Crops In sub-Saharan Africa Research Articles

Profitability and market performance of smallholder potato enterprises in the Eastern Cape Province, South Africa

Potato (Solanum tuberosum) is one of the major staple crops and cash crops in sub-Saharan Africa. Its reputation continues to rise due to the increase in human population and the demand for potatoes is predictable. Potato-produce has a good market reputation and is the major source of household income in developing countries, especially South Africa. However, the increase in potato enterprise comes with its share of challenges that need to be addressed. Smallholder farmers in South Africa are still facing challenges in accessing and participating in lucrative and agro-food value chains, hence their farm returns are very low. There are very few research studies that have assessed the profitability and market performance of potato enterprises. Therefore, this study aimed to investigate the profitability of smallholder potato enterprises in the Eastern Cape Province. A multi-stage sampling procedure was employed to select 160 potato farmers. Primary data were collected using a structured questionnaire. Descriptive statistics, gross margin analysis, benefit-cost ratio and marketing margin analysis were used to analyze the data. The study results reveal that the potato enterprise is profitable and contributes to farmers' well-being. Farmers and sellers determined the price of potatoes. The reason for this market conduct is due to the weak characterization of smallholder farming. Performance analysis established that the total gross marketing and profit margins were highest when farmers sold potatoes to consumers and the lowest when farmers sold to middlemen and retailers. The study recommends that policymakers and government invest in improving infrastructure and educational training of farmers in terms of marketing and taking farming as agribusiness. The study further recommends that policymakers and farm organizations must strengthen institutions that take reliable and timely market information; established potato markets close to the farmers, especially those residing in rural areas. There must be a partnership established between research institutes and universities so that they constantly contribute by releasing high-yielding and disease-resistant varieties to advance the production and productivity of the vegetable sector. The study suggests that there is a need for government involvement to create strong market relations between farmers and consumers and to give suitable training to agricultural extension agents. Key words: Eastern Cape, Food security, Gross margin, Potato enterprise

Factors Affecting Sorghum Production in Western Ethiopia: Evidence from Smallholder Farmers

Sorghum is the most important cereal crop in Sub-Saharan Africa including Ethiopia. The productivity and production of the crop are not increased as expected due to many limitations in the generation of demand-driven technologies and innovation upscaling in integrated and impact-oriented approaches to sorghum production. The study was focused on sorghum production systems and factors affecting sorghum production for sorghum producers. For this study both purposive and random sampling techniques were applied to select 123 households. OLS regression was used to analyze factors affecting sorghum productivities. In the study areas, the majority of the farmers used the local sorghum variety. Only 17.89% of sample households used improved sorghum varieties including lalo, chemeda, and gemedi varieties. The technology attributes improved sorghum varieties were better performance than the local variety. The regression model revealed that variables including sex, age, education, improved variety, soil slope and fertility, TLU, and extension services affected sorghum productivity positively and significantly at 10%, 5%, and 1% significance levels. Respective experts (BoANR, research centers, NGOs, and Universities) should be advised and support sorghum producers to enhance sorghum productivity.

Exploring a mobile application for pest and disease symptomatic diagnosis in food crops in Nigeria: Implications of its use by smallholder farmers in sub-Saharan Africa

Crop pests and diseases are major impediments to food security in sub-Saharan Africa. Timely and accurate diagnosis of invasive crop pests and diseases promote crop protection efforts. The use of digital mobile application technology and image processing tools for precision agriculture and pest identification and monitoring is gaining attention but limited research has tested its accuracy, especially in sub-Saharan Africa. In this study, the accuracy of Plantix - your crop doctor (a general-purpose mobile application for plant pests and diseases diagnosis) was evaluated on common pests and diseases of some staple crops grown in South-Western Nigeria. The results showed 90-100% accuracy of major pest and disease symptoms detected on maize (Zea mays), okra (Abelmoschus esculenthus), cassava (Manihot esculenta), and plantain (Musa paradisiaca), and the application showed 100% accuracy when used to diagnose similar crop types, but that are healthy. However, pest symptoms on Celosia (Celosia argentea), Amaranth (Amaranthus sp.), and Roselle (Hibiscus sabdarifa) were not detected by the mobile application, probably because these crops were not yet included in the database of this application. The exploration of this mobile application can provide technical services for farmers. There is a need to update the database of Plantix with local and indigenous crops in sub-Saharan Africa and develop home-grown mobile applications for disease and pest diagnosis and monitoring.

