Theses and Dissertations

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Open Access
Agronomic evaluation of chickpea (Cicer arietinum L.) genotypes in contrasting agro-ecological regions of Limpopo and Mpumalanga Provinces
(2020-02-24) Shilenge, Siphiwe Kim; Ogola, J. B. O.; Odindo, A.
Chickpea (Cicer arietinum L.) is an important grain legume in the world, ranking second after soybean (Glycine max L.). It accounts for a substantial proportion of human dietary nitrogen intake and plays a crucial role in food security in developing countries. Chickpea can grow in areas with low rainfall and poor soils, and thus may be an important food security crop for smallholder resource-poor farmers in the semi-arid tropics such as the dry environments of the Limpopo and Mpumalanga Provinces of South Africa. Preliminary studies showed the huge potential of chickpea production in these environments. However, no suitable genotypes have been identified and recommended for different agro-ecological zones of Limpopo and Mpumalanga Provinces. Therefore, the objective of this study was to evaluate the performance, and hence, identify the genotypes that are adapted/suitable to the contrasting agro-ecological conditions of Limpopo and Mpumalanga Provinces for production. Field experiments were conducted in the winter cropping seasons of 2016 and 2017 at Thohoyandou (University of Venda experimental station), Syferkuil (University of Limpopo experimental station) and Nelspruit (University of Mpumalanga experimental station). Ten desi chickpea genotypes were sown in a completely randomized block design replicated three times on 10 May 2016 and 10 April 2017 (Thohoyandou), 13 May 2016 and 11 April 2017 (Syferkuil) and 03 May 2016 and 24 May 2017 (Nelspruit). Plant growth characteristics were assessed by determining plant height, crop phenology, number of primary and secondary branches, and canopy cover. Yield and yield components were assessed at harvest after physiological maturity. Carbon dioxide exchange rates (CER) was determined at different growth stages using the InfraRed Gas Analyzer (IRGA). Chlorophyll content (CC) and intercepted radiation were determined weekly using the chlorophyll content meter (CCM-200 PLUS, Opti-Science, Tyngsboro, Massachusetts), and the AccuPAR, LP-80 ceptometer (Deacon Devices Ltd., Pullman, USA), respectively. Genotypes did not vary in CC at Thohoyandou in all seasons, but CC increased with stages of growth. Genotypes varied in the proportion of intercepted radiation (IR) at all measurement dates in Thohoyandou during the 2016 and 2017 growing seasons. The proportion of IR increased with growth stage, reached a peak and declined with plant age. Genotype affected photosynthesis and intercellular CO2 concentration (Ci) but did not have any significant effect on stomatal conductance (gs), transpiration (T) and Leaf Vapour Pressure Deficit (VPDL) during the 2016 season in Thohoyandou. In contrast, genotype did not affect photosynthesis, Ci, gs, T and VPDL in the 2017 season in Thohoyandou. There was no variation among genotypes on number of primary and secondary branches in Thohoyandou in both seasons. Genotypes showed no variation in plant height in the 2016 season in Thohoyandou agro-ecological condition. However, genotypes showed significant variation in plant height at 14, 70 and 84 days after emergence (DAE) in the 2017 cropping season. Moreover, genotypes showed significant variations in days to 50% flowering in Thohoyandou during the 2016 season, but showed no variations in days to 50% emergence and 75% physiological maturity. Genotypes showed no variations in days to 50% emergence, 50% flowering, 50% podding and 75% physiological maturity in the 2017 season in all locations. Genotypes showed significant variation in grain yield in Syferkuil agro-ecological condition, but showed no significant variations on all the other studied traits, while genotypes varied in 100 seed weight (SW) in Thohoyandou, but did not show any variations on the other studied traits during the 2016 season. Moreover, genotypes did not vary for all studied traits in Nelspruit during the 2016 season. The 2016 genotype and environment (G X E) interaction results showed no significant variations. However, results showed G X E interactions during the 2017 growing season suggesting that genotypes responded to environmental variation in a different way. Syferkuil had the greatest grain yield (2811 kg ha-1 and 3122 kg ha-1) in both the 2016 and 2017 growing seasons respectively, as compared to Thohoyandou and Nelspruit. These preliminary findings show that the studied genotypes responded differently in contrasting agro-ecological regions of Limpopo and Mpumalanga Provinces and that Syferkuil might be the best environment for chickpea production in this region due to its cooler temperatures. Of the genotypes evaluated the most promising genotypes are ICCV8101, ICCV3203 and ICCV4110 in these regions in terms of grain yield.
Open Access
Assessment of hydro-physical properties of some crusting soils in four different soil form as revealed by micro-focus x-ray computed tomography in Limpopo Province, South Africa
(2021-06-23) Mpofu, Khuthadzo Tendani Given; Wakindiki, I. I. C.; Odhiambo, J. J. O.
Most of the available knowledge about soil structure degradation through crust formation is limited to two-dimensional geometry. However, soil is a natural three-dimension body. The objective of the study is to assess soil crusting and hydro physical properties in four different soil form by using X-ray Computed Tomography, Characterizing micro-morphometric of crusting soil’s pore system, quantifying soil structure degradation through crusting development and visualizing hydro physical properties in all four-soil form. Micro X-ray Computed Tomography techniques can greatly add value to existing knowledge because they can reveal soil structure in three dimensions (3D). Undisturbed soil aggregates were obtained from two adjacent sampling locations namely Visibly Crusted (VC) and Not-Visibly Crusted (NVC). Four soil forms were studied in Limpopo province, South Africa at Vhembe Region under Thulamela and Collin Chabane local Municipality. Soil form studied are Dundee, located at (Tshamutoro village), Shortlands (Mukula Village), Hutton (University of Venda) and Glenrosa (Ha-Davhana village). The samples were scanned using Nikon XTH 225L micro-focus CT X-ray unit. The scans were reconstructed into three-dimensional volume data set of pore shapes, pore size and porosity among the soils using CT Pro software® and further analysed using VG Studio Max V3.0®. images were acquired after 30 minutes in each scan. The result of the study indicated that total porosity decreases with increase in depth, and the shape of the aggregates were dominated by regular pores that are susceptible to water erosion. Moreover, soil pores inform of mesopores, micropores, and macro pores were recorded using 3D images acquired .By visualizing hydro physical properties using images in 2D and 3D, it was possible to visualize arrangement of aggregates and their sizes helping to understand the erodibility of soil. In conclusion X-ray computed tomography is an effective tool to study the microstructure of soil aggregates.
Open Access
Assessment of the effect of fungicides on powdery mildew development on butternut squash
(2016-03-10) Mafa, Maite Sarah; Kunjecu, E. C.; Samie, A.
Open Access
Biochar and Poultry Litter Effects on Maize Growth, Nutrient Uptake and Selected Soil Biological Activities in Different Soil Types
(2022-07-15) Ntsoane, R. L.; Odhiambo, J. J. O.; Kutu, F. R.; Kutu, F. R.
South African soils contain lesser percent organic carbon content compared to soils from many parts of the world. The loss in organic carbon content reduces soil fertility and drives an ever increasing demand for the use of soil amendments to enhance soil fertility. The study consiststed of a greenhouse pot experiment and a laboratory incubation experiment. The objective of a greenhouse study was to assess the effects of biochar and poultry litter application on maiize productivity under different soil types. Treatments consisted of different soil types and amendments of biochar and poultry litter. Soils were collected from four sites (Mutshenzheni, Rambuda, Tshiombo Irrigation and Tshiombo Madzivhandila) representing different soil types (Westleigh (We1), Hutton (Hu), Westleigh(We2) and Shortlands (Sd), respectively. Soils were amended with biochar and poultry litter. The amendments consisted of various mix ratios of biochar (BC) with poultry litter (PL) as treatments, which are namely, BC0PL0, BC100PL0, BC75PL25, BC50PL50, BC25PL75, and BC0PL100. Soil amendments were applied at different rates of 0- 5 t ha-1 PL and 0- 40 t ha-1 BC. Treatments were laid out in a completely randomize design (CRD) and replicated three times. Biochar and poultry litter application exerted no significant difference on soil pH of We2, Sd, and Hu soils. However, the effect of biochar and poultry litter application was significant at soil We1. In contrast, application of biochar and poultry litter had no effect on soil total N of soil We1, We2, and Hu and was significant on soil Sd. The results of this study showed that application of biochar and poultry litter treatments had no significant effect on both the maize growth and nutient uptake at early stages ( Week 1 and Week 2). However, the application of biochar and poultry litter treatments had a significant difference ( p ≥ 0.001) on maize growth and nutrient uptake at a later stage ( Week 3 to Week 6). Therefore, there is a potential to ameliorate fertility constraints in agricultural soils using biochar combined with poultry litter. Though biochar possesses some essential elements required for plant growth, sole application reduces its efficiency with its effectiveness confirmed only when applied in combination with organic-based materials such as poultry litter. The laboratory incubation experiment assessed the effects of different biochar rates on soil chemical and bio-quality parameters. Each treatment consisted of a 200 g of soil (We1, Hu, We2 and Sd) homogenously mixed with biochar amendments (0, 10, 20, and 40, t ha-1). The treatments were laid in a completely randomize design (CRD) and replicated three times. Soil sampling was done on day 0, 30, 60, 90, and 120, and samples were analyzed for soil available P and N and bio-quality parameters namely microbial biomass nitrogen, microbial biomass carbon, urease, alkaline and acid phosphatase, β glucosidase, soil organic carbon, and dehydrogenase activity. The results of the study revealed various responses of soil bio-quality parameters and selected soil chemical properties after biochar and poultry litter application. Thus, the effects of biochar rate, incubation days and soil type on soil enzymes and other bio-quality parameters elicited an understanding on microbial activity and soil enzymes mechanism . Therefore, a prolonged study (more than 120 day) is required to evaluate the effects of incubation days, biochar rate and soil type effect on soil nutrients and bio-quality parameters.
