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Yield and fruit quality assessment of cactus pear (Opuntia ficus-indica (L.) Mill.) treated with natural bio-stimulants

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dc.contributor Pretorius, J. C.
dc.contributor Van Rensburg, L. D.
dc.creator Buitendag, R. A.
dc.date 2018-01-24T06:48:24Z
dc.date 2018-01-24T06:48:24Z
dc.date 2004-11
dc.date.accessioned 2018-06-24T05:29:28Z
dc.date.available 2018-06-24T05:29:28Z
dc.identifier http://hdl.handle.net/11660/7688
dc.identifier.uri http://hdl.handle.net/11660/7688
dc.description English: In arid and semi-arid regions of South Africa, both subsistence and commercial farmers experience economic pressure due to varying prices of staple crops such as maize and wheat as well as weather uncertainties. The prickly pear, Opuntia ficus-indica, is an alternative crop that can partially offer a solution to these problems as an extra income. Further, it is capable to produce both fruit and young cladodes under rather extreme weather conditions, including severe drought. Further, its economic potential per hectare far exceeds that of maize and wheat. This supplied a rationale for investigating new ways for manipulating the crop with the aim to increase either fruit yield and quality or new cladode production or both, by applying natural bio-stimulants as foliar sprays to adult plants while standard management practices were adhered to. ComCat® (CC), a commercially available natural bio-stimulant known for its potential to stimulate yield, growth and development in some crop plants, along with SS, a prototype natural bio-stimulant still in the developmental phase, was used in this study in an attempt to reach the set objectives. Kelpak®, a commercially available bio-stimulant also known for its growth stimulating properties, was used as a positive control. Although, in the two trials conducted, the results were not consistent as far as all measured parameters are concerned and were not statistically significant in all cases, ComCat® (CC) consistently contributed to a increase in the total fruit yield expressed in ton ha-1 while the SS treatment consistently contributed to elevated new cladode production in both trials. When fruit and new cladode yield data was expressed per old cladode, a different picture arose. This prompted the need to correlate the relationship between morphological and yield data. Subsequently, multiple regression and correlation analyses were performed using morphological parameters such as fruit-, peel- and pulp mass as well as fruit diameter and length to predict fruit yield and quality. Although the linear equation models resulting from this statistical calculation did not consistently show significant prediction accuracy at the 95% probability level, it was a worthwhile exercise as definite correlations were observed at least at the 90% probability level. Prediction models resulting from multiple regression and correlation analyses of morphological, yield and quality data strongly indicated that this approach might become a handy tool for farmers assisting them in managing their orchards not only in a specific growing season but especially for the following season. More research is necessary to pursue this aspect. Finally, manipulation of fruit yield in O. ficus-indica by foliar sprays of adult plants with ComCat® and manipulation of new cladode production by treatment with SS, can become additional techniques to optimize the productivity of this crop plant.
dc.description Afrikaans: In ariede en semi-ariede streke van Suid Afrika beleef beide kommersiële en bestaansboere tans ekonomiese druk weens wisselende pryse van stapelgewasse soos mielies en koring, asook die onsekerheid van klimaatsomstandighede. Die turksvy, Opuntia ficus-indica, is ‘n alternatiwe gewas wat gedeeltelik ‘n bydrae kan lewer om hierdie probleme te oorbrug, aangesien vrugpryse nie so wisselvallig is as mielie- en koringpryse nie en aangesien die gewas steeds vrugte en nuwe kladodes kan produseer onder uiterste klimaatsomstandighede, soos droogte. Verder, oortref die ekonomiese potensiaal van turksvyvrugte per hektaar dié van mielies en koring by verre. Laasgenoemde het die rasionaal verskaf om die moontlikheid van nuwe tegnieke te ondersoek ten einde die gewas só te manipuleer dat dit tot verhoogde vrugopbrengs en – kwaliteit, asook verhoogde nuwe kladode-produksie aanleiding kan gee. Ten einde hierdie doelwitte te bereik, is natuurlike bio-stimulante as blaarbespuitings op volwasse plante toegedien, terwyl standaard bestuurspraktyke gevolg is. ComCat® (CC), ‘n kommersieël beskikbare natuurlike bio-stimulant bekend vir sy potensiaal om oesopbrengs, kwaliteit asook groei en ontwikkeling in gewasse te stimuleer, tesame met SS, ‘n prototipe natuurlike bio-stimulant tans in die ontwikkelingsfase, was in hierdie studie gebruik. Kelpak®, ‘n kommersieel beskikbare bio-stimulant ook bekend vir groeistimuleringseienskappe, was as positiewe kontrole gebruik. Alhoewel die resultate in beide proewe nie deurgaans dieselfde was in terme van al die gemete parameters nie en ook nie altyd statisties betekenisvol was nie, het ComCat® (CC) bygedra tot betekenisvolle verhoging van vrug opbrengs, uitgedruk as ton ha-1 terwyl die SS behandeling deurgaans tot verhoogde kladode-produksie aanleiding gegee het. Wanneer nuwe kladode-produksie as ‘n waarde per ou kladode uitgedruk was, het ‘n nuwe tendens tevoorskyn gekom. Laasgenoemde het aanleiding gegee tot die behoefte om die verwantskap tussen morfologiese en oesopbrengsdata te korreleer. Gevolglik is meervoudige regressie en korrelasie-analises uitgevoer deur gebruik te maak van morfologiese parameters soos vrug-, skil- en vlees (“pulp”) massa asook vrugdeursnee en -lengte, om vrug-oesopbrengs en -kwaliteit te voorspel. Alhoewel die linieêre model vergelykings wat hieruit voortgespruit het nie deurgaans statisties betekenisvolle voorspellingsakkuraatheid by 95% waarskynlikheid getoon het nie, was die oefening betekenisvol in die sin dat definitiewe korrelasies op die 90% waarskynlikheidsvlak waargeneem is. Die voorspellingsmodelle wat hieruit voortgespruit het, het sterk daarop gedui dat hierdie benadering ‘n handige instrument vir turksvy-boere kan word in die bestuur van hulle boorde, nie net alleen vir ‘n spesifieke seisoen nie, maar ook met die oog op beplanning vir die opvolgende seisoen. Meer navorsing is egter nodig om hierdie aspek op te volg. Ten slotte moet beklemtoon word dat die manipulering van turksvy-plante deur blaarbespuiting van volwasse plante met ComCat®, ten einde vrugopbrengs te verhoog en manipulering van kladode-produksie deur behandeling met SS, die potensiaal besit om as addisionele tegnieke vir die optimalisering van hierdie alternatiewe gewas se produktiwiteit toegepas kan word.
dc.language en
dc.publisher University of the Free State
dc.rights University of the Free State
dc.subject Prickly pears -- South Africa
dc.subject Prickly pears -- Yields
dc.subject Foliar feeding
dc.subject Prickly pears -- Quality
dc.subject Dissertation (M.Sc.Agric. (Soil, Crop and Climate Sciences (Agronomy))--University of the Free State, 2004
dc.title Yield and fruit quality assessment of cactus pear (Opuntia ficus-indica (L.) Mill.) treated with natural bio-stimulants
dc.type Dissertation


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