Stanford Mabasa
University of Zimbabwe, Crop Science, Faculty Member
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Research Interests: Agronomy, Biology, Allelopathy, Weed, Crop, and 4 moreVelvet, Mucuna Pruriens, Mucuna, and Dry Weight
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... Pages 435-441 in Proceedings of the 5th International Symposium of Parasitic Weeds, Nairobi (Ransom JK, Musselman, LJ, Worsham, AD, and Parker, C., eds). Londres, Mex-ico: CIMMYT. Riches CR 1988. ... Farmer Magazine 16 Oct 1970.... more
... Pages 435-441 in Proceedings of the 5th International Symposium of Parasitic Weeds, Nairobi (Ransom JK, Musselman, LJ, Worsham, AD, and Parker, C., eds). Londres, Mex-ico: CIMMYT. Riches CR 1988. ... Farmer Magazine 16 Oct 1970. Vasudeva Rao, MJ 1987. ...
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Research Interests: Agronomy, Biology, Allelopathy, Pearl, Sorghum, and 3 moreCultivar, Sweet Sorghum, and Sorghum bicolor
Late blight is caused by Phytopthora infestans (Mont.) de Bary which establishes quickly in Solanum esculentum L. (tomato); as a result, it makes the pathogen one of the most devastating plant diseases across the world. The control of... more
Late blight is caused by Phytopthora infestans (Mont.) de Bary which establishes quickly in Solanum esculentum L. (tomato); as a result, it makes the pathogen one of the most devastating plant diseases across the world. The control of late blight is difficult because P. infestans has advanced and complex enzymes and effecter molecules coded by avirulence genes. As such, a study was carried out at the University of Zimbabwe, Department of Plant Production Sciences and Technologies, between August 2018 and May 2019 to evaluate the efficacy of Moringa oleifera Lour. (moringa), Eucalyptus nigra R.T. Baker (gumtree), and Lantana camara L. (sensu lato) (lantana) extracts as biofungicides on late blight development on S. esculentum. The effect of acetone, ethyl acetate, and water extracts of M. oleifera, E. nigra, and L. camara on percent inhibition and radial growth were evaluated in the laboratory. In addition, the efficacy of different extract concentrations of M. oleifera, E. nigra, an...
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Research Interests: Agronomy, Plant Biology, Biology, Parasitism, Sorghum, and 3 moreSoil sciences, Infestation, and Striga
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The objective of this study was to determine the stability of Sorghum spp. tolerance to two Striga strains. This was stimulated by the observation that sorghum tolerant to Striga asiatica in a particular area could still lack the same... more
The objective of this study was to determine the stability of Sorghum spp. tolerance to two Striga strains. This was stimulated by the observation that sorghum tolerant to Striga asiatica in a particular area could still lack the same tolerance to a strain native to remote areas. Nine Sorghum bicolor genotypes and one Sorghum arundinaceaum (Wild sorghum) were subjected to two Striga asiatica strains sourced from Rushinga and Chiundura which are 500 km apart together with a control. A 3 × 10 factorial experiment was set up, arranged in a completely randomized design with three replications at two sites. The measured data were sorghum height, chlorophyll content, tiller number and dry matter. The results showed that sorghum genotype and Striga strain differed (P<0.05) in their response to the stunting effects of Striga strains at both the sites. The Chiundura strain was more virulent to Isifumbathe, Zambia, Wild sorghum and Mashava at Henderson Research Station, whilst at BUSE the Chiundura strain was more virulent on wild sorghum and Mashava. The two Striga strains were generally similar on their effects on chlorophyll content and were less than the control. However, different sorghum genotypes responded differently to the effects of various sorghum strains. At Henderson, the Chiundura strain reduced chlorophyll content of Chiredhi, Zambia, Tshwetha and SC Sila. At BUSE both strains were not significantly different (P<0.01) from each other at 10 weeks after crop emergence (WACE). The effects of the two strains were similar for head index, root index, stem index and leaf index at all sites. Chiundura strain reduced the total dry weight at BUSE but not at Henderson. Overally, the Chiundura strain had more deleterious effects on sorghum traits compared to Rushinga confirming the existence of physiological speciation on Striga asiatica.