Gene-editing technologies for developing climate resilient rice crops in sub-Saharan Africa: Political priorities and space for responsible innovation

Over the last 2 decades, rice has become one of the most important staple crops for sub-Saharan Africa. Estimates show that average consumption of rice has tripled over the last 3 decades, from 9.2 million metric tons (Mt) in the early 1990s to 31.5 million Mt in 2018, with West and Central Africa accounting for nearly two-thirds of this share. The demand for rice, however, has placed an enormous economic burden on African countries, whereby they spent over USD 5.5 billion per year on rice imports over the past few years. To address this challenge, over 32 countries have established National Rice Development Strategies to increase local production and to achieve rice self-sufficiency. Several of these countries have shown policy interest to use modern biotechnological advancements, including gene editing, to ensure increases in rice productivity and reduce food imports, in the context of extreme climate vulnerability and acceleration of the effects of biotic and abiotic stresses. This review article examines the role of biotechnology in African countries’ efforts to achieve rice self-sufficiency, particularly the potential for genome-editing technologies toward the genetic improvement of rice and to Africa’s nascent research programs. This article notes that while gene editing offers important advances in crop breeding, like genetic engineering, it faces some persistent sociopolitical challenges and low societal acceptability. As such, international partnerships advancing genome editing in Africa’s rice-subsectors development could benefit from adopting key principles from “responsible research and innovation” to help these projects achieve their potential, while bringing about more inclusive and reflexive processes that strive to anticipate the benefits and limits associated with new biotechnologies as they relate to local contexts. Such an approach could create the necessary political space to test and assess the benefits (and risks) related to adopting gene-editing technologies in Africa’s rice sectors.

Effects of Watering Regimes and Planting Density on Taro (Colocasia esculenta) Growth, Yield, and Yield Components in Embu, Kenya

Taro (Colocasia esculenta (L.) Schott) is one of the most underutilized crops in sub-Saharan Africa and an important staple food in the tropics. Understanding its growth response under selected watering regimes and planting densities underpins this research. A study was conducted at the Kenya Agricultural and Livestock Research Organization (KALRO), Embu Research Centre, during the long rains (LR) in 2021 and the short rains (SR) in 2021–2022. A factorial experiment with a split-plot layout arranged in a completely randomized block design was used. The main factor was the irrigation levels, while the subfactor was the planting density, with three replications. The three irrigation levels were at 100%, 60%, and 30% based on the field capacity (FC). The planting densities used were 0.5 m × 0.5 m (40,000 plants ha−1), 1 m × 0.5 m (20,000 plants ha−1), and 1 m × 1 m (10,000 plants ha−1), representative of high, medium, and low planting densities, respectively. Time and season ( P < 0.05 ) significantly influenced taro growth components (plant height, leaf area, leaf area index, and vegetative growth index) and yield components (corm length, corm diameter, corm mass, yield, and total biomass). Planting density influenced the leaf area and the leaf area index ( P < 0.05 ). The watering regime did not affect taro growth or yield components. Corm mass (0.59 kg), total biomass (49.8 t/ha), and yield (13.38 t/ha) were all the highest in the 30% FC. The 1 m × 0.5 m spacing produced the highest corm mass (0.62 kg). The high planting density (0.5 m × 0.5 m) resulted in the highest total biomass (70.2 t/ha), yield (20.84 t/ha), and harvest index (30.44%). As a result, the 0.5 m × 0.5 m planting density and 30% FC watering regime are recommended to farmers in the area for increased yields and food security.