Open Access
Biochar and poultry manure effects on selected soil physical and chemical properties and maize (Zea Mays) in a dry environment
(2018-05-18) Musumuvhi, Thabelo; Odhiambo, J. J. O.; Mzezewa, J.
Poultry manure (PM) is an inexpensive source of fertilizer but it decomposes quickly and releases carbon and greenhouse gases. Biochar (BC) could be an alternative source of carbon to improve soil quality and reduce greenhouse gas emission. This study investigated the effect of co-application of BC and PM on selected soil physical and chemical properties and performance of maize. A field experiment was conducted at the University of Venda experimental farm during 2015/2016 and 2016/2017 seasons. The experiment was a 4 x 3 factorial arrangement consisting of four rates of BC (0, 5, 10 and 20 t ha-1) and three rates of PM (0, 2, and 4 t ha-1) in a RCBD arrangement replicated three times. Maize was planted in both seasons. After harvest, soil bulk density was determined at four soil depths (0-5, 5-10, 10-15, and 15-20 cm), while aggregate stability and selected soil chemical properties were determined at two soil depths (0-15 cm and 15-30 cm). Data were subjected to ANOVA using Genstat 17th edition. The least significant difference was used to compare the treatment means at P < 0.05. Soil aggregate stability, organic carbon, Ca2+, Mg2+, K+, maize dry matter and maize grain yield increased with increasing rates of BC and PM application at 0 - 15 cm depth in both seasons. The combination of BC at 20 t ha-1 and PM at 4 t ha-1 significantly (P < 0.05) decreased soil bulk density at 5 - 10 cm depth but increased soil available P and total N at the two depths in both seasons. The results of this study suggested that BC and PM improved soil ability to retain and supply nutrients through improved soil aggregate stability and reduced bulk density thereby improving maize dry matter and grain yield. Combining BC with PM proved to enhance the ability of soil to function by improving selected soil physical and chemical properties thereby improving maize dry matter and grain yield.
Embargo
Characterization and potential for the genetic improvement of pigeonpea (cajanus cajan ) landraces
(2025-09-05) Mashifane, Dipoo Charity; Gwata, E. T.; Shonhai, A.; Mathew, I.
Pigeonpea (Cajanus cajan) is an important grain legume that provides highly nutritious food for human consumption, livestock feeds and fixes considerable amounts of atmospheric nitrogen, thus improving soil fertility. Local farmers utilize traditional unimproved cultivars that are inherently low yielding limiting the adoption of the crop. The narrow genetic base of pigeonpea limits plant breeding efforts aimed at improving the species. Determining the genotypic variation in agronomic and nutritional attributes among pigeonpea genotypes is essential for improving crop productivity and nutritional content of the crop. Nonetheless, there is a dearth of information regarding the characterization and the genetic diversity in agronomic and nutritive attributes in the pigeonpea germplasm pool maintained at the University of Venda. Therefore, the aim of this study was to characterize and evaluate the potential for the genetic improvement of the agronomic and nutritive attributes of pigeonpea landraces. The specific objectives of the study were to: (i) determine the genetic diversity in agro-morphological attributes (ii) determine the genetic diversity in selected nutritive attributes among pigeonpea landraces (iii) characterize the seed storage proteins in pigeonpea landraces and (iv) determine the general and specific combining abilities for agronomic attributes among pigeonpea landraces. For the first objective of the study, the genetic variation for agronomic and morphological traits among fourteen pigeonpea landraces from the germplasm pool maintained at the University of Venda was evaluated. The genotypes were raised in pots filled with top (up to 25.0 cm deep) soil from the field in the shadehouse for two consecutive seasons. In each season, the experiment was laid out in a completely randomized design replicated three times. Qualitative traits such as the branching pattern, stem colour, flower colour, pod colour and testa colour were recorded. The quantitative traits that were recorded included plant height at flowering (PHF), number of primary branches (NPB), number of secondary branches (NSB), number of seeds per pod (NSP), number of pods per plant (NPP), pod length (PL), hundred seed weight (100-SW) and grain yield per plant (GYPP). The Shannon Weaver diversity index (H’) revealed that the testa colour (1.254) and seed colour pattern (1.301) were the most divergent qualitative traits. There were marked differences in the duration to flowering ranging from 84.67 to 132.83 days with a mean of 117.05 days. The genotype ‘T1’ required <90 days to flower. The local genotype ‘L3’ was among the large seeded (>16.0 g per 100 seeds). The grain yield per plant varied between 19.9 – 51.7 g. The best performing genotypes (with mean GYPP > 45.0 g) were ‘L1’ and ‘L5’. The principal component analysis (PCA) revealed that the first two principal components with eigenvalues of more than one accounted for 58.04% of the variation among the pigeonpea genotypes. Positive correlations observed between most secondary traits showed that multiple trait selection is possible. The NPP, 100-SW and GYPP were the most important agronomic attributes for assessing genetic variation due to their high contribution to the variation accounted on PC1 and PC2. The findings revealed the potential for exploiting genetic diversity to improve pigeonpea agronomic performance. The second study objective focussed on determining the diversity in nutritional attributes among pigeonpea landraces. Seed samples (5.0 g each) from each of the genotypes harvested from the study of the first objective were harvested and processed for determining mineral composition using the Inductively Coupled Plasma Emission Spectrometer. Relatively high amounts of calcium (2103.43 mg/kg) and manganese (73.11 mg/kg) were observed in ‘L3’. High amounts of zinc (38.56 mg/kg) were observed for ‘L9’ whereas ‘L4’ produced high levels of phosphorus (4945.12 mg/kg). The PCA showed that the first two principal components cumulatively explained 62.06% of the total variation among the pigeonpea genotypes. On the PCA biplot, Ca, Mg, Mn and P were associated with ‘L3’, ‘L4’ and ‘L5’ respectively. Genotypes producing high crude protein and high mineral concentrations in most nutritional traits (i.e., ‘L1’, ‘L3’, ‘T1’ and ‘T4) could be used as parental lines for the genetic improvement of nutritional attributes in pigeonpea. The variability in the range of mineral elements among pigeonpea genotypes indicated that there was genetic potential for selection of parental lines for nutritional quality improvement of the crop. The third study objective was designed to characterize the seed storage proteins of pigeonpea using initially the sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS PAGE) in a 12.0% separating gel in a discontinuous buffer system. The SDS PAGE resolved the pigeonpea seed storage proteins into 21 protein bands with molecular weights ranging from 10 to 250 kDa. The absence of the 42, 58, 130 and 250 kDa subunits in genotype ‘L2’ and the presence of the 58 kDa in genotype ‘T5’ could be used for genotypic identification. Thereafter, gel fractions were excised and prepared for the Liquid Chromatography – Mass Spectrometry analysis (LCMS) to evaluate the proteomic variation in seed and determine their functional spectrum. The spectroscopic analysis identified 446 proteins from pigeonpea seed constituted mainly by stress related proteins such as heat shock protein, proteases and chaperones amongst others. Proteases were localized in the nucleus, cytoplasm, proteasome regulatory particle and complex. The amino acid sequence alignment revealed functional motifs such as the Walker A, Walker B and the DEVD. The MPN (Mpr1, Pad1 N-terminal), PCI (Proteasome, COP9, Initiation factor 3) and AAA+ ATPase were the protein superfamilies recognized from the proteases. There was 97.31% similarity between the 26S proteasome regulatory subunit 4 homolog A (A0A1S2XSJ5) and the 26S proteasome regulatory subunit 4 homolog A-like (A0A1S2XWG8) when the amino acid residues were aligned with each other. The proteomic analysis identified large number of stress related proteins probably due to pigeonpea’s ability to withstand harsh environmental conditions such as drought, salinity and extreme temperatures. The final study objective estimated the general and specific combining ability effects as well as the gene action controlling agronomic traits in pigeonpea at the vegetative stage. Nine progenies derived from three lines and three testers in a line x tester mating design were evaluated for agronomic traits at the vegetative growth stage together with their parents in the shadehouse. Crosses were carried out manually by emasculation using forceps prior to flower opening. Each cross was labelled for subsequent identification. The six parents and their nine F1 progenies were raised simultaneously in the shadehouse in pots (as described above). Agronomic traits such as the PH, NPB, and the branching angle (BA) were recorded. The experiment was laid as a completely randomized design with three replications. Line ‘L3’ was the best general combiner for the NPB and BA exhibiting desirable positive GCA effects of 4.00 and 5.37 in the desirable direction. The tester ‘T4’ had positive and significant GCA effects of 11.815 for PH. The crosses ‘L3xT5’, ‘L4xT2’, ‘L5xT4’ and ‘L5xT5’ were good specific combiners for PH with significant and positive SCA estimates of 13.730, 48.396, 25.352 and 15.185, respectively. The best specific combiners for NPB were ‘L4xT2’ (4.778) and ‘L5xT5’ (5.556). For canopy width, the cross ‘L4xT2’ produced a SCA value of 16.363 followed by ‘L5xT5’ with 15.196 in a desirable direction. The narrow sense heritability for all the traits was low (<12.0%) indicating that there is a predominant role of non-additive gene actions for the traits evaluated in this study
Open Access
Chickpea nitrogen fixation, rhizosphere nutrient concentration and contribution of residual nitrogen to improve maize production in response to biochar application in three different soil types
(2022-07-15) Lusiba, Siphiwe Gloria; Odhiambo, J. J O.; Adeleke, R.; Maseko, S. T.
