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Articles published from 1984-2014.

Description

Publishes original articles and commentaries on research in the fields of fundamental and applied soil and plant science. Original research papers, short communications including germplasm registrations, relevant book reviews, commentaries on papers recently published and, exceptionally, review articles will be considered for publication in the Journal. Manuscripts considered will address aspects of: Agronomical and Horticultural research including breeding and genetics, cultivar evaluation, management, nutrition, physiology, production, and quality; Soil Science research including biology, chemistry, classification, fertility, mineralogy, pedology and hydropedology, physics, and soil and land evaluation of agricultural and urban ecosystems; Weed Science research including biological control agents, biology, ecology, genetics, herbicide resistance and herbicide-resistant crops, and physiology and molecular action of herbicides and plant growth regulators; Agro-climatology; Agro-ecology; Forage, Pasture and Turfgrass science including production and utilisation; Plant and Soil Systems Modelling; Plant–Microbe Interactions; Plant–Pest Interactions; and Plant–Soil Relationships.

latest article added on October 2013

ArticleFirst AuthorPublished
Significance of kernel moisture content in determination of Hagberg Falling Number in wheatBarnard, A.2008

Significance of kernel moisture content in determination of Hagberg Falling Number in wheat

Keywords

Alpha-amylase, early harvest, Hagberg Falling Number, kernel moisture content, wheat

Abstract

The effect of early termination of kernel filling (early harvest) on the Hagberg Falling Number (HFN) was investigated over a four-year period. Selected South African wheat cultivars were harvested at different stages of kernel development, determined by kernel moisture content (KMC). HFN was determined at each stage of development. Difficulty in obtaining sufficient data points at each KMC necessitated the creation of two KMC ranges: 10–13.1% and 13.2–16.9%. Alpha-amylase activity was determined for each of the cultivars at the various KMCs during the 2003/04 and 2004/05 seasons. Data generated with three wheat cultivars (Elands, Gariep and Tugela-DN) over a four-year period indicated that the effect of KMC with harvest on the HFN of wheat is season dependant. Tugela-DN produced significantly (P≤0.05) higher HFN at the lower KMC range (10–13.1%) for two (2001/02 and 2004/05) of the four seasons during this study. Gariep showed similar results to Tugela-DN for the 2001/02 season. For Elands, the HFN remained constant over the four seasons at the various KMCs. Although there were no statistically significant differences between cultivars, it was observed that higher HFNs occurred at the lower KMC range. The effect of alpha-amylase activity at the KMC investigated in the study could not be successfully linked to reduced HFN measured at the higher KMC range. Late maturity alpha-amy-lase (LMA) was also excluded as a possible reason for reduced HFN. The current study indicated that some cultivars are prone to produce higher HFNs at lower KMCs but that the effect is limited to specific seasons.

Authors

Barnard, A., Craven, M. and Labuschagne, M.T.

Year Published

2008

Publication

South African Journal of Plant and Soil

Locations
DOI

10.1080/02571862.2008.10639898

This article contributed by:

Original

The possible role of the oxidative pentose phosphate pathway in seed dormancy in winter wheat cultivarsBarnard, A.2005

The possible role of the oxidative pentose phosphate pathway in seed dormancy in winter wheat cultivars

Keywords

OPP pathway, preharvest sprouting, seed dormancy

Abstract

Seed dormancy is an important characteristic in small grain cultivars, because of its potential to prevent preharvest sprouting and the subsequent loss of quality. In this study the oxidative pentose pathway (OPP) activity in seeds of a preharvest sprouting susceptible winter wheat cultivar, Tugela-DN and that of a preharvest sprouting resistant cultivar, Betta-DN, were compared. Carbon flux through the OPP pathway was determined both indirectly (total in vitro activity of the first regulatory enzyme, Glucose-6-phosphate dehydrogenase (G6PDH) and directly (14CO2 evolution from metabolized D-[1-14C]- and D-[6-14C]-glucose, including C6/C1 ratios). G6PDH activity increased twofold in both the harvest ripe (HR) and after ripened (AR) seeds of the susceptible cultivar during the germination phase (first 24 h of incubation) and threefold during the post germinative phase up to 72 h of incubation. The latter coincided with a high germination percentage. However, the G6PDH activity remained constant in both the HR and AR seeds of the resistant cultivar during the first 24 h of incubation and increased only slightly in the HR seeds over the remaining incubation time. Moreover, a C6/C1 ratio of below unity in seeds of Tugela-DN during the germination phase, confirmed that the OPP pathway was far more active in this preharvest sprouting susceptible cultivar than in the resistant cultivar, Betta-DN, where the C6/C1 ratio remained above unity during the germination phase.

