| Effect of soil nutritional status and irrigation on plant available water of wheat (Triticum aestivum L.) | Annandale, J. G. | 1989 |
KeywordsIrrigation, phosphorus, plant available water, potassium AbstractPlant available water (PAW) is the amount of water in the soil profile available for crop use. When irrigation management is based on a percentage depletion of PAW accurate estimates of PAW are essential and it is important that factors affecting the magnitude of PAW are taken into account. The effect of fertilization and irrigation on PAW of wheat was investigated in the long-term fertilization and irrigation experiment of the University of Pretoria. In situ PAW determinations revealed large differences between treatments, with well fertilized wheat being able to extract more water from the profile than nutrient deficient wheat. Reduced water supply also tended to increase PAW. Differences were attributed to the effect of the treatments on rooting depth and density. Results show that certain managerial practices such as irrigation scheduling and fertilization can influence PAW, which accentuates the need for in situ determinations rather than laboratory determinations of PAW where accurate estimates are needed. AuthorsAnnandale, J. G., Nel, A. A. and Nel, P. C. Year Published1989 PublicationSouth African Journal of Plant and Soil LocationsDOI10.1080/02571862.1989.10634489 This article contributed by:
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| Effect of soil fertility on the vegetative growth, yield and water use of wheat (Triticum aestivum L.) | Annandale, J. G. | 1984 |
KeywordsLeaf area duration, soil fertility, Triticum aestivum(L.), water-use efficiency, wheat AbstractWell-fertilized wheat was found to use more water than wheat on poorly fertilized plots, but the yield was increased, resulting in increased water-use efficiency. Variations in leaf area duration after anthesis accounted for 81% of the variation in yield. AuthorsAnnandale, J. G., Hammes, P. S. and Nel, P. C. Year Published1984 PublicationSouth African Journal of Plant and Soil LocationsDOI10.1080/02571862.1984.10634118 This article contributed by:
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| FAO-type crop factor determination for irrigation scheduling of hot pepper (Capsicum annuum L.) cultivars | Annandale, J.G. | 2009 |
Keywordsbasal crop coefficient, crop coefficient, crop evapotranspiration, crop model, SWB model AbstractAbstract Hot pepper (Capsicum annuum L.) is an irrigated, high value cash crop. Irrigation requirements can be estimated following a FAO crop factor approach, using information on basal crop coefficients (Kcb), crop coefficients (Kc) and duration of crop growth stages. However, this information is lacking for hot pepper cultivars differing in growth habit and length of growing season under South African conditions. Detailed weather, soil and crop data were collected from three field trials conducted in the 2004/05 growing season. A canopy-cover based procedure was used to determine FAO Kcb values and growth periods for different growth stages. A simple soil water balance equation was used to estimate the ETc and Kc values of cultivar Long Slim. In addition, initial and maximum rooting depth and plant heights were determined. A database was generated containing Kcb and Kc values, growing period duration, rooting depth, and crop height for different hot pepper cultivars, from which the seasonal water requirements were determined. The length of different growth stages and the corresponding Kcb values were cultivar and growing condition dependent. The database can be used to estimate Kcb and Kc values for new hot pepper cultivars from canopy characteristics. The Soil Water Balance (SWB) model predicted the soil water deficits to field capacity and fractional canopy cover well, using the FAO crop factor approach. AuthorsAnnandale, J.G., Steyn, J.M. and Alemayehu, Y.A. Year Published2009 PublicationSouth African Journal of Plant and Soil LocationsDOI10.1080/02571862.2009.10639953 This article contributed by:
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| Frodo and Darius: South African potato cultivars with good processing quality | Annandale, J.G. | 2009 |