Soil degradation is a major challenge affecting agricultural production around the world in the twenty-first century. Alternative approaches including the use of biochar and the introduction of legumes that will fix nitrogen though the process of biological nitrogen fixation (BNF) are essential for improving soil quality of current low productive soils, thus increasing crop yields, and maintaining food security while conserving the environment. To address this problem, three experiments were conducted in this study. First, two locally produced biochar from poultry litter and acacia feedstocks were assessed whether they qualify as ‘biochar’ for use as soil amendment according to the international biochar bodies. Secondly, a pot experiment was then conducted to investigate the potential impact of poultry litter biochar (PLB) and acacia biochar (ACB) to improve rhizospheric soil nutrient availability, bacteria abundance and diversity, chickpea growth and total nitrogen fixation in three contrasting soil types. Thirdly, another pot experiment was conducted to determine the contribution of residual N from biochar and N-fixed by chickpea to the following maize crop grown in three contrasting soil type. The treatments consisted of three soil types classified as Fernwood [Arenosol]; Pinedene [Gleyic Acrisol]; Griffin [Helvic Acrisol], sampled from three different smallholder farmers at Dopeni village, Limpopo Province. The two biochars [PLB and ACB] were applied at four application rates of [0% (control), 0.5, 1 and 2% w/w]. The treatments were arranged in a completely randomized design and replicated four times. For the first experiment, chickpea (Cicer arietinum) desi cultivar was inoculated and grown for 65 days in soils with uniformly applied P at 60 kg P/kg in all pots and water maintained at 60% field capacity. For the second experiment, maize (Zea mays) was grown for 95 days in the same soil as chickpea and biochar treatments as well as after harvesting maize that was used as a reference crop. Biochars made from poultry litter and acacia feedstocks meet the International Biochar Initiative (IBI) and European Biochar Certificate (EBC) requirements and qualifies as biochar for use as a soil amendment. Both biochars had C content greater than 50%, with H/C and O/C ratios less than 0.6 and 0.4, respectively, indicating that both biochars are stable for C sequestration and can remain in the soil for about 1000 years. Because poultry litter biochar (PLB) contained more nutrients than acacia biochar (ACB), PLB improved rhizospheric pH, CEC, and nutrient concentration (N, P, K, and Ca) when applied at 0.5-2% in the Griffin and Pinedene soils, resulting in higher biomass production and nutrient uptake of chickpea. In addition, when 2% PLB was applied to those two soils, bacteria capable of fixing N, especially those from the phylum Proteobacteria, were more abundant. Thus, chickpea grown in these soils and at these PLB rates derived more N from the atmosphere, fixed more N, and xvi accumulated more N and C in the shoot, but was less water use efficient. Furthermore, maize grown in 1% residual PLB treatments produced more biomass and accumulated more N and other nutrients than maize grown with 0.5-2% residual ACB treatments. However, when grown after chickpea harvest in residual PLB treatments of 2% in the Griffin and Pinedene soils, maize produced greater biomass and accumulated more N and other nutrients. Application of PLB and ACB at 0.5% in the Fernwood soil was ideal to improve rhizospheric nutrient availability, the abundance of bacteria communities [from the phylum Proteobacteria, Acidobacteria, and Firmicutes which are important for C and N cycling and bioremediation], as well as growth, BNF, and C accumulation of chickpea, including maize growth and nutrient uptake in monocropping or in rotation with chickpea. The greatest variation in relative abundance of bacteria communities and growth of chickpea was due to the substantial change in soil pH and rhizospheric nutrient availability such as N, P, K, and Mg, while biomass production and N accumulation were largely attributed to the improved BNF and C accumulation of chickpea in the clay textured soils. The increased growth and nutrient uptake of the following maize crop in the Griffin and Pinedene soils was attributed to high N inputs through BNF and biochar mineralisation, whereas the variation in bacteria communities, chickpea and maize performance in the Fernwood soil was due to the change in rhizospheric soil pH, P, and K. The findings of this study conclude that biochar made from poultry litter is recommended for use as a soil amendment to improve nutrients and soil quality, although caution should be taken when applied at higher rates (40 t/ha) as it may immobilize N or result in high release of toxic elements. Furthermore, incorporating chickpea into existing maize cropping systems of smallholder farmers and using biochar made from poultry litter will help reduce nitrogen input costs by adding residual nitrogen from biochar mineralisation and through BNF, improving soil quality and maize production. On the other hand, biochar made from acacia feedstock will be excellent for use to improve soil organic carbon and water adsorption, but it should be applied months before planting or supplemented with high organic N and P materials when used as a soil amendment to improve nutrient availability, as it may temporary fix N and P in the soil. When using poultry litter or acacia biochar on a poorly buffered loamy sand soil like the Fernwood, care should be taken to avoid over liming, which can cause nutrient deficiency and negatively affect nutrient uptake. Moreover, to improve chickpea and maize performance in sandy textured, highly leached soils like the Fernwood, biochar should be applied regularly or combined with organic materials to improve soil organic carbon to allow the soil to retain and release nutrients for plant uptake.
Open Access
Combining Ability for Ear Prolificacy and Response of Prolific Maize (Zea May L.) Hybrids to Low Nitrogen Stress
(2018-09-21) Makhumbila, Penny; Gwata, E. T.; Mashingaidze, K.
