The influence of environmental factors on spineless cactus pear (Opuntia spp.) fruit yield in Limpopo Province, South Africa

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Date
2007-11
Authors
Potgieter, Johannes Petrus
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Publisher
University of the Free State
Abstract
English: Limited information is available on the response of local cactus pear cultivars to environmental factors that influence fruit yield. Eleven cultivars were evaluated in three diverse agro-climatic areas over seven production seasons in the Limpopo Province to assess their environmental adaptability. Significant differences between cultivars, areas and production years for five fruit yield components were evident. A strong genotype by environment interaction was observed, although some cultivar characteristics were genetically controlled. The most suitable production area is the cool mid-altitude area of Limpopo Province. Cultivars that can be recommended for fresh fruit production are: “Algerian”, “American Giant”, “Gymno Carpo”, “Malta”, “Morado”, “Nudosa” and “Zastron”. Fruit yield was significantly influenced by minimum temperature and plant macro nutrients. Soil phosphorus levels above 20 mg kg-1 and applied nitrogen higher than 100 kg ha-1 year-1 had a positive effect on fruit yield. Soil pH did not influence the fruit yield of the cultivars tested. None of the cultivars tested had a winter chilling requirement to become fertile. Vegetative growth was stimulated by increased solar radiation. Cactus pear plants can be considered to be fully mature from the fifth year onwards. Environmental adaptability is related to species differences rather than plant morphological differences. Plant growth habit changed markedly in different environments. To obtain high fruit yields, it is important to match a cultivar with prevailing environmental conditions of the area. Fruit yield in cactus pear is a function of the number of fertile cladodes, the number of fruit set, the number of fruit left after thinning and individual fruit mass. Research into orchard practices, in particular pruning, and evaluation of the existing cactus pear germplasm should receive attention. As a “new” cultivated fruit crop it offers real solutions towards mitigation of the effects of drought in arid and semi-arid parts of Limpopo Province.
Afrikaans: Beperkte inligting rondom die invloed van omgewingsfaktore op die prestasie van plaaslike turksvykultivars ten opsigte van vrugopbrengs is beskikbaar. Elf kultivars is in drie uiteenlopende agroklimaatomgewings oor sewe produksiejare in Limpopo Provinsie geevalueer om hul omgewingsaanpassing te bepaal. Betekenisvolle verskille tussen kulitvars, areas en produksiejare ten opsigte van vyf vrugopbrengskomponente is bevind. Alhoewel sekere kultivareienskappe geneties van aard is, is ‘n duidelike interaksie tussen genotipe en omgewing bevind. Vrugopbrengs is ‘n funksie van die aantal vrugbare kladodes, aantal vrugte op die plant na uitdunning en vrugmassa. Die koel gemiddelde hoogte bo seevlak proefperseel is bevind as die mees geskikste produksiearea. Slegs “Algerian”, “American Giant”, “Gymno Carpo”, “Malta”, “Morado”, “Nudosa” en “Zastron” voldoen aan die minimum vrugopobrengsnorme, terwyl “Blue Motto”, “Direkteur”, “Fusicaulis” en “Skinners Court” nie aanbeveel word vir vrugproduksiedoeleindes nie. . In hierdie studie is vrugopbrengs beduidend deur minimum temperatuur en voedingstofstatus van die grond, veral t.o.v. die makro- elemente beinvloed. Vrugpbrengs is positief beinvloed by fosfaatvlakke hoer as 20 mg kg -1 en toegediende stikstof hoer as 100 kg ha -1 jaar -1. Grond pH het geen effek op vrugopbrengs gehad nie. Vegetatiewe ontwikkeling is gestimuleer by verhoogde stralingsvlakke. Kultivars in die studie het geen kouebehoefte getoon nie. Volle boordvolwassenheid word reeds vanaf die vyfde produksiejaar bereik. Plantmorfologie is nie geskik om die aanpassingsvermoë van kultivars vir ‘n bepaalde agro-klimaatsarea te bepaal nie. Omgewingsaanpassingsvermoë kan eerder deur spesie as ‘n bepaalde plantmorfologieverskil bepaal word. Alhoewel dit van kardinale belang is om die korrekte kultivar vir ’n bepaalde omgewing te selekteer, kan boordpraktyke soos snoei ook gebruik word om vrugopbrengs te bevorder. Verdere navorsing is noodsaaklik om gepaste boordpraktyke te bepaal en om die volledige Suid-Afrikaanse turksvygenepoel te karakteriseer en dit in uiteenlopende omgewings van die land te evalueer vir vrugopbrengspotensiaal. Die veeldoelige turksvy is ‘n moontlike oplossing as droogte- versagtende maatreël in die ariede en semi-ariede dele van Limpopo Provinsie.
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Keywords
Dissertation (M.Sc.Agric. (Agrometeorology/Horticulture))--University of the Free State, 2007, Prickly pears -- Yields -- South Africa -- Limpopo, Prickly pears -- South Africa -- Limpopo, Prickly pears -- Environmental aspects -- South Africa -- Limpopo, Fruit yield
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