Alice Mweetwa - Academia.edu (original) (raw)

Papers by Alice Mweetwa

World Mycotoxin Journal, May 3, 2023

Mycotoxins are the most notorious compounds contaminating food crops in the production chains, in... more Mycotoxins are the most notorious compounds contaminating food crops in the production chains, in which cereals and nuts are primarily infected. The present study was aimed at determining multi-mycotoxins in maize grain samples collected at post-harvest stages across the main maize producing districts of Ethiopia. Then, 80 maize samples were collected from three districts (Bako, Ilu Gelan and Oda Bultum) and were analysed by LC-MS/MS. A total of 114 metabolites were with Penicillium and Aspergillus metabolites being positively identified in 26.3 and 18.4% of the samples, respectively. Among the mycotoxins addressed by regulatory limits, deoxynivalenol was detected in 85% of samples with the maximum level of 2,530 μg/kg, while zearalenone was detected in 81%, with levels as high as 3,750 μg/kg. A marked difference was observed across the study locations in the study areas, in which significant difference (P<0.005) of mycotoxin contamination recorded. For instances, of the total sample, contamination was detected on 78.1% in Oda Bultum followed by Ilu Gelan which was detected on 73.7% of the total samples with less proportion of contaminated from Bako district (68.4%). Different mycotoxins of regulated, binding or masked and emerging mycotoxin were also simultaneously detected in the samples. Intervention strategies which can reduce mycotoxin contamination along the maize value chains are required to combat the mycotoxin problems. Further, multi-season studies over multiple agro-ecologies are suggested for the county.

Sustainable Agriculture Research, Jun 27, 2016

Soybean [Glycine max (L.) Merrill] is known for nitrogen fixation by rhizobia present in the soil... more Soybean [Glycine max (L.) Merrill] is known for nitrogen fixation by rhizobia present in the soil with which it establishes an efficient symbiosis. In Zambia, current rhizobial inoculants used in soybeans production are based on non-indigenous strains; this creates a need to isolate local strains that can be used for the development of local inoculants for soybeans in Zambian soils. This paper reports the isolation and characterization of rhizobial isolates from virgin and cultivated soils of the three agro-ecological regions of Zambia. Rhizobia were isolated using the Trap Method and characterized using selected morphological and biochemical markers. A total of 61 isolates were isolated on Yeast Extract Mannitol (YEM) agar medium. Isolates varied in colony form, color, margin and texture. From the 61 isolates from the three regions, 87 % were circular, 8 % irregular and 5 % punctuate in form with 100 % convex elevation. The isolates had 88% entire, 10% undulate and 2 % lobate colony margins with different colors-56 % cream, 24 % white, 11 % yellow, 5 % transparent and 3 % pink. Transparent colonies were peculiar to Region I and III while pink colonies were peculiar to Region III. All isolates produced mucous, were gram negative and rod shaped, a characteristic of rhizobial cells. None of the isolates could tolerate extremes of pH (4 and 9) in growth medium but grew well at pH 6.8. All isolates utilized glucose as a source of carbon. Based on the Bromothymol Blue (BTB) assay, 59 isolates were fast growing while two isolates from cultivated soils of region II were slow growing. The fast growing 59 isolates showed an acidic reaction changing the medium from green to yellow, while the others showed an alkaline reaction. Based on the results, the 59 fast-growers could be Ensifer fredii or/and Rhizobium tropici rather than Bradyrhizobium. However, further tests to confirm these findings using ketolactose, genetic characterization and inclusion of reference strains, are still needed and are being recommended here.

Cogent Food & Agriculture

Journal of Agricultural Science, 2022

For studying the effect of soil fertility management practices on N mineralization, urease activi... more For studying the effect of soil fertility management practices on N mineralization, urease activity and maize yield, replicated field trials were established in 2015 at Misamfu and Msekera agricultural research stations (ARS) representing two geo-climatic regions of Zambia. The soil at Msekera ARS is a sandy clay loam (SCL) from a Paleustult, while that at Misamfu is a loamy sand (LS) from a Kandiustult. The field trials had three categories of treatments namely legumes, traditional and conventional. The legumes group consisted of researcher-recommended legume-cereal intercrop systems of maize with Cajanus cajan, Crotalaria juncea and Tephrosia vogelii in combination with compound D (10% N, 20% P2O5, 10% K2O) and urea (46% N) at the recommended rate (200 kg ha-1) and half of the recommended rate (100 kg ha-1). Composted cattle manure and Fundikila, a special plant biomass management technique, were the inputs under the traditional category. The conventional category consisted of a t...