Smallholder farmers in Sub-Saharan Africa still obtain low grain yields in maize largely due to low soil fertility. The soils are inherently low in nitrogen (N) that is required for the proper development of the maize plant. Currently there are no commercial cultivars for low N tolerance locally. The combining ability approach can be used as a tool for breeding desirable cultivars. In order to improve grain yield in maize, it is important to consider ear prolificacy which is a major yield component. Therefore this study was designed to estimate combining ability in maize. Exotic germplasm from the International Maize and Wheat Improvement Center and the Institute of Tropical Agriculture as well as the local germplasm from the Agricultural Research Council was used in the study to generate crosses. One hundred and two crosses were evaluated together with a standard commercial check under low N and optimum N conditions. The specific objectives of the study were to determine general and specific combining ability for prolificacy among local and exotic inbred lines and evaluate the response of prolific hybrids to low N conditions. The hybrids were planted in the 2014/2015 summer season under irrigation in Potchefstroom, Cedara and Taung in field plots consisting of 0.75m x 0.25m spacing in a 0.1 alpha lattice design replicated twice. Data for agronomic attributes were recorded and subjected to analysis of variance using SAS version 9.1.3. Genetic correlations were analyzed using the Principal Components Analysis and factor analysis based on the correlation analysis and major traits. The results showed variation in agronomic performance among the inbred lines and their F1 hybrids. Inbred lines including TZEI63, T1162W, L15 and L17 showed positive GCA estimates for ear prolificacy at the different locations. Specific combining ability for prolific hybrids was positive at all locations and environments. The GCA:SCA ratio was close to unity; indicating that the number of ears per plant showed highly significant (P<0.01) correlation with grain yield. The hybrids showed ear prolificacy under the low N conditions. This trait can be used effectively in stress tolerance maize breeding programmes.
Open Access
Conservation agriculture and slope position effect on selected soil physical properties of a Vertisol at Tshivhilwi in Limpopo Province
(2023-10-05) Tshilonga, Mushe Moses; Mzezewa, J.; Odhiambo, J. J. O.
Conservation agriculture (CA) is a production system that involves three principles which are minimal or zero tillage, crop rotation and mulching with plant residues. CA improves soil physical properties resulting in soil fertility improvement. However, there are relatively few studies that have documented the benefits of CA on soil physical properties of vertisols. A study was conducted to determine the influence of CA and slope position on soil bulk density (BD), total soil porosity (Vf), soil aggregate stability (AS), soil water holding capacity (WHC), soil organic carbon (SOC), soil electrical conductivity (EC), infiltration rate (IR) and cumulative infiltration (CI) of a vertisol, at Mutanga Wa Ndodzi Agricultural Co-operative at Tshivhilwi village where CA has been in practice since 2013. The farm practices CA with crop rotation. The field used for CA was tilled once in 2013 using a mouldboard plough. Mulching is done using maize stalks. After planting fertilizer was applied based on crop requirement. One set of soil samples were collected from a field under CA while another set was collected from a field under natural grass (control) which is located directly opposite the CA field. Soil samples were collected 10 m apart from 0-10 and 10-20 cm depths along the transects which were at, 10 m apart. A core of diameter of 5 cm and height of 5 cm was collected to determine soil BD. SOC was determined using the modified Walkley-Black wet oxidation procedure. EC was measured with glass electrode professional EC meter in 1:5 ratio soil water suspension. Soil AS was determined using wet sieving method. Soil particle density was determined using a pycnometer bottle after which the bulk density and particle density of the soil were used to calculate soil porosity. Soil WHC was determined by saturating with water 25 g of oven-dried soil in a glass funnel and its water holding capacity determined by gravimetric method. Management and slope position interaction had a significant effect at 0-10 cm and 10-20 cm soil depth with lower BD at the CA site lower slope position at 0-10 cm soil depth. SOC was significantly higher on lower and middle slope of CA than natural grassland (NG) site. The CA site x recorded higher EC at the middle and lower slope positions compared to NG site. Higher AS was observed at the CA site than NG at all slope position at 0-10 cm soil depth, at 10-20 cm CA site recorded higher AS at the lower and middle slope. Vf was significantly higher at the CA site than NG site at all slope positions, CA lower slope was associated with higher Vf followed by middle and summit slope. CA site exhibited a higher WHC than NG site at all slope positions, CA middle lower slope positions had the highest WHC. Interaction effect was observed on final IR however, the significant difference between the two-management system was observed at lower and middle slope. Conservation agriculture and slope position interaction in this research resulted in significantly higher BD, SOC, EC, AS, vf and WHC but had no effect on BD middle slope and summit slope positions at 0-10 cm, SOC summit and lower slope positions at 10-20 cm soil depth, EC summit slope at 0-10 cm, vf at summit and middle slope at 10-20 cm soil depth and WHC lower slope lower slope position at 10-20 cm soil depth. According to the findings of this study, practicing conservation agriculture in various slope positions could be recommended to improve soil properties (bulk density, soil organic carbon, soil electrical conductivity, aggregate stability, total soil porosity, water holding capacity and infiltration rate) of a Vertisol.
Open Access
Distribution of retroacizzia Mopani and its natural enemies in Tshikundamalema Area, Limpopo Province, South Africa
(2017-09-18) Mmbengeni, Rofhiwa Isaac; Kunjeku, E. C.; Hurley, B. P.
Colophospermum mopane (Fabaceae), commonly known as mopane tree, is an indigenous tree species in Southern Africa, often being the dominant species in semi-arid areas. It plays an integral part in the improvement of communities’ livelihoods when it is harvested for firewood and mopane worms which are edible insects are collected from the tree. Colophospermum mopane is host to many insects, among them Retroacizzia mopani, a leaf pest. Retroacizzia mopani produces lerps which are protective exudates that shield the insect from predation, but lerps also reduce the photosynthetic area of mopane leaves. This study aimed to determine the distribution of the African mopane psyllid, R. mopani and its natural enemies in the Tshikundamalema area, in Limpopo Province. The study assessed the presence of lerps on C. mopane, as well as determining the effect of site, tree height, tree density, tree position, branch size and neighbouring trees on R. mopani infestations at three sites. Sample of leaves infested with R. mopani were collected at six different sites and reared in the laboratory to determine the prevalence of R. mopani natural enemies and the levels of parasitism. The site, tree density, tree position, and branch size had an effect on the R. mopani infestations. The results showed that as the tree density, tree height and branch size increased, R. mopani infestation also increased. Neighbouring trees had no effect on R. mopani infestations. Trees found at the edge of the forest were more heavily infested compared to those that were inside the forest. All the three sites had low levels of parasitism by the natural enemy, Psyllaephagus arytainae Prinsloo. This indicates that P. arytainae has little effect on population dynamics of the psyllids.
Embargo
Diversity and species overlap of Botryosphaeriaceae on some trees of Anacardiaceae in disturbed and undisturbed ecosystems in South Africa
(2025-05-16) Ramabulana, Elelwani; Ogola, J. B. O.; Kunjeku, E.; Coetzee, M. P. A.; Slippers, B.
The Botryosphaeriaceae are common and diverse on native and non-native plants. It has been established that the ability of Botryosphaeriaceae fungi to exist in healthy plant tissues as endophytes facilitates their global movement during the international trade of plants and plant products. It is important to understand whether fungi in the Botryosphaeriaceae have a restricted host range or a limited geographic distribution once introduced into new areas, and how ecosystem disturbances through human activities influence species diversity and distribution of fungi in the Botryosphaeriaceae. The current study explored Botryosphaeriaceae species diversity on native and non-native tree species of Anacardiaceae found in disturbed and undisturbed ecosystems, as well as species overlap of the Botryosphaeriaceae as endophytes and as pathogens in asymptomatic and symptomatic tissues of these trees. In addition, the genetic diversity and population structure of N. parvum, the dominant species occurring on asymptomatic mango fruit were assessed. These questions were addressed by sampling three tree species of Anacardiaceae, namely Sclerocarya birrea (marula), Mangifera indica (mango) and Lannea Schweinfurthii (false marula) in disturbed and undisturbed ecosystems in the Limpopo and Mpumalanga provinces, South Africa. The ecosystem disturbance study identified 11 species of Botryosphaeriaceae, namely Diplodia allocellula, Dothiorella brevicollis, Dothiorella dulcispinae, Dothiorella viticola, Lasiodiplodia crassispora, Lasiodiplodia exigua, Lasiodiplodia gonubiensis, Lasiodiplodia mahajangana, Neofusicoccum parvum, Oblongocollomyces ednahkunjekuae and Oblongocollomyces sp. 1 occurring on native and non-native Anacardiaceae in disturbed and undisturbed ecosystems. Ten of the 11 species were identified on trees in undisturbed ecosystems, while three were identified on trees in disturbed ecosystems. Lasiodiplodia crassispora and L. mahajangana were generalists on trees in disturbed and undisturbed ecosystems. The results from this study also indicated the ability of some species to cross-infect native and non-native Anacardiaceae growing next to each other. For example, N. parvum isolates occurred on both S. birrea (a native species) and M. indica (a non-native species) trees adjacent to each other in disturbed ecosystems. An investigation on species occurrence of the Botryosphaeriaceae as endophytes and as pathogens on the Anacardiaceae identified 12 species of Botryosphaeriaceae, D. allocellula, Dothiorella brevicollis, Do. dulcispinae, Do. viticola, Lasiodiplodia crassispora, L. exigua, L. gonubiensis, L. mahajangana, L. pseudotheobromae, Neofusicoccum parvum, Oblongocollomyces ednahkunjekuae and Oblongocollomyces sp. 1 in asymptomatic and symptomatic tissues. Dothiorella dulcispinae, L. exigua, L. gonubiensis, Oblongocollomyces ednahkunjekuae and Oblongocollomyces sp. 1 were exclusive to asymptomatic Anacardiaceae, while D. allocellula, Do. brevicollis, Do. viticola, L. crassispora, L. mahajangana and N. parvum occurred in asymptomatic and symptomatic Anacardiaceae indicating the ability to occupy healthy plant tissues as latent opportunistic pathogens on these trees. The N. parvum population genetics data was assessed based on nine microsatellite markers. This study indicated that the N. parvum population consists of three distinct genetic clusters characterized by high levels of genetic diversity. The three clusters were not correlated to host or geographic location indicating the lack of barrier on the movement of the fungus between the hosts and locations sampled. The study highlights the potential of mango fruit to serve as a source of international spread of Botryosphaeriaceae, especially of N. parvum.