Forgotten food crops in sub-Saharan Africa for healthy diets in a changing climate

As climate changes in sub-Saharan Africa (SSA), Africa's "forgotten" food crops offer a wide range of options to diversify major staple production as a key measure toward achieving zero hunger and healthy diets. So far, however, these forgotten food crops have been neglected in SSA's climate-change adaptation strategies. Here, we quantified their capacity to adapt cropping systems of SSA's major staples of maize, rice, cassava, and yams to changing climates for the four subregions of West, Central, East, and Southern Africa. We used climate-niche modeling to explore their potential for crop diversification or the replacement of these major staples by 2070, and assessed the possible effects on micronutrient supply. Our results indicated that approximately 10% of the present production locations of these four major staples in SSA may experience novel climate conditions in 2070, ranging from a high of almost 18% in West Africa to a low of less than 1% in Southern Africa. From an initial candidate panel of 138 African forgotten food crops embracing leafy vegetables, other vegetables, fruits, cereals, pulses, seeds and nuts, and roots and tubers, we selected those that contributed most to covering projected future and contemporary climate conditions of the major staples' production locations. A prioritized shortlist of 58 forgotten food crops, able to complement each other in micronutrient provision, was determined, which covered over 95% of assessed production locations. The integration of these prioritized forgotten food crops in SSA's cropping systems will support the "double-win" of more climate-resilient and nutrient-sensitive food production in the region.

Assessing the Prospects of Remote Sensing Maize Leaf Area Index Using UAV-Derived Multi-Spectral Data in Smallholder Farms across the Growing Season

Maize (Zea Mays) is one of the most valuable food crops in sub-Saharan Africa and is a critical component of local, national and regional economies. Whereas over 50% of maize production in the region is produced by smallholder farmers, spatially explicit information on smallholder farm maize production, which is necessary for optimizing productivity, remains scarce due to a lack of appropriate technologies. Maize leaf area index (LAI) is closely related to and influences its canopy physiological processes, which closely relate to its productivity. Hence, understanding maize LAI is critical in assessing maize crop productivity. Unmanned Aerial Vehicle (UAV) imagery in concert with vegetation indices (VIs) obtained at high spatial resolution provides appropriate technologies for determining maize LAI at a farm scale. Five DJI Matrice 300 UAV images were acquired during the maize growing season, and 57 vegetation indices (VIs) were generated from the derived images. Maize LAI samples were collected across the growing season, a Random Forest (RF) regression ensemble based on UAV spectral data and the collected maize LAI samples was used to estimate maize LAI. The results showed that the optimal stage for estimating maize LAI using UAV-derived VIs in concert with the RF ensemble was during the vegetative stage (V8–V10) with an RMSE of 0.15 and an R2 of 0.91 (RRMSE = 8%). The findings also showed that UAV-derived traditional, red edge-based and new VIs could reliably predict maize LAI across the growing season with an R2 of 0.89–0.93, an RMSE of 0.15–0.65 m2/m2 and an RRMSE of 8.13–19.61%. The blue, red edge and NIR sections of the electromagnetic spectrum were critical in predicting maize LAI. Furthermore, combining traditional, red edge-based and new VIs was useful in attaining high LAI estimation accuracies. These results are a step towards achieving robust, efficient and spatially explicit monitoring frameworks for sub-Saharan African smallholder farm productivity.

Diversity Analysis for Grain Nutrient Content and Agronomic Traits among Newly Bred Striga-Resistant and Fusarium oxysporum f.sp. strigae (FOS)-Compatible Sorghum Genotypes

The parasitic weed, Striga species, is among the major causes of yield and quality losses of cereal and legume crops in sub-Saharan Africa. The development of nutritionally enhanced genetic resources with Striga resistance is an overriding consideration in sorghum breeding programs. The objective of this study was to determine the genetic variability among 12 elite and newly bred sorghum (Sorghum bicolor (L.) Moench) lines with variable Striga resistance for agronomic performance and nutritional traits. The sorghum genotypes were analyzed for protein, amino acid profiles, and selected minerals. For agronomic traits, significant variations were observed for yield per plant that varied from 51.74 to 15.12 g/plant, with a mean of 29.77 g/plant. The tested genotypes showed significant (p < 0.05) variation in protein, amino acid, iron, and zinc contents. The crude protein content varied from 9.59 to 13.60%, with a mean of 11.64%. The lysine values ranged from 1.13 to 3.08%, with a mean of 2.15%, while methionine content varied from 0.42 to 1.58%, with a mean of 0.87%. Iron content ranged from 35.26 to 156.32 mg/kg with a mean of 78.32 mg/kg, while zinc content varied from 14.45 to 44.46 mg/kg with a mean of 24.91 mg/kg. The following genotypes: AS1, PAN8816, 672, Macia, AS436, 3984 × 630, AS426 × 672, and 105 × 654 were identified as having superior agronomic and nutritional qualities for commercialization and sorghum breeding programs.