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EThOS - Electronic Theses Online ServiceGBUnited Kingdo
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... Pages 435-441 in Proceedings of the 5th International Symposium of Parasitic Weeds, Nairobi (Ransom JK, Musselman, LJ, Worsham, AD, and Parker, C., eds). Londres, Mex-ico: CIMMYT. Riches CR 1988. ... Farmer Magazine 16 Oct 1970.... more
... Pages 435-441 in Proceedings of the 5th International Symposium of Parasitic Weeds, Nairobi (Ransom JK, Musselman, LJ, Worsham, AD, and Parker, C., eds). Londres, Mex-ico: CIMMYT. Riches CR 1988. ... Farmer Magazine 16 Oct 1970. Vasudeva Rao, MJ 1987. ...
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(African Crop Science Journal 1999 7(4): 321-326
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ABSTRACT
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Weed infestation is considered as one of the major biotic stresses of dryland crop production. Weed species occurrence, abundance, and densities differ due to spatial soil fertility variability, and management practices by farmers. Weed... more
Weed infestation is considered as one of the major biotic stresses of dryland crop production. Weed species occurrence, abundance, and densities differ due to spatial soil fertility variability, and management practices by farmers. Weed surveys are therefore vital for tracking such changes and in turn developing appropriate weed management strategies for farmers. A weed survey was carried out in Wedza, eastern Zimbabwe to assess farmer knowledge and perceptions of major weeds in maize fields across catena landscape positions. A multistage sampling procedure was used, involving random sampling of six villages within a 20 km radius, divided according to the catena position and economic status of the farmer. Two hundred and forty-nine (249) households were interviewed using a structured questionnaire. The data were coded and processed using the CSPro software package, and then analysed using the SPSS program. Factors that predicted the spatial distribution of weeds were determined usin...
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Maize (Zea mays L.) is an important staple food crop in sub-Saharan Africa (SSA) and contributes significantly to food security. Due to Striga, maize yield loss is estimated between 20 and 80% forcing some farmers to abandon their land... more
Maize (Zea mays L.) is an important staple food crop in sub-Saharan Africa (SSA) and contributes significantly to food security. Due to Striga, maize yield loss is estimated between 20 and 80% forcing some farmers to abandon their land therefore threatening food security. Many strategies have been applied to combat Striga infested fields to improve maize yields but alternative feasible approaches are still required. This study aimed at determining effects of phosphorus (P) and maize variety on Striga asiatica germination and attachment. A factorial experiment of eight P levels (0, 10, 20, 30, 40, 50, 60 and 70 kg ha−1), six maize varieties and Striga (inoculated and non-inoculated) in a 4 × 24 α-lattice design with three replications was set in a glasshouse at the University of Zimbabwe. A similar experiment was set under laboratory conditions using agar gel plates to determine S. asiatica germination using a complete randomized design with three replications. Adding P (at 40 kg ha−...
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Rotation of sorghum (Sorghum bicolor L. Moench) with sesame (Sesamum indicum L.) in drought prone areas of Zimbabwe has raised concerns on whether these two crops are compatible in the rotational system. This is because sorghum is known... more
Rotation of sorghum (Sorghum bicolor L. Moench) with sesame (Sesamum indicum L.) in drought prone areas of Zimbabwe has raised concerns on whether these two crops are compatible in the rotational system. This is because sorghum is known to exhibit strong allelopathic effects on both crop and weed species. A greenhouse experiment was conducted to assess the effect of soil incorporated sorghum residues on the emergence and seedling growth of sesame and weeds. The emergence and early seedling growth of sesame and the weed significantly p < 0.05 increased with increases in the amount of soil incorporated sorghum residues. Incorporating 27.7 g of the ground sorghum herbage caused a stimulatory effect on the emergence and early seedling growth of the test species. Liquid chromatography-mass spectrometry revealed the presence of 6 probable allelochemicals in sorghum residues, namely, 4-methylaminobutyrate, C16 sphinganine, oleamide, tauroursdeoxycholic acid, pisatin, and anhalonidine. F...