Open Access
Diversity of fungi associated with dieback of Ziziphus Mucronata in Limpopo Province, South Africa
(2020) Thaphathi, Polly; Kunjeku, E. C.; Ogola, J. B. O.; Coetzee, M. P. A.
Ziziphus mucronata (buffalo thorn, Rhamnaceae) is an indigenous tree that serves multipurposes to rural communities and wildlife across Africa. The tree is considered important because of its useful parts for various purposes. For example, leaves of this tree can be consumed as a vegetable by humans and wild animals such as antelopes and baboons feed on them. Fruits from Z. mucronata are edible and nutritious to both human and wild animals such as monkeys. Roots from this tree are used for medicinal purposes by people living in rural areas for treatment of wounds, snake bites, swelling glands as well as diarrhoea. However, the tree face diseases such as dieback that negatively affect its production and there is little research on diseases of Z. mucronata in South Africa. This study was conducted in Limpopo Province, in three different sites namely Tshikundamalema, Buzzard Mountain Farm and Wits Rural Facility to identify fungi from branches of Z. mucronata showing dieback symptoms. Symptomatic branches were collected from each site and processed in the laboratory before primary isolations. Isolates obtained from the samples collected were identified based on their morphology where isolates were grouped according to their morphological characteristics such as colour and structure of mycelia. The isolates were further identified based on DNA sequence data from multiple genome regions including the internal transcribed spacer (ITS), beta-tubulin (BT) and the translation elongation factor (TEF) genomic regions and phylogenetic analyses. Fungi identified in this study were from families Botryosphaeriaceae, Diaporthaceae, Cytosporaceae (=Valsaceae), Nectriaceae, Pleosporaceae and Didymellaceae. Fungi identified include Dothiorella (=Spencermartinsia), Diplodia, Botryosphaeria, Neofusicoccum, Fusarium, Diaporthe (=Phomopsis), Cytospora, Didymella (=Phoma) and Alternaria. Results obtained from this study showed the diversity of fungi associated with dieback of Z. mucronata in Limpopo Province. Studies in other parts of Limpopo Province are needed to further investigate the diversity of fungi found on branches of Z. mucronata with dieback.
Open Access
Effect of biochar and phosphorus fertilizer application on selected soil properties and agronomic performance of chickpea (Cicer arietium)
(2015-05) Lusibisa, Siphiwe Gloria; Odhiambo, J. J. O.; Ogola, J. B. O.
See the attached abstract below
Open Access
Effect of biochar and rhizobium innoculation on nodulation, chlorophyll content, growth and yield of chickpea (Cicer arietinum L.)
(2018-05-18) Macil, Patricia J.; Ogola, J. B. O.; Odhiambo, J. J. O.
Soil infertility, water scarcity, and availability of high yielding and drought tolerant crop genotypes remain major constraints for agricultural production in semi-arid regions. These constraints are major threats to sustainable crop production and food security. Management practices in such areas should always be geared towards improving productivity at a low cost while sustaining soil fertility. Preliminary studies showed the huge potential of chickpea in the dry environments of the North Eastern South Africa. However, lack of nodulation in chickpea has been reported in these regions probably due to low soil pH, insufficient rhizobial populations or total lack of infective native rhizobia. Therefore this study assessed the effect of biochar and rhizobium inoculation on soil pH, nodulation, growth, yield and chlorophyll content of chickpea in Mpumalanga (Nelspruit) and Limpopo (Thohoyandou) Provinces, South Africa. Two field experiments were planted during winter 2015 and 2016. Treatments consisted of three levels of biochar (0, 10 and 20 t ha-1), two Rhizobium inoculation levels (with and without Rhizobium inoculation) and three chickpea genotypes (ACC #4, ACC #5, and ACC #6) in a factorial combination arranged in randomized complete block design replicated three times. Crop phenology (days to 50% emergence, flowering, podding, and physiological maturity), crop growth (plant height, canopy cover, number of primary and secondary branches), nodulation (number of nodules per plant and nodule dry weight), yield and yield components (number of pods per plant, number of seeds per pod and 100 seed weight [100-SW]), and chlorophyll content were determined at various crop growth stages. Identification and isolation of native rhizobia from soils was done using standard protocols. Data obtained were subjected to analyses of variance using the general linear model of Genstat software version 17. Significant differences between the treatments means were compared using the standard error of difference (SED) of the means at 5% level. Correlation analyses were performed to assess the relationship between parameters. Molecular data was subjected to BLASTn in National Centre for Biotechnology Information (NCBI) searches for identification of isolated strains Application of biochar at 10 and 20 t ha-1 increased soil pH by 0.7 pH units in Thohoyandou (clay soil) in 2015 and 2016, respectively. Soil pH increased by 0.77 pH units at 10 t ha-1 and 1.2 pH units at 20 t ha-1 in Nelspruit (loamy sand) in 2015 and 2016, respectively. Similarly, rhizobium inoculation increased soil pH by 0.2 (Thohoyandou) and 0.5 (Nelspruit) pH units in 2015 and 2016, respectively. There was a 100% increase in nodulation in inoculated compared to uninoculated treatments. There was no effect of biochar and rhizobium inoculation on number of days to 50% flowering, podding, v physiological maturity and on plant height. However, plant height varied with genotypes. Biochar application increased above ground biomass by 17% (10 t ha-1) and 12% (20 t ha-1), and 100 seed weight by 9% (10 t ha-1) and 7% (20 t ha-1) in Thohoyandou in 2015. Rhizobium inoculation increased yield and yield components in Thohoyandou in both seasons; biomass was greater by (31 and 23%), grain yield (26 and 24%), number of pods per plant (18 and 31%), and 100-SW (10 and 13%) in 2015 and 2016, respectively. Similarly, rhizobium inoculation increased biomass (53.4%), grain yield (81%), number of pods per plant (54%) and number of seeds per pod (89%) in Nelspruit in 2015. Genotype did not affect yield and yield components in Nelspruit. In contrast, genotype affected above ground biomass, grain yield, harvest index, number of pods per plant, and number of seeds per pod in 2015 in Thohoyandou with ACC #6 producing greater yield compared to ACC #4 and 5. The analysis for native rhizobia showed that agricultural fields in Nelspruit and Thohoyandou lack effective strains of rhizobium. The identified strains according to 16s gene region were Klebsiella variicola, Burkholderia cenocepacia, Bacillus subtilis and Ochrobactrum spp. The effects of biochar and rhizobium inoculation were more pronounced in Thohoyandou compared to Nelspruit. Therefore biochar and rhizobium inoculation may improve chickpea productivity in Limpopo and Mpumalanga Provinces through improved soil pH, nodulation, growth, yield and yield components.
Open Access
Effect of biochar derived from different feedstocks on nitrogen retention availability, and uptake by a maize crop
(2024-09-06) Khethani, Thakhani; Odhiambo, J. J. O.; Lusiba, S. G.