African Journal of Plant Science, 2020

Good agricultural practices are an effective means of minimizing pre-harvest aflatoxin contaminat... more Good agricultural practices are an effective means of minimizing pre-harvest aflatoxin contamination in peanuts. A field experiment was conducted to evaluate the effect of gypsum on pod yield and aflatoxin contamination in three peanut cultivars (Kadononga, MGV 4 and MGV 5) in Zambia. The experiment was conducted in Chongwe and Lusaka districts. Gypsum (15.6 % calcium) was applied at rates of 0 and 400 kg/ha at flowering stage. Although gypsum had no significant effect on aflatoxin contamination, there were significant differences (p = 0.009) in cultivar susceptibility to aflatoxin contamination. The cultivar with the smallest kernels had 18.8% lower aflatoxin content than the large-kernelled cultivar. Additionally, gypsum did not have a clear effect on pod yield. For instance, gypsum was associated with 44.8% more grain-filled pods in Kadononga (p = 0.005) at the site in Lusaka, but this result did not apply to the other two cultivars. At the site in Chongwe, gypsum was associated with 34.6% higher pod yield of MGV 5 only (p = 0.006). These results further suggest that plant factors such as kernel size may have an influence on natural resistance to aflatoxin contamination in peanuts.

African Journal of Plant Science, 2019

Higher than acceptable aflatoxin levels in peanut kernels (Arachis hypogaea L.) and related produ... more Higher than acceptable aflatoxin levels in peanut kernels (Arachis hypogaea L.) and related products is a worldwide food safety concern. Strict regulatory standards by major importers of peanuts limit the marketability of peanuts for many developing tropical countries including Zambia. The incidence of preharvest aflatoxins is strongly linked to soil and weather conditions during pod-development. This study aimed to formulate statistical models to predict total aflatoxin content in peanut kernels using selected environmental factors during pod development. Field experiments were conducted for two years during which the peanut crop was exposed to 84 combinations of ambient temperature, soil temperature and soil moisture content measured during the last 30 days of pod development. These data were used to formulate regression models to predict total aflatoxin content in peanut kernels. Simple linear regression models had R 2 values of 0.30 for maximum ambient temperature, 0.24 for soil temperature and 0.38 for soil moisture content. Combining soil moisture content and soil temperature in a multivariate regression model could explain 54% of the variation in total aflatoxin content while a combination of soil moisture content and maximum ambient temperature could only explain 46% of the variation in total aflatoxin content.

IV International Symposium on Seed, Transplant and Stand Establishment of Horticultural Crops; Translating Seed and Seedling Physiology into Technology, 2008

For commercial propagation, orchid seeds are germinated aseptically in vitro. Successful establis... more For commercial propagation, orchid seeds are germinated aseptically in vitro. Successful establishment is dependent on harvesting seeds that are sufficiently mature to develop into protocorms and sanitization procedures that minimize contamination in culture. However, there are no standardized procedures for sanitizing orchid seeds and there is insufficient information about the optimum state of orchid seed development for best germination. Phalaenopsis amabilis fruits 90, 105, and 120 days after pollination (DAP), surface treated with 15% calcium hypochlorite (CH) for 30 min, were compared with seeds treated with 0, 5, 10, or 15% CH for 5, 10, or 15 min. Ninety six percent of untreated seeds from 90 DAP fruit, surface sanitized with 15% CH, produced protocorms within 40 days after sowing (DAS). Seed sanitization with 5% CH and exposure durations greater than 5 min significantly reduced protocorm percentages. Seeds treated with 10 or 15% CH showed inhibited protocorm development at all exposure times. Protocorms developed root hairs and shoot primodia by 50 DAS and an average of one leaf and root by 85 DAS after treatment with either 0 or 5% CH. Only 27 and 22% of seeds developed into protocorms but not roots or shoots following treatment with 10 or 15% CH, respectively. P. amabilis flowers were hand pollinated and fruits harvested 90, 105, and 120 DAP while still green for seed developmental analysis. Cell number per seed was estimated by counting nuclei stained with 4'-6-diamidino-2phenylindole using confocal microscopy. Germination percentage and cell number per embryo increased from 14 to 61% and 41 to 66%, respectively, during fruit development from 90 to 120 DAP. Harvesting fruits 120 DAP while still green and using fruit sanitization before plating seeds produced the highest percentage of protocorms. Seed sanitation with greater than 5% CH dramatically reduced protocorm and seedling development.