Authors

Barnard, A. and Pretorius, J. C.

Year Published

2005

Publication

South African Journal of Plant and Soil

Locations
DOI

10.1080/02571862.2005.10634717

This article contributed by:

Original

Comparison between methods for estimating sprout damage in wheatBarnard, A.2005

Comparison between methods for estimating sprout damage in wheat

Keywords

α-amylase, falling number, sprouting, stirring number, wheat

Abstract

Sprouting in wheat is common when rain occurs during harvest. This causes the moisture content of the grain to increase to a level at which germination takes place and α-amylase increases. Various methods can be used to determine α-amylase in cereals. The Falling Number method is currently widely used in the milling and baking industry. As well as being time-tested and reliable, this method is very sensitive to the presence of low levels of enzyme. However, it is often influenced by factors other than α-amylase, such as the nature of the starch, starch damage and environment. In this study various methods to determine preharvest sprouting and α-amylase activity were compared. All the methods evaluated showed significant correlations to each other and any of these methods could therefore be used to determine sprouting. Results indicated that the Stirring Number and Falling Number methods are the most reliable for the determination of preharvest sprouting and α-amylase activity.

Authors

Barnard, A., van Deventer, C. S. and Maartens, H.

Year Published

2005

Publication

South African Journal of Plant and Soil

Locations
    DOI

    10.1080/02571862.2005.10634679

    This article contributed by:

    Original

    Productivity and stability of grain yield in wheat and maize as affected by rotational cropping systems in the eastern Free StateBarnard, A.2003

    Productivity and stability of grain yield in wheat and maize as affected by rotational cropping systems in the eastern Free State

    Keywords

    Maize, quality, rotation, wheat, yield

    Abstract

    The use of crop rotation in the Eastern Free State to enhance profitability and reduce financial risk related to mono-cropped maize and wheat, has rekindled this research. The aim of this research was firstly to quantify the effect of dry bean, lupin, sunflower and fallow on the yield of a subsequent wheat crop arid secondly, to quantify the effect of soyabean and wheat on the yield of maize. Wheat after 18 months fallow, lupin, dry bean and sunflower yielded 40, 31, 25 and 54% more than monocropped wheat. With the exception of wheat planted directly after dry bean, crop rotation reduced the variability of wheat yields. The rotational effect of sunflower on wheat appears to be unique as it simultaneously increased the yield and stability of the yield, above that of the other systems. Yield of maize grown in rotation was slightly less variable than that of the maize grown in monoculture. Crop rotation improved the protein content of maize and wheat grain, as well as the hectolitre mass of wheat.

    Authors

    Barnard, A., Nel, A. A. and Purchase, J. L.

    Year Published

    2003

    Publication

    South African Journal of Plant and Soil

    Locations
    DOI

    10.1080/02571862.2003.10634913

    This article contributed by:

    Original

    Determination of the preharvest sprouting resistance of South African winter wheat (Triticum aestivum L.) cultivarsBarnard, Annelie1997

    Determination of the preharvest sprouting resistance of South African winter wheat (Triticum aestivum L.) cultivars

    Keywords

    Dormancy, genotype × environment interaction, preharvest sprouting

    Abstract

    Preharvest sprouting significantly reduces the quality of the South African wheat crop. This study classified the preharvest sprouting resistance of 17 South African winter wheat cultivars sampled over a range of typical winter wheat growth environments. Sampling was performed under field conditions and sprouting responses were evaluated under controlled conditions. Variation in sprouting response between cultivars was predominantly genetically determined and varied from 1.7 to 7.4 on a scale from 1 (no visual sprouting) to 8 (fully sprouted). Canonical variate analysis and AMMI analysis, as well as the use of hierarchical clustering of cultivars over environments using the AMMI estimates, identified four distinct groups ranging from resistant to susceptible. The AMMI model was used as it combines the additive main effects of the analysis of variance with the interaction effects of principal components analysis. In general, Betta, and certain cultivars derived from Betta, showed good to moderate resistance to preharvest sprouting, while the hybrids Caritha and Carol, as well as the purelines Tugela and Tugela-DN, tended to be highly susceptible to sprouting.