Does empowerment influence women’s willingness to pay for integrated pest management practices? A case study of mango growers in Zambia

Mango is an important fruit crop in sub-Saharan Africa (SSA), including Zambia, due to its nutritional value and contribution to food security. However, the invasive and mango-infesting fruit fly is a significant constraint in mango production. Therefore, icipe and partners developed and disseminated the integrated pest management package to curb this menace. The current study uses household-level data from 325 smallholder mango-growing households from selected regions in Zambia to evaluate how empowerment affects women's willingness to pay (WTP) for an Integrated Pest Management (IPM) package for the suppression of mango-infesting fruit flies. We used a double-bounded contingent valuation model to determine the association between Project-Level Women’s Empowerment in Agriculture Index (pro-WEAI), other social-economics factors, and WTP. The results show that women’s empowerment status positively and significantly increased the likelihood of considering a higher bid for the IPM package. Other factors affecting women’s WTP for the IPM package were women's education level, access to extension services, non-farm occupation, and household income from mangoes, with a positive and significant influence on their WTP. However, distance to the input market, perception of the effectiveness of current fruit fly management methods, and level of mango loss due to fruit flies negatively influenced WTP for the IPM package. Empowering women, especially increasing their access to extension services, and providing livelihood alternatives would increase their uptake of pest management technologies. Efforts to lower women’s domestic workloads, boost their finances, and sensitize others in the community to promote women’s freedom of movement would be vital to empowering women hence increasing their uptake of new agricultural innovations.

Estimating genetic gains for tolerance to stress combinations in tropical maize hybrids.

Maize is a strategic food crop in sub-Saharan Africa. However, most maize growing tropical savannas particularly in West and Central African experience the occurrence of frequent droughts and Striga infestation, resulting in 30-100% yield losses. This production zones need maize cultivars that combine tolerance to the two stresses. IITA in collaboration with national partners has thus employed a sequential selection scheme to incorporate both drought tolerance and Striga resistance in topical maize hybrids using reliable screening protocols. The main objective of the present study was therefore to use grain yield and other agronomic traits recorded in regional collaborative hybrid trials conducted for 8years under manged stressful and non-stressful conditions and across rainfed field environments to estimate genetic gains in grain yields using mixed model analyses. The results showed significant (p < 0.05) annual yield gains of 11.89kgha-1 under manged drought stress (MDS) and 86.60kgha-1 under Striga infestation (STRIN) with concomitant yield increases of 62.65kgha-1 under full irrigation (WW), 102.44kgha-1 under Striga non-infested (STRNO) conditions and 53.11kgha-1 across rainfed field environments. Grain yield displayed significant but not strong genetic correlation of 0.41 ± 0.07 between MDS and STRIN, indicating that gene expression was not consistent across the two stress conditions. Furthermore, grain yield recorded in MET had significant moderate genetic correlations of 0.58 ± 0.06 and 0.44 ± 0.07It with MDS and STRIN, respectively. These results emphasize the need to screen inbred linens under both stress conditions to further enhance the rate of genetic gain in grain yield in hybrids for areas where the two stresses co-occur. Nonetheless, this study demonstrated that the sequential selection scheme has been successful in generating hybrids with dependable yields that can reduce chronic food deficits in rural communities experiencing simultaneous presence of drought and S. hermonthica infestation in their production fields.

Back to the roots: defining the core microbiome of Sorghum bicolor in agricultural field soils from the centre of origin.