KeywordsFry colour, reducing sugar, specific gravity, tuber characteristics AbstractTwo newly released South African potato cultivars, Frodo and Darius, were compared with two foreign processing cultivars, Pentland Dell and Shepody. The cultivars were grown under sprinkler irrigation and evaluated for external and internal tuber characteristics and processing quality. The experiment was conducted at Bronkhorst-spruit, South Africa. Results indicated that Frodo had significantly higher tuber form index values (long tuber shape) for all tuber sizes, a desired characteristic for french fry processing. Pentland Dell and Shepody exhibited more vascular discolouration, while Frodo had the highest occurrence of tuber brown spot. These physiological disorders probably resulted from unfavourably high temperatures and water stress during the late growing season. Shepody had the lowest specific gravity, followed by Pentland Dell. Reducing sugar levels for both the foreign cultivars were also relatively high and only marginally within the ranges required for french fry processing. Frodo and Darius, on the other hand, had high specific gravities and low reducing sugar levels, which are desirable characteristics for long-term storability and the production of quality frozen fries. Tuber yields of these two cultivars were also similar or higher than those of the foreign cultivars. Frodo and Darius can, therefore, successfully compete with Shepody and Pentland Dell as processing cultivars under local conditions. AuthorsAnnandale, J.G., Steyn, J.M., Geremew, E.B. and Steyn, P.J. Year Published2009 PublicationSouth African Journal of Plant and Soil LocationsDOI10.1080/02571862.2009.10639928 This article contributed by:
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| Identification of leaf rust resistance genes in Triticum species for transfer to common wheat | Antonov, A. I. | 1996 |
KeywordsPuccinia recondita f. sp. tritici, wide hybridization AbstractA total of 877 Triticum accessions (27 species) were screened for resistance to leaf rust (Puccinia recondita f. sp. tritici) using mixed inoculum of pathotypes UVPrt2, UVPrt3, UVPrt8, UVPrt9 and UVPrt13. Of these, 206 accessions were resistant/moderately resistant to all races. An attempt was made to cross each resistant accession with common wheat and to determine if resistance is expressed sufficiently in the presence of wheat genomes. Seventy nine accessions have not yet been crossed successfully, while the remaining 127 (representing 19 species) were crossed with common wheat. A number of transfer attempts failed in the F, as a result of suppression of resistance (44 accessions) or formation of embryoless or non-viable seeds/seedlings (13 accessions). The resistance of 70 hybrids is fully expressed and these are now in various stages of back-crossing to wheat. The resistance was confirmed by retesting the species sources of the 70 successful combinations with the individual leaf rust pathotypes. AuthorsAntonov, A. I. and Marais, G. F. Year Published1996 PublicationSouth African Journal of Plant and Soil LocationsDOI10.1080/02571862.1996.10634376 This article contributed by:
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| Bagworms (Lepidoptera: Psychidae): potential pests of guayule (Parthenium argentatum Gray) plantations in southern Africa | Appleton, M. R. | 1992 |
KeywordsEumeta hardenbergi, guayule, Parthenium argentatum, pest, Psychidae AbstractLarvae of the bagworm Eumeta hardenbergi (Bourgogne) (Lepidoptera: Psychidae) are reported for the first time to feed on the leaves and bark of guayule (Parthenium argentatum Gray) plants which were being examined as a potential source of natural rubber in Pietermaritzburg, Natal, South Africa. Plant damage due to the removal of stem shoots for bag construction by a light infestation of larvae was assessed. Subsequent losses in rubber yield were estimated to be c. 100 kg ha−1. An unidentified bagworm was also found feeding on guayule leaves. Both species of bagworm should be considered as potential pests of guayule plantations in areas of southern Africa. AuthorsAppleton, M. R. and van Staden, J. Year Published1992 PublicationSouth African Journal of Plant and Soil LocationsDOI10.1080/02571862.1992.10634621 This article contributed by:
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| Morphological characters and ascorbic acid content of an elite genotype of Corchorus olitorius: the influence of moisture stress | Ashafa, Anofi OT | 2013 |
Keywordsascorbic acid, Corchorus olitorius, elite genotype, harvest age, moisture stress, morphological characters AbstractMoisture stress can be deleterious to physicochemical properties of crop species to a varying degree. The influence of moisture stress on the ascorbic acid content in the leaf and morphological characters of an elite genotype of Corchorus olitorius were tested in a glasshouse experiment. The experiment was arranged in a completely randomized design replicated four times. The results of the study showed that a distinct moisture-stress threshold, described as heavy moisture stress, existed for the genotype and ascorbic acid accumulation in the leaves decreased by up to 88.7% because of moisture stress. A comparison of the control with heavy moisture stress showed a decline of 57.1% and 68.4% for plant height and number of leaves, respectively. A degree of resilience of C. olitorius to moisture stress was observed with increasing plant age, but with a significant trade-off in the nutritional quality of the genotype at harvest. AuthorsAshafa, Anofi OT, Abass, Abidemi A, Osinaike, Titilola and Lewu, Francis B Year Published2013 PublicationSouth African Journal of Plant and Soil LocationsDOI10.1080/02571862.2013.811300 This article contributed by:
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| Variability among barley landraces in response to waterlogging stress in the greenhouse | Assefa, A. | 2007 |
KeywordsBarley, dry matter, nutrients, waterlogging AbstractBarley production, in some parts of the Ethiopian central highlands, is constrained by seasonal waterlogging. The aim of this study was to investigate differences in growth, nutrient uptake and concentration under waterlogging stress between landraces varying in tolerance. A three week waterlogging treatment was done in the greenhouse and was compared with a free drainage treatment. Waterlogging reduced the total number of tillers per pot of the tolerant landraces Mage and Feleme by 43% and 48%, respectively compared to the control plants while a 23% reduction was seen for the susceptible landrace Feres Gama. Total shoot dry matter accumulation under waterlogged conditions was comparable for all three landraces. Tillers produced by Feres Gama had significantly less dry matter than Mage and Feleme, however. Differences between the susceptible and tolerant landraces in response to waterlogging were largely due to less dry matter accumulation of the tillers and slower growth in the susceptible landrace. Moreover, apparent differences were noticed in N concentration and uptake between the tolerant and susceptible landraces, the effect being less for the tolerant than the susceptible landraces. Difference in N concentration of shoots between the tolerant and susceptible landraces was also observed, though not comparable to that observed in P. AuthorsAssefa, A. and Labuschagne, M. T. Year Published2007 PublicationSouth African Journal of Plant and Soil LocationsDOI10.1080/02571862.2007.10634808 This article contributed by:
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| Methods of presenting intercropping results and preliminary results with Zea mays and Phaseolus vulgaris | Austin, M. N. | 1987 |
KeywordsCompetition, replacement intercropping AbstractReplacement intercropping trials with maize and dry beans were conducted to provide information which could lead to a cropping strategy that would reduce the risk of rainfed crop production in the Ciskei. Attention is focused on the problem of analysing intercropping experiments. It was concluded that more than one method of analysis was necessary. The gross yields obtained as well as the competition effects in terms of the proportion harvested rather than the proportions sown must be examined. Replacement intercropping of maize and beans does not appear to provide a strategy for reducing the risk of rainfed cropping in Ciskei. AuthorsAustin, M. N. and Marais, J. N. Year Published1987 PublicationSouth African Journal of Plant and Soil LocationsDOI10.1080/02571862.1987.10634226 This article contributed by:
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| Effect of irrigation scheduling on leaf yield of non-heading Chinese cabbage (Brassica rapa L. subsp. chinensis) | Averbeke, W.
van | 2010 |
KeywordsCanal irrigation, consumptive water use, leafy vegetable, smallholder schemes, South Africa AbstractA field experiment conducted on the Dzindi canal irrigation scheme in the north of South Africa demonstrated that non-heading Chinese cabbage (Brassica rapa L. subsp. chinensis) needed to be irrigated at least twice per week to maintain the water content of the rooting zone close to field capacity and achieve maximum leaf yield. Irrigation scheduling practice affected both total consumptive water use and leaf yield of the crop and the latter two variables were strongly correlated (r = 0.91). Single applications of 20 mm per week, commonly practiced by smallholders on canal irrigation schemes in the region, limited yield to about two-thirds of the maximum achieved when the soil was irrigated to field capacity every other day. Pre-charging the upper 800 mm of the soil profile to field capacity followed by single applications of 20 mm per week increased yield, but only to 80% of the maximum, suggesting that the scope for improving water use efficiency in non-heading Chinese cabbage through the use of deficit irrigation was limited. AuthorsAverbeke, W.
van and Netshithuthuni, C. Year Published2010 PublicationSouth African Journal of Plant and Soil LocationsDOI10.1080/02571862.2010.10640001 This article contributed by:
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