Plant Genetic Resources, 2012

Cowpea is an important grain legume crop in sub-Saharan Africa (SSA) where, on a worldwide basis,... more Cowpea is an important grain legume crop in sub-Saharan Africa (SSA) where, on a worldwide basis, the bulk is produced and consumed. The dry savanna area of SSA is where cowpea is mostly grown under rain-fed conditions. The crop is therefore prone to drought which may occur early, mid and/or late in the cropping season. Compared with many other crops, cowpea is drought tolerant, even though drought is still a major constraint limiting its productivity in SSA. Increasing the level of drought tolerance in existing cowpea varieties grown by farmers would enable them to obtain more and stable yield from their cowpea fields. As a first step towards enhancing drought tolerance in existing cowpea varieties, 1288 lines were selected randomly from cowpea germplasm collections maintained at the International Institute of Tropical Agriculture, and evaluated for their drought tolerance at Ibadan. Drought was imposed by withdrawal of irrigation from 5 weeks after sowing. On average, drought redu...

Irrigation and Drainage, 2020

Expanding arable land under irrigation is cardinal in the quest to attain Africa's aspiration... more Expanding arable land under irrigation is cardinal in the quest to attain Africa's aspiration of transforming agriculture and realizing its true value and positive impact on wealth creation, economic growth, food security and nutrition for all. Over the last three to four decades, many initiatives have been designed to harness both small‐ and large‐scale irrigation technologies towards increasing agricultural production and productivity. The EAU4Food (European Union and African Union cooperative research to increase food production in irrigated farming systems in Africa) project was a collaborative project under the EU–African Union Scientific Partnership aimed at enabling the successful adoption and upscaling of appropriate irrigation support innovations. The project applied a transdisciplinary approach to design, test and disseminate innovations across the continent. The project was designed to gain better insights vis‐à‐vis how the innovation process can be enhanced, and to s...

International Journal of Environment, Agriculture and Biotechnology, 2018

Understanding morpho-physiological factors associated with yield decline at high density in soybe... more Understanding morpho-physiological factors associated with yield decline at high density in soybean (Glycine max L.) can assist in optimizing productivity and seed quality. The objective of this study was to determine effects of different spacing on development and seed quality. The study tested the concept of yield plasticity. Five varieties that included determinate (SC Safari, Dina and Magoye) and indeterminate (Kaleya and Pan 1867) and three densities (300,000, 400,000 and 550,000 plants/ha) were used. A randomized complete block design arranged in 2 factor-factorial with variety and plant density and 4 replications was used. The experiment was done at Seed Control and Certification Institute in Chilanga, Zambia in 2015. Parameters assessed included: height, branches/plant, chlorophyll, nitrogen, 50 % flowering, pod-fill time, maturity duration, biomass, seed quality, yield and yield components.

Irrigation and Drainage, 2020

Boosting the productivity of smallholder farming systems continues to be a major need in Africa. ... more Boosting the productivity of smallholder farming systems continues to be a major need in Africa. Challenges relating to how to improve irrigation are multi-factor and multisectoral, and they involve a broad range of actors who must interact to reach decisions collectively. We provide a systematic reflection on findings from the research project EAU4Food, which adopted a transdisciplinary approach to irrigation for food security research in five case studies in Ethiopia,

Peanut Science, 2019

Peanut production in Zambia is often characterized by low yields and high aflatoxin incidence in ... more Peanut production in Zambia is often characterized by low yields and high aflatoxin incidence in harvested kernels. Soil amendments such as farmyard manure have shown potential to increase yields and reduce pre-harvest aflatoxin incidence. The aim of the current study was to evaluate the effects of composted cattle manure on soil properties that relate to yield and pre-harvest aflatoxin contamination of peanut kernels. Research evaluated the effects of composted cattle manure on soil respiration, plant-available water (PAW), peanut yield and pre-harvest aflatoxin contamination in a field experiment conducted in two successive rain-fed cropping seasons starting in December, 2015 and ending in April 2017, in Chongwe District, Zambia. Six (6) levels of compost were incorporated into the top 10 cm of the soil at rates of 0, 4.5, 12.0, 19.5, 27.0, and 34.5 metric tons/ha 1 wk before planting. There was a strong positive relationship between levels of compost and soil microbial respiratio...