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A greenhouse pot experiment was conducted at the University of Zimbabwe to screen six cowpea varieties for resistance to Alectravogelii infection. Emergence of A. vogeliiwas first detected 55 days after crop emergence. A. vogeliiemergence... more
A greenhouse pot experiment was conducted at the University of Zimbabwe to screen six cowpea varieties for resistance to Alectravogelii infection. Emergence of A. vogeliiwas first detected 55 days after crop emergence. A. vogeliiemergence was not significantly (P > 0.05) influenced by cowpea genotype. No differences (P > 0.05) in cowpea parameters that were measured were observed among the cowpea genotypes. However, A. vogeliiinfection significantly (P < 0.05) reduced cowpea shoot biomass and pod number by 57 % and 98 %, respectively. Infected cowpeas failed to produce any pods at all with the exception of cowpea cultivar C/83/4/6 and C/85/6/4. A similar trend of results was observed with grain yield. Root biomass was not significantly influenced by A. vogeliiinfection. A. vogelii infected cowpeas had significantly (P < 0.05) higher root /shoot ratio compared to uninfected plants. Based on results on A. vogeliiemergence and cowpea parameters collected in this study, it c...
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Weed control is a serious problem in smallholder conservation agriculture farming areas in Zimbabwe. Green Manure Cover Crops (GMCCs), which improve soil fertility and reduce weeds through allelopathy, are likely to reduce the cost of... more
Weed control is a serious problem in smallholder conservation agriculture farming areas in Zimbabwe. Green Manure Cover Crops (GMCCs), which improve soil fertility and reduce weeds through allelopathy, are likely to reduce the cost of weed control in these areas. A laboratory study was conducted at the University of Zimbabwe to investigate the effect of extracts of eleven GMCCs on the germination percentage, radicle and plumule length of Bidens pilosa, Eleusine indica and Pennisatum glaucum (pearl millet). A green house experiment was also done to determine the allelopathic potential of these GMCC extracts applied as soil incorporated residues on the emergence and dry matter production of E. indica, B. pilosa and Acanthospermum hispidum. GMCC extracts significantly reduced germination, radicle and plumule length of Pennisatum glaucum (P
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Spider plant ( Cleome gynandra L .) contributes considerably to the nutrition and medicines of communities in southern Africa. However, its utilisation is limited by its bitterness caused by condensed tannins. Unfortunately, processing... more
Spider plant ( Cleome gynandra L .) contributes considerably to the nutrition and medicines of communities in southern Africa. However, its utilisation is limited by its bitterness caused by condensed tannins. Unfortunately, processing options that reduce the bitterness also remove nutritionally and medicinally useful compounds. The objective of this study was to assess the genetic variability of condensed tannins and their association with bitterness in C. gynandra so as to devise variety recommendations for either direct utilisation or for breeding programmes in Zimbabwe. Total phenolic compounds and condensed tannins were quantified in five genotypes. The amount of total phenolic compounds were not significant, but quite significant (P<0.001) for condensed tannins. Genotype CGSKGP had the highest (0.49 mg g-1) and twice as much condensed tannins as CGKEX and CGSKP. Bitterness was positively correlated with the concentrations of condensed tannins (r=0.94, P<0.05), but not wi...
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Sesame (Sesamum indicum L.) production is lucrative to resource poor farmers in marginalised areas of Zimbabwe, although most farmers have reportedly been failing to derive maximum economic benefits from sesame production due to poor... more
Sesame (Sesamum indicum L.) production is lucrative to resource poor farmers in marginalised areas of Zimbabwe, although most farmers have reportedly been failing to derive maximum economic benefits from sesame production due to poor productivity. Low productivity has been attributed to several factors including challenges of weed control due to absence of registered herbicides for use in sesame in Zimbabwe. Laboratory enzyme assays were conducted using different sorghum aqueous leaf and stem extract concentrations at 0, 2.5, 5.0, 7.5, and 10.0% wv−1 to determine the effect of sorghum aqueous extracts on plant defense enzymes polyphenol oxidase (PPO), peroxidase (POD), and phenylalanine ammonia lyase (PAL) in sesame and selected weeds. Greenhouse experiments were conducted to assess the effect of sorgaab or sorgaab-Agil postemergence sprays on the seedling growth and physiology of sesame and weeds. The exposure of sesame, black jack, and goose grass to sorghum aqueous extracts cause...
