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

[摘要] English: In arid and semi-arid regions of South Africa, both subsistence and commercial farmersexperience economic pressure due to varying prices of staple crops such as maize andwheat as well as weather uncertainties. The prickly pear, Opuntia ficus-indica, is analternative 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 extremeweather conditions, including severe drought. Further, its economic potential per hectarefar exceeds that of maize and wheat. This supplied a rationale for investigating new waysfor manipulating the crop with the aim to increase either fruit yield and quality or newcladode production or both, by applying natural bio-stimulants as foliar sprays to adultplants while standard management practices were adhered to.ComCat® (CC), a commercially available natural bio-stimulant known for its potential tostimulate yield, growth and development in some crop plants, along with SS, a prototypenatural bio-stimulant still in the developmental phase, was used in this study in anattempt to reach the set objectives. Kelpak®, a commercially available bio-stimulant alsoknown for its growth stimulating properties, was used as a positive control. Although, inthe two trials conducted, the results were not consistent as far as all measured parametersare 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 whilethe SS treatment consistently contributed to elevated new cladode production in bothtrials.When fruit and new cladode yield data was expressed per old cladode, a different picturearose. This prompted the need to correlate the relationship between morphological andyield data. Subsequently, multiple regression and correlation analyses were performedusing morphological parameters such as fruit-, peel- and pulp mass as well as fruitdiameter and length to predict fruit yield and quality. Although the linear equationmodels resulting from this statistical calculation did not consistently show significantprediction accuracy at the 95% probability level, it was a worthwhile exercise as definite correlations were observed at least at the 90% probability level. Prediction modelsresulting from multiple regression and correlation analyses of morphological, yield andquality data strongly indicated that this approach might become a handy tool for farmersassisting them in managing their orchards not only in a specific growing season butespecially 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 withComCat® and manipulation of new cladode production by treatment with SS, can becomeadditional techniques to optimize the productivity of this crop plant.

[发布机构] University of the Free State