Achieving sustainable cultivation of grain legumes Volume 2, 2018

Non-PRIFPRI4MTI

The occurrence of toxic concentrations of aflatoxin in peanuts requires appropriate intervention.... more The occurrence of toxic concentrations of aflatoxin in peanuts requires appropriate intervention. In countries such as Zambia with poor implementation of existing regulatory standards, consumer action can minimize risk of exposure. The current study evaluated the significance manual removal of shriveled, externally-discolored, misshapen, mechanically-damaged and insect-damaged kernels to minimize the baseline aflatoxin content in peanut samples. One hundred and two (102) aflatoxin-contaminated samples of raw peanuts each weighing 1 kg were collected. Each sample was sub-divided into two 500 g- subsamples of which one was manually sorted to remove contaminated kernels before the paired samples were each tested for total aflatoxin content. Results of a paired sample t-test showed an average of 56% reduction in mean total aflatoxin content from an initial 10.4 µg/kg (range of 5.2 to 18 µg/kg). Although manual sorting can be tedious for large lots and may not remove contaminated but vi...

African Journal of Agricultural Research, 2018

The effects of amending soil with gypsum and biochar on groundnut chlorophyll concentration, wate... more The effects of amending soil with gypsum and biochar on groundnut chlorophyll concentration, water use efficiency (WUE), biomass yield and selected soil properties were investigated under water stress. Gypsum (CaSO 4 .2H 2 O) was applied at 0 and 200 kg/ha, groundnut shell biochar at 1, 2 and 4% w/w of soil, and water at 100, 70 and 40% of daily plant water requirement (PWR) as main, sub and sub-sub plots, respectively, in a split-split-plot design. Biochar neutralized the acid soil, significantly raising soil pH from 5 to 7.15 and increasing cation exchange capacity by 75%. Biochar amended at 1 and 2%, increased groundnut dry matter yield by 28%. The optimum biochar application rate for dry matter yield was 1.4% w/w. Biochar application at 4% and irrigation at 40% of PWR reduced the WUE by 45 and 50%, respectively. Chlorophyll concentration index was highest at 40% of PWR. The results suggest that biochar has potential to raise soil pH, increase moisture retention and improve crop performance. Applying water at 100% PWR can increase groundnut dry matter yields, while higher gypsum application rates may be required to affect crop performance.

Journal of Agricultural Science, May 6, 2018

This paper reports the impacts of a four-year maize-cowpea rotation under conservation farming on... more This paper reports the impacts of a four-year maize-cowpea rotation under conservation farming on selected soil chemical, physical and biological properties with or without 100 kg/ha of Nitrogen: Phosphorus: Potassium: Sulphur (10:20:10:65) compound fertilizer. The study took advantage of an already established 4-year maize-cowpea rotation site and a maize monocrop field from which soil samples were collected for selected chemical, physical and biological analyses, and for setting up a greenhouse experiment for the determination of biological nitrogen fixation capabilities of cowpea. The results suggest that maize-cowpea rotations and addition of fertilizer influence particular chemical, physical and biological attributes of the soil in a varied manner. Rotating maize and cowpea has no influence on soil reaction, soil organic carbon, micronutrients, and exchangeable bases except for potassium. However, the addition of fertilizer to the maize-cowpea rotation reduces total nitrogen, while increasing the levels of sulphur and phosphorus in both the rotation and maize monocrop. Soil bulk density, total porosity and infiltration rate are not influenced by the maize-cowpea rotation with or without fertilizer amendment. Rotating maize with cowpea without the addition of fertilizer can result in an increase in plant available water, an observation needing further study. It can also be concluded that maize-cowpea rotations can reduce microbial biomass, regardless of fertilizer amendment, thus suggesting a need to understand maize and cowpea rhizopheric attributes affecting microbial biomass levels. Under the current conditions, the amount of biologically fixed nitrogen by cowpea is reduced by the application of fertilizer but not influenced by the rotation. Since these findings are based on four-year crop rotation, it is being recommended that further work be conducted to continue monitoring soil so as to factor in the effect of length of time.