Nitrogen (N) is an essential nutrient for most crops and can be provided directly by fertilisation or indirectly through atmospheric deposition, fixation, all of which can then be converted to nitrate through mineralization and nitrification. Incomplete N utilisation by crops leaves residual soil nitrate, which is water soluble and susceptible to leaching into groundwater, particularly in regions dominated by light-textured sandy soils with low WHC. Application of biochar (BC) can potentially have a significant impact on nitrogen retention and availability. BC is a charcoal-like substance that’s made by burning organic material from agricultural and forestry wastes (also called biomass) in a controlled process called pyrolysis. Biochar can increase organic matter content, act as a liming agent, add basic cations and micronutrients, improve water holding capacity, and release nutrients gradually to the growing plant. This study evaluated the effect of BC derived from different feedstock on nitrogen retention and availability. Two experiments’, laboratory (column leachate) and nursery experiments were conducted at the University of Venda Soil Science Laboratory and the School of Agriculture Experimental Farm, respectively. The treatments in both experiments 1 and 2 consisted of a factorial combination of BC from three different feedstocks (acacia, hay, and poultry litter) and three BC application rates (0%, 1%, and 2%). In experiment 1, the levels of NH4+ and NO3- leached from and retained in the soil were determined in the laboratory experiment before and after 70-day leaching period. The columns were first filled with three kilograms of the soil-BC mixture based on the previously mentioned treatments, giving rise to an initial bulk density of roughly 1.5 g/cm3. A single fertiliser application with 100 mg of solutioned ammonium nitrate (NH4NO3) was applied to each column. The fertilizer was applied to each column's surface in uniform drips after being diluted in 5 millilitres of distilled water. In the laboratory, the columns were maintained at room temperature, or roughly 23 °C. Every two weeks, 200 ml of distilled water was added to each column through a funnel that was placed above the center of each column. To aid in the dispersal of the water drips, filter papers were placed on the soil surface of the columns. Columns were allowed to drain freely during the leaching process, and all leachate samples were collected in foil-wrapped Erlenmeyer flasks to minimize evaporative loss. For 10 weeks (seventy days), columns were leached every two weeks. Every two weeks, the leachates were collected and chilled before analysis to minimize the growth of algae. Leachates were collected every two weeks, and the pH and electrical conductivity (EC) were measured. The leachate samples were then filtered through Whatman No. 42 filter paper to measure the amounts of nitrite (NO3-) and ammonium (NH4+). In experiment 2, which was conducted in a nursery, 5 kg of soil was placed in pots measuring 25 cm in height and 25 cm in diameter. Maize (Zea mays L.) was used as a test crop and harvested 56 days after planting. xviii The measurements made in this experiment were dry matter (kg) and nitrogen uptake (kg/ha). A uniform application of nitrogen fertilizer (LAN) at a rate of 100 kg N/ha was given to each pot. The soils were treated with BC as per the stated application rates and ammonium nitrate fertilizer one week prior to planting. The treatments were arranged in a completely random design (CRD) The pots were wetted to 60% field capacity (FC) and allowed to dry out for 24 hours prior to planting. Three maize seeds were planted in each pot. After watering, the pots were filled to 60% of their field capacity (FC). After being allowed to develop for a maximum of eight weeks (56 days), maize crops were collected, dried, weighed, ground, and the N content determined. In experiment 1, the current study's findings show that using BC can significantly reduce the leaching of highly mobile nutrients like NH4+ and NO3-. The total amount of leachates collected increased by 46% and 42% at the 1% and 2% biochar application rates, respectively. The amount of ammonium and nitrate retained increased by 1.62% and 16.2% at a 2% rate of application, respectively. In comparison to the control, where no BC was added, BC significantly reduced ammonium leaching at 1% on days 56-70 and 2% (w/w) in BC-amended soils. Biochar increased EC in all BT and retained NH4+ and NO3-. In experiment 2, this study has shown that feedstock type significantly affects biomass accumulation and N uptake. Biomass yield and N uptake increased in the order poultry litter > acacia > hay. Increasing biochar rates from 0 to 2% increased biomass accumulation and N uptake. In summary, biochar type and rate of application have a potential effect on N leaching and retention in the soil, as well as the biomass and N uptake and therefore these factors should be considered when biochar is used as a soil amendment, especially for N management in agricultural systems.
Open Access
The effect of biochar on immobilization and phytoavailability of chromium, nickel and lead in soils amended with slag
(2020) Letsoalo, Morakene Lambert; Odhiambo, J. J. O.; Lukhele-Olorungu, P.
Application of industrial wastes in agricultural fields as sources of plant nutrients has become a common practice in agriculture. In other countries and recently South Africa, steel plant slag (SPS) (an industrial waste) is used in agricultural fields as liming material. Steel plant slag is a potential source of plant nutrients, especially in areas where plant iron chlorosis is a problem. The use of SPS as liming material on agricultural soils seems viable despite the detrimental effects due to heavy metals contained in SPS. The presence of heavy metals [chromium (Cr), nickel (Ni) and lead (Pb)] in higher concentrations in potential agricultural soils has negative effects to fauna and flora. Naturally soils possess traits that counter the accumulation of heavy metals, for example, texture and pH of a soil can play a role in the adsorption of heavy metals. An alternative strategy would be that capable of enhancing the metal-binding capacity of soil amendments such as biochar. In this study, the aim was to evaluate the effect the different types of texture, the efficacy of different types of biochar and rate of biochar on the concentration of chromium, nickel and lead. The greenhouse pot experiment was therefore conducted to investigate the effect of biochar on the immobilization and phytoavailability of chromium, nickel and lead in soils amended with slag. A 2 x 2 x 4 factorial experiment was conducted with three factors consisting of two soils (sandy and clay), two biochar and four biochar rates (0 t/ha, 5 t/ha, 10 t/ha, and 20 t/ha). All the soil and biochar were thoroughly mixed. 4 kg of soils was placed in a pot. Slag was then applied to each pot at an amount equivalent to 15 g/kg (75 g per pot). The treatments were replicated four (4) times to give a total of 64 pots and were arranged in a completely randomized design (CRD) in a greenhouse. The soils were analyzed for texture, exchangeable cations (Mg2+, Ca2+, K+), pH, electrical conductivity and soil aggregates. Slag was analyzed for potassium, phosphorus, pH, electrical conductivity, total nitrogen, chromium, nickel and lead, and biochar was analyzed for organic carbon content, pH, electrical conductivity, calcium, magnesium, potassium and phosphorus. The data showed that acacia and poultry litter biochar significantly (P< 0.01) immobilized and reduced the phytoavailability of Cr, Ni and Pd in the soil. For example, the application of 20 t/ha biochar in this study significantly decreased the concentrations of chromium, nickel and lead. The biochars immobilized the selected heavy metals from a range of 9.3% to 89.9% and reduced the phytoavailability from a range of 0.0248% to 8.1x10-8%. Acacia and poultry litter biochar significantly increased the shoot dry biomass of spinach plant by 1.2% to 85.1%. Following the application of biochar to the soil, electrical conductivity and pH increased significantly (P< 0.01) from 24% to 22% and 11.3% to 44.7% respectively. Application of acacia and poultry litter biochar significantly (P <0.01) increased soil stable aggregates by 14.3% to 43.5%. Application of acacia and poultry litter biochar reduced the toxicity of heavy metals (chromium, nickel and lead) in spinach by immobilizing and reducing phytoavailability of the heavy metals. Acacia and poultry litter biochar have positive effects on the soil pH, electrical conductivity, plant growth (shoot dry biomass of spinach) and soil stable aggregates.
Open Access
Effect of biofertilizers on phosphorus nutrition and grain yield of des chickpea (Cicer arietinum L.) grown in different agro-ecologies
(2024-09-06) Mashishi, Sina; Ogola, J. B.O.; Odhiambo, J. J. O.; Maseko, S. T.
