaf Suid-Afrika hou talle uitdagings in, want die meeste van die kultivars ontwikkel koueskade wanneer hulle by lae temperature opgeberg word. Koueskade manifesteer as gelverval of interne verbruining in die mesokarpweefsel van die vrugte wanneer die vrugte verwyder word uit die lae opbergingstemperatuuromstandighede, m.a.w. in die verbruiker se vrugtemandjie, wat nie weer pruime koop nie. Verlies aan selmembraanintegriteit en oksidatiewe druk is, respektiewelik, die primêre and sekondêre fisiologiese reaksies op koueskade. Die hoofdoel van hierdie studie was om die veranderinge in selmembraansamestelling en antioksidantkonsentrasie in pruime te ondersoek tydens vrugontwikkeling en volwassewording, tydens geforseerde lugverkoeling (GLV) en tydens opberging onder verskillende temperatuurregimes. ‘Sapphire’ (‘n koueskade sensitiewe kultivar) het hoër konsentrasies van glutatioon en polionversadigde vetsure (POV) tydens vrugontwikkeling geakkumuleer. Dié kultivar is dus voldoende beskerm teen lipiedperoksidasie tydens vrugontwikkeling aan die boom, maar die hoë konsentrasies van POVs, wat maklik oksideer, mag veroorsaak dat hierdie kultivar meer koueskadesensitief is wanneer dit by lae temperature opgeberg word. Die hoë konsentrasies van mono-onversadigde vetsure (MOV), wat nie maklik oksideer nie, en askorbiensuur wat in ‘Angeleno’ (‘n koueskade weerstandbiedende kultivar) geakkumuleer het tydens vrugontwikkeling, verleen moontlik weerstandbiedendheid teen koueskade aan hierdie kultivar tydens langtermyn koelkopbering. Tydens opberging by -0.5 °C het koueskade ontwikkeling vinniger toegeneem, was etileenvrystellingstempos hoër en die wateroplosbare antioksidantaktiwiteit (HAA), askorbiensuuren glutatioonkonsentrasies en die MOV:POV verhouding laer in H2 (meer volwasse) ‘Sapphire’ pruime as in die H1 vrugte (minder volwasse). Dus, tesame met die laer antioksidantkonsentrasies in die H2 vrugte om die vry radikale veroorsaak deur koelopbering te verminder, was hul selmembrane ook meer vatbaar vir oksidasie a.g.v. die vetsuursamestellling van hul membraanfosfolipiede. Die H2 vrugte het ook ‘n hoër konsentrasie van versadigde vetsure, en dus minder vloeibare membrane as die H1 vrugte gehad tydens opberging by -0.5 °C. Die dubbeltemperatuurregime (DT) het simptoomontwikkeling vertraag en koueskade-intensiteit betekenisvol verminder in vergelyking met pruime wat by -0.5 °C opgeberg is. Vrugte wat met die DT regime opgeberg is, het ‘n meer optimale fosfolipiedvetsuursamestelling en laer konsentrasie van membraansterole tydens gesimuleerde raklewe gehad wat meer vloeibare membrane verseker het. Hierdie behandeling het ook hoër HAA en lipiedoplosbare antioksidantaktiwiteit (LAA), askorbiensuur- en glutatioonkonsentrasies gehad wat die vrugte beskerm het teen oksidatiewe druk. Verhoogde opbergingstemperature het hoër vlakke van lipiedperoksidasie of lae askorbiensuurkonsentrasies asook swak vrugkwaliteit in ‘Sapphire’ pruime veroorsaak in vergelyking met die DT regime. ‘Laetitia’ pruime wat by 5 °C en 7.5 °C opgeberg is, het betekenisvol minder koueskade gehad in vergelyking met die DT regime, maar het vinniger sag geword a.g.v. hoër etileenvrystellingstempos. ‘Sapphire’ kon lang en kort GLV tye weerstaan, maar ‘n stadiger inisiële GLV spoed het die manifestasie van koueskade voorkom en het ‘n hoër HAA in die vrugte tot gevolg gehad na koelopberging. ‘Laetitia’ wat met ‘n stadiger inisiële GLV spoed en oor ‘n langer tyd verkoel is, het die beste vrugkwaliteit, en hoër HAA, totale fenool-, fosfolipied- en versadigde fosfolipiedvetsuurkonsentrasies as die ander behandelings tydens koelopberging gehad

In Asia, the recent rapid growth in production of higher value, more pesticide intensive, horticultural crops and inland aquatic foods in linked agri-aquatic systems poses numerous environmental, health and wider livelihood threats in these often multi-use aquatic systems. ‘Green Revolution’ technologies have enhanced food security and pesticides have been promoted, however, the sustainability of prolonged pesticide use from a functional, environmental and socio-economic perspective is increasingly questionable. Further, despite international pesticide trade agreements and country-specific legislation, illegal practices still prevail. In Thailand and Sri Lanka the influence of pesticide marketing and regulation on pesticide use and hazards was investigated. Community livelihood relationships with three very different agri-aquatic systems (in Central and Northeast Thailand and Northwest Sri Lanka), pesticide use and associated aquatic and health hazards were explored with respect to surface water use and well-being status. Quantitative and qualitative data collection methods utilised participatory community appraisals, household surveys, pesticide fate in surface waters and dietary risk assessment and modelling, key informant semi-structured interviews and stakeholder workshops, to assess these relationships. Enhanced environmental and human pesticide hazards were contributed by pesticide sales incentives and weak regulation allowing illegal practices to prevail. Preliminary risk assessments found greater aquatic and human dietary pesticide hazards within communities, with the poorest at greatest vulnerability from applying pesticide and higher dependency on threatened natural aquatic food resources. The poorest in communities were most likely to overuse pesticide in Sri Lanka and were most vulnerable to illegal practices in the pesticide industry that are often linked with unauthorised traders and credit arrangements. Most horticultural production is for fresh wholesale markets with no food safety controls, and despite growing demand for safer horticultural produce, most farmers perceive pesticides as necessary, the associated hazards low and have little knowledge of safe food production and markets. These circumstances help sustain pesticide use. Some unofficial certification and misleading labelling in the ‘safe’ fruit and vegetable sector in Thailand potentially misinforms consumers and undermines trust that may threaten pesticide reduction efforts. Good Agricultural Practice (GAP) and vegetable Integrated Pest Management (IPM) are evolving practices and techniques of producing horticultural crops with less or no pesticide, the latter sometimes through Farmer Field Schools (FFS), however, evidence of success varies. Teaching through lectures and more lengthy and costly participatory methods is evident, with the former more successful on GAP and higher educated farmers and the latter with IPM and worse-off farmers, particularly when addressed within livelihood issues as a whole. However, production scale, farmer enthusiasm, produce marketing and facilitator expertise all influence outcomes, particularly with IPM, whilst proper evaluation could improve progress. Growing rural consumer interest in organic produce offers further incentives for small to medium scale farmers to implement IPM and reduce pesticide use and hazards. As value of aquatic resources was an incentive to reducing pesticide use, particularly the most dangerous products, exploration of this component of agri-aquatic systems is another exciting prospect for empowering farming community livelihoods over established and failing fear based chemical practices. Such new practices may lead the way towards affordable and trustworthy agri-aquatic systems produce with ethical certification. Greater pesticide use savings on a wider scale come from use of efficient flat fan spray nozzles compared with conventional pesticide spray nozzles. Complementary policies and stakeholder co-operation could aid pesticide use and hazard reduction efforts. A number of recommendations arose from the research.