World Mycotoxin Journal, May 3, 2023

Mycotoxins are the most notorious compounds contaminating food crops in the production chains, in... more Mycotoxins are the most notorious compounds contaminating food crops in the production chains, in which cereals and nuts are primarily infected. The present study was aimed at determining multi-mycotoxins in maize grain samples collected at post-harvest stages across the main maize producing districts of Ethiopia. Then, 80 maize samples were collected from three districts (Bako, Ilu Gelan and Oda Bultum) and were analysed by LC-MS/MS. A total of 114 metabolites were with Penicillium and Aspergillus metabolites being positively identified in 26.3 and 18.4% of the samples, respectively. Among the mycotoxins addressed by regulatory limits, deoxynivalenol was detected in 85% of samples with the maximum level of 2,530 μg/kg, while zearalenone was detected in 81%, with levels as high as 3,750 μg/kg. A marked difference was observed across the study locations in the study areas, in which significant difference (P<0.005) of mycotoxin contamination recorded. For instances, of the total sample, contamination was detected on 78.1% in Oda Bultum followed by Ilu Gelan which was detected on 73.7% of the total samples with less proportion of contaminated from Bako district (68.4%). Different mycotoxins of regulated, binding or masked and emerging mycotoxin were also simultaneously detected in the samples. Intervention strategies which can reduce mycotoxin contamination along the maize value chains are required to combat the mycotoxin problems. Further, multi-season studies over multiple agro-ecologies are suggested for the county.

Sustainable Agriculture Research, Jun 27, 2016

Soybean [Glycine max (L.) Merrill] is known for nitrogen fixation by rhizobia present in the soil... more Soybean [Glycine max (L.) Merrill] is known for nitrogen fixation by rhizobia present in the soil with which it establishes an efficient symbiosis. In Zambia, current rhizobial inoculants used in soybeans production are based on non-indigenous strains; this creates a need to isolate local strains that can be used for the development of local inoculants for soybeans in Zambian soils. This paper reports the isolation and characterization of rhizobial isolates from virgin and cultivated soils of the three agro-ecological regions of Zambia. Rhizobia were isolated using the Trap Method and characterized using selected morphological and biochemical markers. A total of 61 isolates were isolated on Yeast Extract Mannitol (YEM) agar medium. Isolates varied in colony form, color, margin and texture. From the 61 isolates from the three regions, 87 % were circular, 8 % irregular and 5 % punctuate in form with 100 % convex elevation. The isolates had 88% entire, 10% undulate and 2 % lobate colony margins with different colors-56 % cream, 24 % white, 11 % yellow, 5 % transparent and 3 % pink. Transparent colonies were peculiar to Region I and III while pink colonies were peculiar to Region III. All isolates produced mucous, were gram negative and rod shaped, a characteristic of rhizobial cells. None of the isolates could tolerate extremes of pH (4 and 9) in growth medium but grew well at pH 6.8. All isolates utilized glucose as a source of carbon. Based on the Bromothymol Blue (BTB) assay, 59 isolates were fast growing while two isolates from cultivated soils of region II were slow growing. The fast growing 59 isolates showed an acidic reaction changing the medium from green to yellow, while the others showed an alkaline reaction. Based on the results, the 59 fast-growers could be Ensifer fredii or/and Rhizobium tropici rather than Bradyrhizobium. However, further tests to confirm these findings using ketolactose, genetic characterization and inclusion of reference strains, are still needed and are being recommended here.

Cogent Food & Agriculture

Journal of Agricultural Science, 2022

For studying the effect of soil fertility management practices on N mineralization, urease activi... more For studying the effect of soil fertility management practices on N mineralization, urease activity and maize yield, replicated field trials were established in 2015 at Misamfu and Msekera agricultural research stations (ARS) representing two geo-climatic regions of Zambia. The soil at Msekera ARS is a sandy clay loam (SCL) from a Paleustult, while that at Misamfu is a loamy sand (LS) from a Kandiustult. The field trials had three categories of treatments namely legumes, traditional and conventional. The legumes group consisted of researcher-recommended legume-cereal intercrop systems of maize with Cajanus cajan, Crotalaria juncea and Tephrosia vogelii in combination with compound D (10% N, 20% P2O5, 10% K2O) and urea (46% N) at the recommended rate (200 kg ha-1) and half of the recommended rate (100 kg ha-1). Composted cattle manure and Fundikila, a special plant biomass management technique, were the inputs under the traditional category. The conventional category consisted of a t...

