Agricultural Research Council Grain Crops Institute

Potchefstroom, South Africa

Agricultural Research Council Grain Crops Institute

Potchefstroom, South Africa
SEARCH FILTERS
Time filter
Source Type

Belgrove A.,Agricultural Research Council Grain Crops Institute | Belgrove A.,University of Pretoria | Steinberg C.,University of Burgundy | Viljoen A.,Stellenbosch University
Plant Disease | Year: 2011

Nonpathogenic Fusarium oxysporum endophytes from healthy banana roots were evaluated for their ability to reduce Fusarium wilt of banana (Panama disease). Isolates were identified morphologically and by using species-specific primers. Pathogenicity was confirmed by inoculating banana plantlets in the greenhouse. Nonpathogenic F. oxysporum isolates were grouped into 14 haplotype groups by polymerase chain reaction restriction fragment length polymorphism analysis of the intergenic spacer region, and representative isolates evaluated for biocontrol of F. oxysporum f. sp. cubense. In the greenhouse, 10 nonpathogenic F. oxysporum isolates were able to significantly reduce Fusarium wilt of banana. The isolate that protected banana plantlets best in the greenhouse, a nonpathogenic F. oxysporum from the root rhizosphere, and Pseudomonas fluorescens WCS 417 were then field tested. When the putative biological control organisms were tested in the field, neither the nonpathogenic F. oxysporum, P. fluorescens, nor combinations thereof reduced Fusarium wilt development significantly. A number of factors could contribute to the lack of field protection, including soil microbial and chemical composition and reduced survival of biocontrol organisms in banana roots. A lack of knowledge regarding the etiology of Fusarium wilt of 'Cavendish' banana in the subtropics and the effect of F. oxysporum f. sp. cubense race and banana cultivar in protection of banana by biocontrol organisms should be further investigated. © 2011 The American Phytopathological Society.


Steenkamp S.,Agricultural Research Council Grain Crops Institute | De Waele D.,Laboratory of Tropical Crop Improvement | De Waele D.,North West University South Africa | McDonald A.,North West University South Africa
Journal of Nematology | Year: 2016

Ditylenchus africanus affects peanut quality, which leads to downgrading of consignments and economic losses for producers. This nematode is difficult to control and host-plant resistance may be the most effective way to control it. Recently, the peanut breeding line PC254K1 has been identified as resistant to a D. africanus population from Vaalharts and will be included into the peanut breeding program. The objectives of our study were to compare the reproduction potential of D. africanus geographic populations from five different areas in the peanut production area of South Africa and to assess whether PC254K1 is resistant to all five D. africanus populations. Reproduction of the D. africanus populations was evaluated on peanut callus in growth cabinets at 218C, 288C, and 358C. The peanut cv. Sellie was included in the study as the D. africanus-susceptible reference genotype in the greenhouse and microplots. Reproduction potential of all five of the D. africanus populations was similar. Resistance of PC254K1 was confirmed to all five D. africanus populations. The resistance trait of a D. africanus-resistant cultivar developed from PC254K1 should, therefore, be sustainable over the five localities tested during this study. © The Society of Nematologists 2016.


Masango M.G.,Onderstepoort Veterinary Institute | Masango M.G.,University of Pretoria | Flett B.C.,Agricultural Research Council Grain Crops Institute | Flett B.C.,North West University South Africa | And 2 more authors.
World Mycotoxin Journal | Year: 2015

Stenocarpella maydis is one of the most prevalent ear and stalk rot pathogens of maize globally, causing reductions of grain quality and yield. Various molecular methods, including polymerase chain reaction (PCR)-based techniques and nucleotide microarrays, have been developed for the identification of S. maydis infestation in maize grain. In addition to diplodiatoxin, new metabolites, namely dipmatol, diplonine and chaetoglobosins K and L, have been isolated from S. maydis infected cultures. S. maydis infected maize is also associated with intoxication in ruminants. Diplodiosis, a nervous disorder of cattle and sheep, results from ingestion of mouldy ears, kernels and maize stubble infected by S. maydis. Although this disease is most common in southern Africa, it has also been reported in Australia, Argentina and Brazil. Diplodiosis is characterised by reluctance of the animals to move, a wide-based stance, incoordination, paralysis and death. Myelin degeneration (status spongiosis) is the only histopathological change observed in affected animals, especially in cases of perinatal mortality. To date, none of the purified S. maydis metabolites has been administered to ruminants in order to reproduce diplodiosis. However, recent studies have focused on investigating the toxicity of the metabolites on cell cultures. Cytotoxicity studies where cultured cells were exposed to the S. maydis metabolites indicated that diplodiatoxin and dipmatol affected the activity of the mitochondrial succinate dehydrogenase enzyme and the overall viability of the cells. More detailed in vitro toxicity studies are still required to elucidate how the currently available S. maydis metabolites influence parameters such as the mechanism of cell death. Development of analytical test methods to quantify and establish the presence and distribution of these mycotoxins in infected maize commodities also needs investigation. It is also critical that the role of S. maydis stalk rot be evaluated as a potential source and cause of diplodiosis. © 2014 Wageningen Academic Publishers.