    Authors

    Barnard, Annelie, Purchase, J. L., Smith, Marie F. and van Lill, D.

    Year Published

    1997

    Publication

    South African Journal of Plant and Soil

    Locations
    DOI

    10.1080/02571862.1997.10635073

    This article contributed by:

    Original

    Reaction of three veld grasses to different schedules of grazing and resting. 1. Patterns of shoot growthBarnes, D. L.1989

    Reaction of three veld grasses to different schedules of grazing and resting. 1. Patterns of shoot growth

    Keywords

    Grazing, resting, shoot growth patterns

    Abstract

    Seven defoliation treatments involving grazing at three-weekly intervals with sheep until mid-January or mid- March, or for the whole growing season, at each of two stocking rates, or resting for the whole growing season, were applied on veld during the 1985–86 season. Mass per unit basal area of the shoot components, green leaf, dry leaf and stem plus inflorescence of populations of tufts of the three most abundant grass species, Heteropogon contortus, Themeda triandra and Trachypogon spicatus, was determined at intervals during the periods of rest. Relative utilization was estimated by observations on samples of tufts after each grazing occasion. Within treatments, growth patterns during rest periods of the populations of the three species were broadly similar, though production per unit tuft basal area decreased in the ratio 100:65:40 for Trachypogon, Themeda and Heteropogon respectively. Using the cumulative growth curves, absolute and relative growth rates for the whole shoot and green leaf in certain of the treatments were established. A pervasive feature of the growth patterns was a tendency towards senescence in the latter half of the growing season. Defoliation by grazing was only partially effective in delaying this process. Amounts of herbage of each species which were present at the start of the rest periods beginning in mid-January and mid-March were generally proportional to the stocking pressure prior to the rest. However, within species, there was a poor correlation between this result and estimated relative utilization.

    Authors

    Barnes, D. L.

    Year Published

    1989

    Publication

    South African Journal of Plant and Soil

    Locations
    DOI

    10.1080/02571862.1989.10634471

    This article contributed by:

    Original

    Reaction of three veld grasses to different schedules of grazing and resting. 2. Residual effects on vigourBarnes, D. L.1989

    Reaction of three veld grasses to different schedules of grazing and resting. 2. Residual effects on vigour

    Keywords

    Grazing, non-structural carbohyrates, resting, root mass, vigour

    Abstract

    Seven defoliation treatments involving grazing at intervals with sheep until mid-January or mid-March, or for the whole growing season at each of two stocking intensities, or resting for the whole growing season (control treatment) were applied on veld during the 1985–86 growing season. Residual effects of the treatments on root mass and the mass of non-structural carbohydrates (NSC) in the roots of populations of the three most abundant grass species, Heteropogon contortus, Themeda triandra and Trachypogon spicatus were determined in the winter of 1986. Shoot yields in the 1986–87 growing season were measured by harvesting species separately on both a tuft basal area and quadrat basis. In general, the defoliation treatments resulted in marked reductions in root and NSC mass in all species as compared with the control. Residual effects on shoot yields were relatively small, and, in sharp contrast to previous findings, correlations between effects on roots and on shoot yields were, except in the case of Trachypogon, generally poor. Discrepancies were found between the residual effects on shoot yields of species measured on a per unit tuft basal area or a quadrat basis. The implications of such discrepancies are discussed.

    Authors

    Barnes, D. L.

    Year Published

    1989

    Publication

    South African Journal of Plant and Soil

    Locations
    DOI

    10.1080/02571862.1989.10634472

    This article contributed by:

    Original

    Variations in floristic and palatability composition, yield of veld and of soil characteristics on a paddock scaleBarnes, D. L.1987

    Variations in floristic and palatability composition, yield of veld and of soil characteristics on a paddock scale

    Keywords

    Grazing capacity, line transects, spatial variation, weighted palatability composition