African Journal of Plant Science, 2020

Good agricultural practices are an effective means of minimizing pre-harvest aflatoxin contaminat... more Good agricultural practices are an effective means of minimizing pre-harvest aflatoxin contamination in peanuts. A field experiment was conducted to evaluate the effect of gypsum on pod yield and aflatoxin contamination in three peanut cultivars (Kadononga, MGV 4 and MGV 5) in Zambia. The experiment was conducted in Chongwe and Lusaka districts. Gypsum (15.6 % calcium) was applied at rates of 0 and 400 kg/ha at flowering stage. Although gypsum had no significant effect on aflatoxin contamination, there were significant differences (p = 0.009) in cultivar susceptibility to aflatoxin contamination. The cultivar with the smallest kernels had 18.8% lower aflatoxin content than the large-kernelled cultivar. Additionally, gypsum did not have a clear effect on pod yield. For instance, gypsum was associated with 44.8% more grain-filled pods in Kadononga (p = 0.005) at the site in Lusaka, but this result did not apply to the other two cultivars. At the site in Chongwe, gypsum was associated with 34.6% higher pod yield of MGV 5 only (p = 0.006). These results further suggest that plant factors such as kernel size may have an influence on natural resistance to aflatoxin contamination in peanuts.

African Journal of Plant Science, 2019

Higher than acceptable aflatoxin levels in peanut kernels (Arachis hypogaea L.) and related produ... more Higher than acceptable aflatoxin levels in peanut kernels (Arachis hypogaea L.) and related products is a worldwide food safety concern. Strict regulatory standards by major importers of peanuts limit the marketability of peanuts for many developing tropical countries including Zambia. The incidence of preharvest aflatoxins is strongly linked to soil and weather conditions during pod-development. This study aimed to formulate statistical models to predict total aflatoxin content in peanut kernels using selected environmental factors during pod development. Field experiments were conducted for two years during which the peanut crop was exposed to 84 combinations of ambient temperature, soil temperature and soil moisture content measured during the last 30 days of pod development. These data were used to formulate regression models to predict total aflatoxin content in peanut kernels. Simple linear regression models had R 2 values of 0.30 for maximum ambient temperature, 0.24 for soil temperature and 0.38 for soil moisture content. Combining soil moisture content and soil temperature in a multivariate regression model could explain 54% of the variation in total aflatoxin content while a combination of soil moisture content and maximum ambient temperature could only explain 46% of the variation in total aflatoxin content.

IV International Symposium on Seed, Transplant and Stand Establishment of Horticultural Crops; Translating Seed and Seedling Physiology into Technology, 2008

For commercial propagation, orchid seeds are germinated aseptically in vitro. Successful establis... more For commercial propagation, orchid seeds are germinated aseptically in vitro. Successful establishment is dependent on harvesting seeds that are sufficiently mature to develop into protocorms and sanitization procedures that minimize contamination in culture. However, there are no standardized procedures for sanitizing orchid seeds and there is insufficient information about the optimum state of orchid seed development for best germination. Phalaenopsis amabilis fruits 90, 105, and 120 days after pollination (DAP), surface treated with 15% calcium hypochlorite (CH) for 30 min, were compared with seeds treated with 0, 5, 10, or 15% CH for 5, 10, or 15 min. Ninety six percent of untreated seeds from 90 DAP fruit, surface sanitized with 15% CH, produced protocorms within 40 days after sowing (DAS). Seed sanitization with 5% CH and exposure durations greater than 5 min significantly reduced protocorm percentages. Seeds treated with 10 or 15% CH showed inhibited protocorm development at all exposure times. Protocorms developed root hairs and shoot primodia by 50 DAS and an average of one leaf and root by 85 DAS after treatment with either 0 or 5% CH. Only 27 and 22% of seeds developed into protocorms but not roots or shoots following treatment with 10 or 15% CH, respectively. P. amabilis flowers were hand pollinated and fruits harvested 90, 105, and 120 DAP while still green for seed developmental analysis. Cell number per seed was estimated by counting nuclei stained with 4'-6-diamidino-2phenylindole using confocal microscopy. Germination percentage and cell number per embryo increased from 14 to 61% and 41 to 66%, respectively, during fruit development from 90 to 120 DAP. Harvesting fruits 120 DAP while still green and using fruit sanitization before plating seeds produced the highest percentage of protocorms. Seed sanitation with greater than 5% CH dramatically reduced protocorm and seedling development.