South African soils are predominantly acidic and have high levels of Al and Fe, giving a higher P sorption capacity and low P levels. Consequently, soil fertility has become a major constraint in South Africa’s farming, thereby threatening crop production and food security. Literature reveals, however, that biofertilizers have the potential to improve crop growth, grain yields and, acid and alkaline phosphatase activities in both the plant tissue and soil. Nonetheless, there is scant information about the biofertilizers’ effects on their co-application with rhizobium inoculation as most of the studies focused on the sole application of the biofertilizers such as Bontera, Kelpak, Mycorrhiza, and Rhizobium inoculation. This study evaluated the biofertilizers’ effects on the phosphorus accumulation in the rhizosphere soil, the acid and alkaline phosphatase activity in the rhizosphere soil and, the two chickpea genotypes’ growth and yields under different environments. In 2019, three field experiments were conducted in three locations, namely Thohoyandou, Syferkuil, and Sikhwahlane, and two more were done at Thohoyandou and Syferkuil in 2021. The treatments consisted of a factorial combination of six biofertilizer levels (Mycoroot, Kelpak, Rhizobium inoculation, Kelpak+Rhizobium inoculation, Mycoroot+Rhizobium inoculation, zero control) and two chickpea genotypes (Accession 3 and Accession 7). These were arranged in a three-time replicated randomised complete block design. The intercepted radiation’s (IR) proportion was measured using the AccuPAR LP-80 ceptometer at Thohoyandou in 2019 and 2021. The chlorophyll content was measured at vegetative and reproductive stage using a chlorophyll meter (CCM-200 PLUS, Opti-Science) at Thohoyandou and Syferkuil in 2021. The stomatal conductance (gs) was measured using a portable porometer (AP4 DELTA-T Device) at the vegetative and reproductive stage at Thohoyandou in 2021. The normalised different vegetation index (NDVI) was measured using the portable GreenSeeker at the vegetative stage at Thohoyandou and Syferkuil in 2021. The chlorophyll fluorescence was measured at the flowering stage using the portable chlorophyll fluorometer at Thohoyandou, Syferkuil, and Sikhwahlane in 2019; and at Thohoyandou and Syferkuil in 2021. The acid and alkaline phosphatase activities were measured at the flowering stage at Thohoyandou, Syferkuil, and Sikhwahlane in 2019, and at Thohoyandou and Syferkuil in 2021. The inorganic phosphorus was measured at the flowering stage at Thohoyandou and Syferkuil in 2021. The yield and yield components (pod weight, shoot biomass, and harvest index) were measured at the harvest maturity stage at Thohoyandou, Syferkuil, and Sikhwahlane in 2019, and at Thohoyandou and Syferkuil in 2021. Data were analysed for variance (ANOVA) using the STATISTIX (2017) version 10.0. The Tukey’s honestly difference (HSD) test was used to separate the means that were significantly different (P≤0.05). The Pearson correlation was used to test the linear association’s strength between the parameters studied. The biofertilizers significantly increased the intercepted radiation’s proportion (%IR) at Thohoyandou in 2019 and 2021. The Kelpak sole and in combination with the rhizobium inoculation on 61DAE (86.71) and 75DAE (85.10) recorded the highest %IR in 2019 cropping season. The rhizobium inoculation recorded the highest %IR at 47DAE (50.17) & 83DAE (80.67) and the Kelpak+Rhizobium inoculation recorded the highest %IR at 61DAE (54.33) & 75DAE (68.67) in the 2021 cropping season. The genotype had no significant effect on %IR in both seasons but the interaction between M x accession7 gave the greatest proportion of the intercepted radiation in 2019. The chlorophyll content was significantly increased by the biofertilizers at Thohoyandou (clay soil) only in 2021 with the Kelpak combined with rhizobium inoculation recording the greatest chlorophyll content (2.13-3.10) in all measurement dates. However, the genotype affected the chlorophyll content at 74DAE with accession7 recording the highest chlorophyll content compared to accession3. However, the interaction between the biofertilizer and the genotype had no significant effects on the chlorophyll content in all sites. The stomatal conductance was significantly affected by the biofertilizer application with K+R recording the highest gs at 42DAE (529.25) and M+R recording the highest gs at 56DAE (473.08) at Thohoyandou in 2021. Both the genotype and interaction between the biofertilizer and the genotype significantly affected the gs at 70DAE with accession3 recording the highest gs compared to accession7, and the Mycoroot x accession3 recording the highest gs. The normalised difference vegetative index was significantly increased by the biofertilizer application at 28DAE & 42DAE at Syferkuil only (sandy soil) with Mycoroot and K+R recording the highest NDVI at 28DAE (0.56) and rhizobium inoculation and M+R recording the highest NDVI at 42DAE (0.68). Neither the genotype nor the interaction between the biofertilizer and the genotype had a significant effect on the NDVI in all sites. The biofertilizer’s application significantly affected the acid and alkaline phosphatase activities in all sites except at Syferkuil in 2021 where the biofertilizers had no significant effect on the alkaline phosphatase activity. The co-application of K+R gave the highest APase at Syferkuil (sandy soil) and Sikhwahlane (loamy soil) in 2019, while at Thohoyandou (clay soil) the co-application of M+R gave the highest APase. In 2021, the co-application of K+R gave the highest APase at Syferkuil and Thohoyandou. The alkaline phosphatase activity was higher with the application of rhizobium inoculation at Syferkuil and Thohoyandou in 2019, and higher with the co-application of M+R (13.03) in Sikhwahlane in 2019. However, the zero control gave the highest AlkPase activity (74.14) at Syferkuil in 2021. At Thohoyandou (2021), however, the Kelpak’s application recorded the highest AlkPase activity (56.81). Inorganic phosphorus was significantly affected by the biofertilizers in both sites. The co-application of K+R recorded the highest inorganic phosphorus at Syferkuil and the sole Kelpak (15.16mg/kg) gave the highest inorganic phosphorus at Thohoyandou in 2021. The genotype had no significant effect on the APase and AlkPase activities but significantly affected the inorganic phosphorus at Syferkuil with accession3 (55.61mg/kg) recording the highest Pi compared to accession7. The interaction between the biofertilizer and the genotype affected the APase and inorganic at Thohoyandou, and only the Pi at Syferkuil in 2021. Among the various biofertilizers used at Thohoyandou, the rhizobium inoculation recorded the highest quantum yield of PSII (0.24 to 0.33) in 2019. The biofertilizers, however, significantly affected the PSII, Fv/Fo, and Fv/Fm at Syferkuil in 2021 with the rhizobium inoculation exhibiting the highest PSII, Kelpak exhibiting the greatest Fv/Fo, and the sole Mycoroot and Mycoroot combined with the rhizobium inoculation exhibiting the strongest Fv/Fm. Among the biofertilizers administered at Thohoyandou, the Kelpak and rhizobium inoculations gave the highest PSII, and the Kelpak sole gave the greatest Fv/Fo. The genotype significantly affected the minimal fluorescence (Fo) in Sikhwahlane in 2019. It was pronounced in accession7 than in accession3 and the genotype affected the Fv/Fm at Syferkuil and was more pronounced in accession7 than in accession3. In 2019’s cropping season, the biofertilizers increased the pod weight and grain yields at Thohoyandou to above-ground biomass and grain yield at Syferkuil, and pod weight to above-ground biomass and the grain yield in Sikhwahlane. In both sites in 2021, the biofertilizers increased the above-ground biomass, harvest index, and grain yield. Accession7 gave the highest value of pod weight at Syferkuil’s cropping season in 2021. The interaction between the biofertilizer and the genotype had no significant effect on the grain yield and yield components in all the locations and in both cropping seasons. Therefore, this makes the biofertilizers an effective tool for increasing the chickpea’s yield in these regions.