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Parasitic weeds belonging to the Orobanchaceae family are a menace in Sub-Saharan African (SSA). Specifically, the two witchweeds from the genus Striga, S. hermonthica and S. asiatica, are jointly responsible for land abandonments and... more
Parasitic weeds belonging to the Orobanchaceae family are a menace in Sub-Saharan African (SSA). Specifically, the two witchweeds from the genus Striga, S. hermonthica and S. asiatica, are jointly responsible for land abandonments and cereal yield reductions in the SSA. Factorial experiments involving fourteen maize genotypes and two levels of Striga asiatica infestation (infested and noninfested) were conducted under pot and laboratory experiments at the Department of Plant Production Sciences and Technologies, University of Zimbabwe, during the 2014/2015 season. A 14 × 2 factorial pot experiment was arranged in a 7 × 4 α-lattice design replicated four times, whereas the laboratory agar gel was arranged in a complete randomized design with four replications. Results revealed significant differences ( p
Research Interests: Agronomy, Biology, Agriculture, Infestation, Germination, and 3 moreGermplasm, Striga, and Striga hermonthica
Sorghum (Sorghum bicolor L. Moench) production in sub-Saharan Africa is seriously constrained by both biotic and abiotic stresses. Among the biotic stresses is witchweed (Striga spp.), a noxious parasitic weed causing major damage in... more
Sorghum (Sorghum bicolor L. Moench) production in sub-Saharan Africa is seriously constrained by both biotic and abiotic stresses. Among the biotic stresses is witchweed (Striga spp.), a noxious parasitic weed causing major damage in cereal crops, such as sorghum. However, resistance through reduced germination stimulant production or altered germination stimulant composition provides a sustainable and most effective way for managing the parasitic weeds. Laboratory and glasshouse experiments were conducted using seven (7) sorghum genotypes to evaluate their resistance or tolerance the witch weed (Striga asiatica L. Kuntze). The first experiment was a laboratory agar gel assay arranged in a completely randomized design with six (6) replications to evaluate the effects of the seven (7) sorghum genotypes on the production of strigolactones by determining the percentage germination and the furthest germination distance of the Striga seeds. The second experiment was a seven (7) (sorghum ...
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Does 2,4-dichlorophenoxyacetic acid induce flowering in sweet potato?
Allelochemicals from sorghum [Sorghum bicolor (L.) Moench] residues may inhibit the emergence and growth of other crops. We examined the effects of residues from two sorghum landraces, IS9456, a high sorgoleone producer, and IS22320, a... more
Allelochemicals from sorghum [Sorghum bicolor (L.) Moench] residues may inhibit the emergence and growth of other crops. We examined the effects of residues from two sorghum landraces, IS9456, a high sorgoleone producer, and IS22320, a zero sorgoleone producer. Residues were applied at 7.2 g, 14.4 g and 21.6 g kg-1 of soil. Emergence and the growth of maize (Zea mays L.), wheat (Triticum aestivum L.) and soybean [Glycine max (L.) Merr.] were tested in three glasshouse pot experiments at the University of Zimbabwe in 2017. The 2×3 factorial experiments were laid as a randomized complete block design with six replications. Residues from IS22320 significantly (P 0.05) reduce the emergence, height, chlorophyll content or dry weight of soybean. Increasing the residue rate significantly (P<0.05) reduced the percent emergence, height, chlorophyll content and dry weight of soybean. There was a significant sorghum variety × residue application rate interaction on the percent emergence (P&...
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Maize (Zea mays L.) is a major staple crop in southern Africa and is produced on millions of hectares. However, its yield is greatly reduced by Striga spp, a parasitic weed which is causing US$ 7 billion losses annually. Use of host... more
Maize (Zea mays L.) is a major staple crop in southern Africa and is produced on millions of hectares. However, its yield is greatly reduced by Striga spp, a parasitic weed which is causing US$ 7 billion losses annually. Use of host resistance could be an effective way of controlling Striga and resistance to Striga is quantitative, mainly controlled by additive gene action. Understanding the population structure and genetic diversity is therefore key in designing an effective breeding program targeting grain yield heterosis and resistance to Striga. The aim of this study was to determine the genetic diversity and population structure of the key germplasm from tropical Africa. This information could guide in the identification of heterotic groups and potential testers required to kick start a maize breeding program for Striga asiatica in southern Africa. A total of 222 maize inbred lines from IITA and CIMMYT were used in this study. The materials were genotyped using the genotyping-b...