Plant Genetic Resources, 2012

Cowpea is an important grain legume crop in sub-Saharan Africa (SSA) where, on a worldwide basis,... more Cowpea is an important grain legume crop in sub-Saharan Africa (SSA) where, on a worldwide basis, the bulk is produced and consumed. The dry savanna area of SSA is where cowpea is mostly grown under rain-fed conditions. The crop is therefore prone to drought which may occur early, mid and/or late in the cropping season. Compared with many other crops, cowpea is drought tolerant, even though drought is still a major constraint limiting its productivity in SSA. Increasing the level of drought tolerance in existing cowpea varieties grown by farmers would enable them to obtain more and stable yield from their cowpea fields. As a first step towards enhancing drought tolerance in existing cowpea varieties, 1288 lines were selected randomly from cowpea germplasm collections maintained at the International Institute of Tropical Agriculture, and evaluated for their drought tolerance at Ibadan. Drought was imposed by withdrawal of irrigation from 5 weeks after sowing. On average, drought redu...

Irrigation and Drainage, 2020

Expanding arable land under irrigation is cardinal in the quest to attain Africa's aspiration... more Expanding arable land under irrigation is cardinal in the quest to attain Africa's aspiration of transforming agriculture and realizing its true value and positive impact on wealth creation, economic growth, food security and nutrition for all. Over the last three to four decades, many initiatives have been designed to harness both small‐ and large‐scale irrigation technologies towards increasing agricultural production and productivity. The EAU4Food (European Union and African Union cooperative research to increase food production in irrigated farming systems in Africa) project was a collaborative project under the EU–African Union Scientific Partnership aimed at enabling the successful adoption and upscaling of appropriate irrigation support innovations. The project applied a transdisciplinary approach to design, test and disseminate innovations across the continent. The project was designed to gain better insights vis‐à‐vis how the innovation process can be enhanced, and to s...

International Journal of Environment, Agriculture and Biotechnology, 2018

Understanding morpho-physiological factors associated with yield decline at high density in soybe... more Understanding morpho-physiological factors associated with yield decline at high density in soybean (Glycine max L.) can assist in optimizing productivity and seed quality. The objective of this study was to determine effects of different spacing on development and seed quality. The study tested the concept of yield plasticity. Five varieties that included determinate (SC Safari, Dina and Magoye) and indeterminate (Kaleya and Pan 1867) and three densities (300,000, 400,000 and 550,000 plants/ha) were used. A randomized complete block design arranged in 2 factor-factorial with variety and plant density and 4 replications was used. The experiment was done at Seed Control and Certification Institute in Chilanga, Zambia in 2015. Parameters assessed included: height, branches/plant, chlorophyll, nitrogen, 50 % flowering, pod-fill time, maturity duration, biomass, seed quality, yield and yield components.

Irrigation and Drainage, 2020

Boosting the productivity of smallholder farming systems continues to be a major need in Africa. ... more Boosting the productivity of smallholder farming systems continues to be a major need in Africa. Challenges relating to how to improve irrigation are multi-factor and multisectoral, and they involve a broad range of actors who must interact to reach decisions collectively. We provide a systematic reflection on findings from the research project EAU4Food, which adopted a transdisciplinary approach to irrigation for food security research in five case studies in Ethiopia,

Peanut Science, 2019

Peanut production in Zambia is often characterized by low yields and high aflatoxin incidence in ... more Peanut production in Zambia is often characterized by low yields and high aflatoxin incidence in harvested kernels. Soil amendments such as farmyard manure have shown potential to increase yields and reduce pre-harvest aflatoxin incidence. The aim of the current study was to evaluate the effects of composted cattle manure on soil properties that relate to yield and pre-harvest aflatoxin contamination of peanut kernels. Research evaluated the effects of composted cattle manure on soil respiration, plant-available water (PAW), peanut yield and pre-harvest aflatoxin contamination in a field experiment conducted in two successive rain-fed cropping seasons starting in December, 2015 and ending in April 2017, in Chongwe District, Zambia. Six (6) levels of compost were incorporated into the top 10 cm of the soil at rates of 0, 4.5, 12.0, 19.5, 27.0, and 34.5 metric tons/ha 1 wk before planting. There was a strong positive relationship between levels of compost and soil microbial respiratio...