PubMed | North West University South Africa and Agricultural Research Council Grain Crops Institute
Type: Journal Article | Journal: Journal of nematology | Year: 2016

Ditylenchus africanus affects peanut quality, which leads to downgrading of consignments and economic losses for producers. This nematode is difficult to control and host-plant resistance may be the most effective way to control it. Recently, the peanut breeding line PC254K1 has been identified as resistant to a D. africanus population from Vaalharts and will be included into the peanut breeding program. The objectives of our study were to compare the reproduction potential of D. africanus geographic populations from five different areas in the peanut production area of South Africa and to assess whether PC254K1 is resistant to all five D. africanus populations. Reproduction of the D. africanus populations was evaluated on peanut callus in growth cabinets at 21C, 28C, and 35C. The peanut cv. Sellie was included in the study as the D. africanus-susceptible reference genotype in the greenhouse and microplots. Reproduction potential of all five of the D. africanus populations was similar. Resistance of PC254K1 was confirmed to all five D. africanus populations. The resistance trait of a D. africanus-resistant cultivar developed from PC254K1 should, therefore, be sustainable over the five localities tested during this study.


Chiremba C.,University of Manitoba | Chiremba C.,University of Pretoria | Chiremba C.,Agricultural Research Council Grain Crops Institute | Rooney L.W.,Texas A&M University | Beta T.,University of Manitoba
Journal of Agricultural and Food Chemistry | Year: 2012

To release bound phenolic acids, a microwave-assisted extraction procedure was applied to bran and flour fractions obtained from eight sorghum and eight maize cultivars varying in hardness. The procedure was followed by HPLC analysis, and the identities of phenolic acids were confirmed by MS/MS spectra. The extraction of sorghum and maize bound phenolic acids was done for 90 s in 2 M NaOH to release ferulic acid and p-coumaric acid from bran and flour. Two diferulic acids, 8-O-4′- and 8-5′-benzofuran form, were identified and quantitated in sorghum bran, and only the former was found in maize bran. The contents of ferulic acid and diferulic acids in sorghum bran were 416-827 and 25-179 μg/g, respectively, compared to 2193-4779 and 271-819 μg/g in maize. Phenolic acid levels of sorghum were similar between hard and soft cultivars, whereas those of maize differed significantly (p < 0.05) except for ferulic acid in flour. Sorghum phenolic acids were not correlated with grain hardness as measured using a tangential abrasive decortication device. Maize ferulic acid (r = -0.601, p < 0.01), p-coumaric acid (r = -0.668, p < 0.01), and 8-O-4′-diferulic acid (r = -0.629, p < 0.01) were significantly correlated with hardness. © 2012 American Chemical Society.


Chiremba C.,University of Pretoria | Chiremba C.,Agricultural Research Council Grain Crops Institute | Rooney L.W.,Texas A&M University | Rooney L.W.,University of Pretoria | Taylor J.R.N.,University of Pretoria
Cereal Chemistry | Year: 2011

Grain hardness affects sorghum and maize processing properties especially for dry milling. A variety of simple grain quality parameters were assessed on 17 sorghum and 35 white maize hybrid cultivars grown in six and four locations, respectively, in South Africa. The purpose was to determine tests that can be used to distinguish hardness in commercial sorghum and maize. The grains were characterized by test weight (TW), thousand kernel weight (TKW), decortication with the tangential abrasive dehulling device (TADD), and kernel size. Maize was also characterized for susceptibility to breakage, stress cracking, and near-infrared transmittance (NIT) milling index. Principal component analysis showed that, in nontannin and tannin sorghums, TADD hardness and TW were closely correlated (P < 0.001). In maize, TADD hardness was closely correlated (P < 0.001) with NIT milling index and TW. Hence, TADD hardness and NIT milling index or TADD hardness and TW would be suitable for maize hardness evaluation. A combination of TADD hardness, TW, TKW, and kernel size >3.35 mm can be used together to select sorghum grain for hardness. It thus appears that TADD hardness is an excellent method of estimating both sorghum and maize hardness that can be applied for routine batch analysis and cultivar evaluation. © 2011 AACC International, Inc.