    Abstract

    Five parallel 900-m line-transects were laid out 100 m apart in relatively homogeneous veld. Floristic composition, yields of dry matter, soil forms and series, effective depth, clay content of the top and subsoil, and the pH of the topsoil were determined along the transects. The floristic data were subjected to multivariate classification and ordination analyses, but no meaningful discontinuities were found. Patterns of spatial variation in palatability composition, yield and in the relevant soil characteristics were established. Taking yield and palatability composition as the primary determinants of grazing capacity, it seems from the present and previous studies that spatial variations in one or both of these parameters in local veld are commonly so great that accurate determination of patterns of distribution of grazing capacity within farms is an unrealistic objective. It is suggested that in farm planning only broad assessment of grazing capacity within relatively homogeneous veld should be aimed at. Such assessments could subsequently be refined by monitoring the condition of the veld and stock, and by the use of grazing records. There was clearly no relation between soil characteristics and floristic composition, but, to a degree, it seems that clay content of the subsoil and pH of the topsoil were negatively related to yields of grass and to a limited extent, to yields of grass plus forbs.

    Authors

    Barnes, D. L., Kotzé, G. D., Beukes, B. H. and Kohlmeyer, C.

    Year Published

    1987

    Publication

    South African Journal of Plant and Soil

    Locations
    DOI

    10.1080/02571862.1987.10634966

    This article contributed by:

    Original

    Predictive estimation of maize yield loss caused by Chilo partellus (Swinhoe) (Lepidoptera: Pyralidae) in maizeBate, Riana1992

    Predictive estimation of maize yield loss caused by Chilo partellus (Swinhoe) (Lepidoptera: Pyralidae) in maize

    Keywords

    Chilo partellus, infestation levels, infestation times, maize, yield loss

    Abstract

    The effect of Chito partellus (Swinhoe) on growth and yield of maize was investigated in two field experiments, using artificial infestation in cages. The first experiment consisted of five infestation levels, viz. 0, 15, 30, 45 and 60 eggs per plant. Plants were infested 3 weeks after emergence. The second experiment involved infestation on five occasions, viz. 2, 4, 6, 8 and 10 weeks after plant emergence, with a single infestation level of 30 eggs per plant. Results from both experiments indicated that whorl damage increased until 2 weeks after infestation, with minimal increases recorded at later stages. Levels and times of infestation were both non-linearly related to yield loss, the slope being positive for levels and negative for time of infestation. The level of whorl damage 2 weeks after infestation proved reliable for the estimation of yield losses. The economic threshold was determined as 40% plants with visible whorl damage.

    Authors

    Bate, Riana and van Rensburg, J. B.J.

    Year Published

    1992

    Publication

    South African Journal of Plant and Soil

    Locations
    DOI

    10.1080/02571862.1992.10634619

    This article contributed by:

    Original

    Yield components of samples of two wild Mexican common bean (Phaseolus vulgaris L.) populations grown under cultivationBayuelo-Jiménez, J. S.1999

    Yield components of samples of two wild Mexican common bean (Phaseolus vulgaris L.) populations grown under cultivation

    Keywords

    Phaseolus vulgaris, wild common bean, growth habit, yield components, Mexico.

    Abstract

    The common bean (Phaseolus vulgaris L.) is an annual crop legume with wild ancestors distributed from Mexico to northern Argentina. In Mexico, wild populations occur throughout this physiographically and climatically diverse country. Such a wide distribution of common bean populations suggests a large genetic variability with variants adapted to different environments with a wide range of morphological traits. In order to know the response of wild common bean to cultivation this study evaluates the yield components, actual yields and their relationship with the morphological traits, of two such wild bean populations. A sample of these populations from contrasting geographical regions, were grown together in an experimental field in the state of Mexico. They were statistically different in the expression of their growth habits. The two populations differed in leaf area, number of leaves per plant, length of main stem and number of main stem nodes, and number of pods and seeds per plant. All these differences contributed to statistically significant differences in yield. In addition, between populations with different growth habits, yield and yield components were statistically correlated with the same morphological traits. These results suggest that the differences observed in the two wild bean populations depend, at least in part, on the original habitat and that under cultivation, all these differences are likely to increase.

    Authors

    Bayuelo-Jiménez, J. S., Peña-Valdivia, C. B. and Aguirre R., J. Rogelio

    Year Published

    1999

    Publication

    South African Journal of Plant and Soil

    Locations
    DOI

    10.1080/02571862.1999.10635011

    This article contributed by:

    Original

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