Achieving sustainable cultivation of grain legumes Volume 2, 2018

Non-PRIFPRI4MTI

The occurrence of toxic concentrations of aflatoxin in peanuts requires appropriate intervention.... more The occurrence of toxic concentrations of aflatoxin in peanuts requires appropriate intervention. In countries such as Zambia with poor implementation of existing regulatory standards, consumer action can minimize risk of exposure. The current study evaluated the significance manual removal of shriveled, externally-discolored, misshapen, mechanically-damaged and insect-damaged kernels to minimize the baseline aflatoxin content in peanut samples. One hundred and two (102) aflatoxin-contaminated samples of raw peanuts each weighing 1 kg were collected. Each sample was sub-divided into two 500 g- subsamples of which one was manually sorted to remove contaminated kernels before the paired samples were each tested for total aflatoxin content. Results of a paired sample t-test showed an average of 56% reduction in mean total aflatoxin content from an initial 10.4 µg/kg (range of 5.2 to 18 µg/kg). Although manual sorting can be tedious for large lots and may not remove contaminated but vi...

African Journal of Agricultural Research, 2018

The effects of amending soil with gypsum and biochar on groundnut chlorophyll concentration, wate... more The effects of amending soil with gypsum and biochar on groundnut chlorophyll concentration, water use efficiency (WUE), biomass yield and selected soil properties were investigated under water stress. Gypsum (CaSO 4 .2H 2 O) was applied at 0 and 200 kg/ha, groundnut shell biochar at 1, 2 and 4% w/w of soil, and water at 100, 70 and 40% of daily plant water requirement (PWR) as main, sub and sub-sub plots, respectively, in a split-split-plot design. Biochar neutralized the acid soil, significantly raising soil pH from 5 to 7.15 and increasing cation exchange capacity by 75%. Biochar amended at 1 and 2%, increased groundnut dry matter yield by 28%. The optimum biochar application rate for dry matter yield was 1.4% w/w. Biochar application at 4% and irrigation at 40% of PWR reduced the WUE by 45 and 50%, respectively. Chlorophyll concentration index was highest at 40% of PWR. The results suggest that biochar has potential to raise soil pH, increase moisture retention and improve crop performance. Applying water at 100% PWR can increase groundnut dry matter yields, while higher gypsum application rates may be required to affect crop performance.

Journal of Agricultural Science, May 6, 2018

This paper reports the impacts of a four-year maize-cowpea rotation under conservation farming on... more This paper reports the impacts of a four-year maize-cowpea rotation under conservation farming on selected soil chemical, physical and biological properties with or without 100 kg/ha of Nitrogen: Phosphorus: Potassium: Sulphur (10:20:10:65) compound fertilizer. The study took advantage of an already established 4-year maize-cowpea rotation site and a maize monocrop field from which soil samples were collected for selected chemical, physical and biological analyses, and for setting up a greenhouse experiment for the determination of biological nitrogen fixation capabilities of cowpea. The results suggest that maize-cowpea rotations and addition of fertilizer influence particular chemical, physical and biological attributes of the soil in a varied manner. Rotating maize and cowpea has no influence on soil reaction, soil organic carbon, micronutrients, and exchangeable bases except for potassium. However, the addition of fertilizer to the maize-cowpea rotation reduces total nitrogen, while increasing the levels of sulphur and phosphorus in both the rotation and maize monocrop. Soil bulk density, total porosity and infiltration rate are not influenced by the maize-cowpea rotation with or without fertilizer amendment. Rotating maize with cowpea without the addition of fertilizer can result in an increase in plant available water, an observation needing further study. It can also be concluded that maize-cowpea rotations can reduce microbial biomass, regardless of fertilizer amendment, thus suggesting a need to understand maize and cowpea rhizopheric attributes affecting microbial biomass levels. Under the current conditions, the amount of biologically fixed nitrogen by cowpea is reduced by the application of fertilizer but not influenced by the rotation. Since these findings are based on four-year crop rotation, it is being recommended that further work be conducted to continue monitoring soil so as to factor in the effect of length of time.