Chiremba C.,University of Manitoba | Chiremba C.,University of Pretoria | Chiremba C.,Agricultural Research Council Grain Crops Institute | Taylor J.R.N.,University of Pretoria | And 2 more authors.
Food Chemistry | Year: 2012

The role of phenolic acids on sorghum and maize hardness was evaluated among eight cultivars of each of the cereals representing hard and soft classes. Bran and flour fractions were evaluated for monomeric and diferulic phenolic acids using high performance liquid chromatographic and mass spectrometric (LC-MS/MS) techniques. Bran samples of harder grains had more phenolic acids than those of soft types. Intra-class testing showed slight differences in cultivars within the hard and soft classes. The content of phenolic acids was a useful indicator of hardness distinguishing between hard and soft maize and sorghum cultivars. Correlation coefficients between monomeric acids of maize bran, mostly ferulic acid, and grain hardness were higher than those of sorghum. Maize bran ferulic acid content was strongly correlated with Tangential Abrasive Dehulling Device (TADD) hardness (r = -0.776, p < 0.001). This study is the first to show that there is a relationship between bran phenolic acid content and sorghum and maize hardness. © 2012 Elsevier Ltd. All rights reserved.


Muedi H.T.H.,Agricultural Research Council Grain Crops Institute | McLaren N.W.,University of the Free State | Fourie D.,Agricultural Research Council Grain Crops Institute
Crop Protection | Year: 2015

Bacterial brown spot (BBS), caused by Pseudomonas syringae pv. syringae (Pss), is a disease of common beans (Phaseolus vulgaris L.) in South Africa. Planting of pathogen-free seed and application of copper-based chemicals do not guarantee disease control. Genetic resistance is considered the most effective control measure. BBS occurs regularly in major dry bean production areas. The aim of this study was to screen selected accessions for their reaction to BBS. Twenty-seven common bean accessions were assessed over three seasons and locations for resistance to BBS. Trials were arranged in a randomized complete block design with three replications and artificially inoculated with Pss (1×108CFU/mL) using a Stihl mistblower at 21, 28 and 36 days after planting. Plots were rated for disease reaction on a modified 1-9 CIAT scale with 1 being resistant and 9 being susceptible. Ratings were done at 7, 14, 21 and 28 days after the first inoculation. Trials were harvested manually and yield data were recorded. Disease ratings were used to construct the area under the disease progress curve (AUDPC). Highly significant genotype×environment interactions were recorded and additive main effects and multiplicative interaction analysis was used to identify lines in which disease response and yield were significantly affected by environment. VAX 4 and VAX 2 had lowest disease ratings of 1.8 and 2.0, and AUDPC values of 38.6 and 41.6, respectively, and are therefore potential resistance sources. © 2015 Elsevier Ltd.


Nel A.A.,Agricultural Research Council Grain Crops Institute
South African Journal of Plant and Soil | Year: 2014

Subsurface sunflower (Helianthus annuus L.) seedling growth often deteriorates on sandy-textured soils due to supra-optimal temperature levels on the Highveld area of South Africa leading to poor emergence and suboptimum plant population densities. It has been shown that seedling growth is enhanced by the application of plant growth promoting rhizobacteria and cytokinin. The possibility therefore exists that the poor emergence problem might be remedied through the use of these applicants. The objective of this investigation was to determine if commercially available bacterial-based biofertilisers and cytokinin can enhance the seedling vigour of subsurface sunflower seedlings in controlled ambient temperatures ranging from non-limiting to supra-optimal and in unregulated field conditions. The results suggest that there are conditions where bacterial-based biofertiliser and cytokinin can alleviate the damaging effect of supra-optimal temperatures on the emergence of sunflower. However, the effect of these applicants on various cultivars and soil conditions require further investigation. © 2014 © Southern African Plant & Soil Sciences Committee.


Craven M.,Agricultural Research Council Grain Crops Institute | Nel A.A.,Agricultural Research Council Grain Crops Institute
South African Journal of Plant and Soil | Year: 2016

Although crop rotation reduces the incidence of soil-borne diseases, reduced tillage practices create the risk of increased disease incidence. Monoculture maize (MM) under both conventional tillage (CT) and conservation agriculture (CA) crop systems were evaluated against two-and three-year rotation CA systems of maize with cowpea and sunflower, respectively. Pearl millet was the third crop in the three-year rotation systems. Plant mass, root and crown rot severity and frequencies of 15 soil-borne fungi on maize roots and crowns were investigated at three sampling dates, i.e. 21, 70 and 100 days after planting (DAP), together with yield. The trial was initiated during 2008/09 on a sandy loam soil in the Highveld climatic area of South Africa and the current study focused on the 2011/12, 2012/13 and 2013/14 seasons. Lower yields and plant mass at 100 DAP were obtained for the MM-CT treatment compared with MM-CA and rotated maize during the drought-stricken 2012/13 season. Yields obtained for this season correlated with crown rot severity at 100 DAP. Stenocarpella maydis and Macrophomina phaseolina correlated negatively with crown rot and plant mass at 100 DAP as well as yield (2012/13). Both fungi were most prominent in the MM-CT system. © 2016 Southern African Plant & Soil Sciences Committee

Loading Agricultural Research Council Grain Crops Institute collaborators
Loading Agricultural Research Council Grain Crops Institute collaborators