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Soybean has the potential to bring significant benefits in diversified cropping systems, which could help restructuring soil fertility and allow smallholders to increase grain yield. Rhizobium inoculation improves the biological nitrogen... more
Soybean has the potential to bring significant benefits in diversified cropping systems, which could help restructuring soil fertility and allow smallholders to increase grain yield. Rhizobium inoculation improves the biological nitrogen fixation (BNF) in legume crops and assists resource-poor farmers to increase grain yield at lower financial costs. The efficacy of symbiotic bacteria on legumes can also be improved through supplementation of phosphorus fertilizer. In this work, a meta-analysis of 29 peer-reviewed studies was performed to understand the effects of various Rhizobium strains and phosphate fertilizer application on soybean nodules. Results showed that Rhizobium inoculation was highly effective in increasing the number of soybean nodules, nodule dry weight, and shoot dry weight. Application of phosphorus fertilizer increased the overall nodule number due to improved BNF processes by Rhizobia. The main effects of both Rhizobium inoculation and phosphate fertilizer resul...
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Green manure cover crops (GMCCs), which are recommended for improving soil fertility, also have the potential of reducing weed populations in cropping systems through allelopathy. The objective of this study was to evaluate the effect of... more
Green manure cover crops (GMCCs), which are recommended for improving soil fertility, also have the potential of reducing weed populations in cropping systems through allelopathy. The objective of this study was to evaluate the effect of eight GMCCs on the germination and seedling development of two weeds of divergent morphology, namely, goose grass [Eleusine indica (L.) Gaertn] and blackjack (Bidens pilosa L.). Aqueous leaf, stem, and root extracts of hyacinth bean (Lablab purpureus L), red sunnhemp [Crotalaria ochroleuca (G.) Don], showy rattlebox (Crotalaria grahamiana Wight & Arn.), common bean (Phaseolus vulgaris L.), common rattlepod (Crotalaria spectabilis Roth.), radish (Raphanus sativus L.), tephrosia (Tephrosia vogelii L.), and black sunnhemp (Crotalaria juncea L.) at 0, 1.25, 2.5, 3.75, and 5% wv−1 were applied to weed seeds in Petri dishes to determine their effect on germination, radicle and plumule growth, and germination vigor index. The experimental design was 3(tiss...
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Labour bottlenecks and multiple operations at the start of a cropping season often result in inadequate early weed control and subsequent poor crop performance. Therefore, there is a need to establish management practices that provide the... more
Labour bottlenecks and multiple operations at the start of a cropping season often result in inadequate early weed control and subsequent poor crop performance. Therefore, there is a need to establish management practices that provide the best opportunities for the gains associated with weeding and nutrient management across farms. We investigated the influence of soil organic carbon (SOC), fertiliser management, and weeding regimes on weed dynamics and maize productivity on smallholder farms with contrasting SOC in eastern Zimbabwe. On each site, and for two seasons, a 2 × 5 factorial experiment laid in a randomised complete block design was used. Fertiliser management was NPK or NPK + cattle manure (CM); weeding regimes were herbicide + hoe weeding, hoe weeding thrice/twice/once, or weedy check. Principal component analysis was used to evaluate weed density. The grain yield of maize increased by 13% on the sites with higher SOC. Integrating NPK + CM increased weed density and maize grain yield by 1.32 and 1.46-times, respectively, compared with NPK application only. The increased maize yield from fertiliser-managed treatments occurred only in early frequently weeded treatments. However, fertiliser application had little effect when weeding was delayed, as maize yield instead declined by 40–80%. We concluded that higher SOC increased weed density and weed biomass. Smallholder farmers are encouraged to combine herbicide application combined with hoe-weeding options for sustainable maize production.