Open Access
The effect of chemomutagenesis on root nodulation and seed protein in tepary bean (Phaseolus acutifolius)
(2018-05-18) Mashifane, Dipoo Charity; Gwata, E. T.; Bessong, Pascal
Tepary bean (Phaseolus acutifolius) is an important food legume originating from South America and the South-western parts of the United States. The crop is produced in many countries worldwide including South Africa. It is highly tolerant to drought and the seed contains a wide range of vitamins, minerals and protein of high nutritional quality. The genetic base of tepary bean is narrow but can be widened by chemical mutagenesis. However, there are no reports on the impact of chemical mutagenesis on the root nodulation and seed storage proteins in tepary bean. Therefore, this study was designed to examine root nodulation attributes and seed storage proteins of three tepary bean genotypes in the early mutagenic generations (M2 to M4) derived through treatment with varying doses (0.0, 0.5, 1.0, 1.5 and 2.0 v/v) of ethyl methanesulfonate (EMS). The experiment on root nodulation attributes was laid out as a 3 x 5 x 3 (genotypes x EMS doses x mutant generations) factorial design replicated three times. At harvest, shoot height (SHT), primary root length (PRL), dry weights (shoot, root and nodule), number of nodules per plant (NNP) and grain yield components such as the number of pods per plant (NPP) and number of seeds per pod (NSP) were measured. Highly significant (P≤0.01) dose effects were observed for SHT, PRL, shoot dry weight (SDW) and root dry weight (RDW). Highly significant (P≤0.01) interaction effects of mutant generation x genotype x dose were observed for NSP. A highly significant (P≤0.01) positive linear relationship was observed between the NNP and nodule dry weight (NDW). Increase in the PRL suggested that tepary bean mutants could be important in drought tolerance. EMS treatment led to an enhanced partitioning of dry matter (assimilates) to the shoots and roots. There was a three fold increase in most of the root nodulation traits at the 0.5% EMS dose.The Kjeldahl method was used for crude protein determination whereas the sodium dodecyl sulphate – polyacrylamide gel electrophoresis (SDS PAGE) was utilized in determining the protein banding patterns of the bean. There were highly significant (P≤0.01) differences among the genotypes in crude protein accumulation. Highly significant (P≤0.01) mutant generation x genotype x dose were observed for seed protein accumulation. ‘Genotype 3’ attained the highest protein content (24.23%) at 1.5% EMS dose in the M4 generation. EMS doses ≥0.5% positively stimulated protein accumulation in all genotypes but high EMS doses (2.0%) depressed protein content. There were significant variations in seed storage protein profiles among the genotypes and mutant generations. ‘Genotype 6’ showed a distinct 15.0kDa protein fragment which was absent in the majority of the remaining genotypes. The presence of distinct protein subunits in the three genotypes could be used in varietal
Open Access
Effect of genotype and phosphorus fertilizer rates on water use and yield of chickpea
(2013-12-09) Madzivhandila, Thendo; Ogola. J. B. O; Odhiambo. J. J. O.
Production of chickpea in South Africa is currently insignificant but local demand is high. There are no recommendations on suitable genotypes of chickpea and agronomic practices at present. This study aimed at evaluating the effect of genotype and phosphorus (P) fertilizer rates on water use and yield of four chickpea genotypes. A field experiment was undertaken, in winter 2009 and summer 2010, using a factorial arrangement of 3 P fertilizer rates (0, 45 and 90 kg P ha-1) and 4 chickpea genotypes (ICCV92944, ICCV3110, ICCV4306 and ICCV7307) laid in a randomized complete block design and replicated 3 times. Total crop biomass was determined at vegetative, 50% flowering, and harvest maturity (HM) stages and number of pods per plant, seeds per pod, 100 seed weight, grain yield and harvest index (HI) were determined at harvest maturity. Water use (ET) was determined by measuring soil moisture content at week intervals. eutron probe was used to measure soil moisture content every week after emergence until physiological maturity. Soil moisture value was used to determine crop water use. Water use efficiency was determined as the ratio of crop biomass or grain yield to water use (ET). Genotype and P fertilizer rates affected the crop biomass at vegetative and 50% flowering stage in season I and season II. Desi genotypes had greater crop biomass compared with kabuli genotypes in winter and summer season. Genotype did not affect crop biomass at harvest maturity in both winter and summer season but the application of phosphorus fertilizer rate significantly (P<0.01) affected crop biomass at harvest maturity in 1'. summer season. Genotype significantly affected grain yield in winter (P<0.05) and summer (P<0.01) se·ason. The desi types significantly had greater grain yield ( 1464 and 979 kg ha-1) compared with kabuli types (680 and 274 kg ha-1) in season I. In contrast, the kabuli types significantly had greater grain yield (1538 and 1396 kg ha-1) compared with desi types (1196 and 983 kg ha-I) in season II. Application of phosphorus fertilizer rates did not affect grain yield in season I probably due to water deficits in winter season. In contrast, P fertilizer application rates significantly (P<0.01) affected grain yield in season II.Phosphorus fertilizer at the rate of 90 kg P ha-1 produced significantly greater grain yield (1585.0 kg ha-I) followed by 45 kg P ha-I (1313.0 kg ha-1 and 0 kg P ha-1 (935.0 kg ha-1 in season II. Genotype and did not affect water use (ET) in season I (average 221.3 mm) and season II (average 314.2 mm). Phosphorus application also did not affect water use (ET) in season I (average 221.3 mm) and season II (average 314.2 mm). The desi types significantly had greater water use efficiency of grain yield (WUEg) (6.36 and 4.41 kg ha-1 mm-1) compared with kabuli types (2.69 and 1.33 kg ha-1 mm- 1) in season I. In contrast, the kabuli types significantly had greater water use efficiency of grain yield (WUEg) (4.90 and 4.40 kg ha-I mm-1) compared with desi types (3.41 and 3.12 kg ha-1 mm-I) in season II. Application of phosphorus fertilizer rates significantly (P<0.05) affected water use efficiency of grain yield (WUEg) in season I and season II. Application of phosphorus fertilizer at the rate of 90 kg p ha-I produced significantly greater water use efficiency of grain yield (WUEg) compared with 45, 0 kg P ha-1 Therefore desi genotypes may be more favourable in winter season. In contrast, kabuli appears to be more suitable in summer season while 45 and 90 kg P ha-1 phosphorus fertilizer rates may increase chickpea yield for the site of current study in both season and season II.
Open Access
The effect of phosphorus fertilizer and bradyrhizobium innoculation on grain yield and nutrients accumulation in two chickpea (Cicer aritienum L.) genotypes
(2020-07) Madzivhandila, Vhulenda; Ogola, J. B. O.; Maseko, S. T.
Chickpea (Cicer aritienum L.) is an ancient crop that originated in South-Eastern Turkey and belongs to the genus Cicer, tribe Cicereae, and family Fabaceae. Chickpea has the ability to fix atmospheric nitrogen (N) for its growth. However, chickpea productivity not only depends on N2 fixation or dry matter accumulation, but also the effectiveness of nutrient partitioning to seed, a key component to overall yield. There is a dearth of information on the effect of P with rhizobial inoculation in response of nutrients accumulation in the rhizosphere, shoots and grain of chickpea, especially when determined at different growth stages in the African continent. This study contributes knowledge on this crucial aspect which will likely lead to more other similar research reports in other settings. Therefore, the objectives of this study was to evaluate the effect of P fertilizer rates and rhizobial inoculation on yield and nutrients accumulation in two chickpea genotypes. Field experiments were conducted in winter 2017 and 2018 at University of Venda, Thohoyandou and University of Limpopo’s experiment farm, Syferkuil. Treatments consisted of a factorial combination of two rates of P fertilizer (0 and 90 kg P ha-1), two desi chickpea genotypes (ACC1 and ACC5) and two rhizobial inoculation levels (with and without rhizobiam strain). The treatments were laid out in a randomized complete block design (RCBD) and replicated three times on 22 April 2017 and 11 April 2018 (Syferkuil), 13 April 2017 and 29 April 2018 (Thohoyandou). Macronutrients including P, K, Ca, Mg were determined using the citric acid method. The total N concentration were determined by the micro-Kjeldahl method in both soil, shoots and grain. Zn was extracted using a di-ammonium ethylenediaminetetraacetic acid (EDTA) solution. The content of macronutrients (P, K, Ca, Mg, Ca, and Zn) in soil, shoots and grain was determined by first subjected to wet digestion (Mehlich, 1984). From the digest, various elements were read using relevant procedures. P contents was determined colorimetrically using a spectrophotometer. Yield and yield components were assessed at harvest maturity. Genotypes affected the accumulation of mineral elements in rhizosphere soil, shoots, grain and yield. Accession 5 performed better in most of nutrients elements compared to accession 1 in both seasons and sites. Application of phosphorus alone, and in combination with rhizobium inoculation increased the concentration of majority of nutrients in the rhizosphere. When the test accessions were grown at the Syferkuil and Thohoyandou study location in 2017, they showed significant differences in the concentration of N, P and K while Ca, Mg and Zn were similar in the rhizosphere. The concentrations of N, P and K were markedly higher in the rhizosphere of ACC5 compared to ACC1. In fact, the concentration of P was two-fold greater in the rhizosphere of ACC5 than ACC1. Accession 5 exhibited a markedly higher shoot dry weight, number and dry weight of pods, 100-seed weight, grain yield and harvest index compared to ACC1. P plus rhizobium inoculation, P, rhizobium inoculation affected grain yield and yield components of chickpea genotypes. This preliminary finding show that the combination of P and rhizobium inoculation affected the nutrients accumulation in the rhizosphere, shoots, grain, yield and yield components in both locations. Moreover, Thohoyandou had the highest nutrients accumulation on the rhizosphere, shoots, grain, yield and yield components compared to Syferkuil.