Sorghum is a major staple crop in sub-Saharan Africa with yields severely impacted by biotic and abiotic factors. Here, we analysed the taxonomic diversity and biogeographical distribution of bacterial taxa of 48 agricultural fields along a transect of approximately 2000km across the Ethiopian sorghum belt, the centre of origin of sorghum. The ultimate goal is to identify-yet-unexplored-beneficial plant-microbe associations. Based on bulk soil bacterial communities and DArT-SNP analyses of 59 sorghum accessions, we selected three microbiologically distinct field soils and 12 sorghum genotypes, including commercial varieties, wild relatives, and farmer-preferred landraces. The results showed a core rhizosphere microbiome of 2125 amplicon sequence variants (ASVs), belonging to eight bacterial families consistently found across the three soil types and the 12 sorghum genotypes. Integration of the rhizosphere bacterial community analysis with DArT-SNP sorghum genotyping revealed the association of differentially abundant ASVs with sorghum genotypic traits, including the distinct recruitment of Pseudomonadaceae by the stay-green, drought-tolerant, and wild sorghum genotypes. Collectively, these results provide new insights into the core and accessory bacterial taxa in the sorghum rhizosphere in the centre of origin, setting a baseline for targeted isolation and functional characterization of putative beneficial rhizobacteria.

Improving drought tolerance in maize: Tools and techniques.

Drought is an important constraint to agricultural productivity worldwide and is expected to worsen with climate change. To assist farmers, especially in sub-Saharan Africa (SSA), to adapt to climate change, continuous generation of stress-tolerant and farmer-preferred crop varieties, and their adoption by farmers, is critical to curb food insecurity. Maize is the most widely grown staple crop in SSA and plays a significant role in food security. The aim of this review is to present an overview of a broad range of tools and techniques used to improve drought tolerance in maize. We also present a summary of progress in breeding for maize drought tolerance, while incorporating research findings from disciplines such as physiology, molecular biology, and systems modeling. The review is expected to complement existing knowledge about breeding maize for climate resilience. Collaborative maize drought tolerance breeding projects in SSA emphasize the value of public-private partnerships in increasing access to genomic techniques and useful transgenes. To sustain the impact of maize drought tolerance projects in SSA, there must be complementary efforts to train the next generation of plant breeders and crop scientists.

Effects of intercropping sunn hemp into maize at different times and densities on productivity under rainwater harvesting technique

Maize is a major food crop in Sub-Saharan Africa (SSA), and its productivity is affected by climate change-adaptive sustainable management practices. A 2-year field study (2019/20 and 2020/21 growing seasons) was carried out to evaluate the effect of sunn hemp (Crotalaria junceaL.) living mulch management on maize (Zea maysL.) production. Three sunn hemp planting periods were simultaneous with maize planting (P1), V15 maize growth stage (P2), and R1 maize growth stage (P3) and three densities 16.1 plants m−2(D1-low), 32.1 plants m−2(D2-medium), and 48.1 plants m−2(D3-high). The intercrop components were planted in a split-plot treatment arrangement as an additive series with three replications and laid out in a randomized complete block design under the in-field rainwater harvesting (IRWH) technique. The growing season conditions revealed significant differences in rainfall distribution. Therefore, the planting period had highly significant (p&amp;lt; 0.001) effects on sunn hemp biomass, with an LSD value of 610.2 kg ha−1, showing that the highest was obtained in P2 (2636.7 kg ha−1) compared to P3 (811.3 kg ha−1). However, the P3 treatment resulted in maize grain yield penalty, with yields as follows: P3 (2775.2 kg ha−1), sole maize (3263.8 kg ha−1), P2 (3281.9 kg ha−1), and P1 (3287.8 kg ha−1). P2 yielded a significantly (p&amp;lt; 0.05) high-income equivalent ratio of 2.09, indicating a 109% advantage for increasing farmers' income by integrating sunn hemp under the no-till area of IRWH. P1 and P2 sunn hemp planting periods are viable options for smallholder farmers in summer rainfall regions to improve economic benefits.

Quantitative Trait Analysis Shows the Potential for Alleles from the Wild Species Arachis batizocoi and A. duranensis to Improve Groundnut Disease Resistance and Yield in East Africa

Diseases are the most important factors reducing groundnut yields worldwide. In East Africa, late leaf spot (LLS) and groundnut rosette disease (GRD) are the most destructive diseases of groundnut. Limited resistance is available in pure pedigree cultivated groundnut lines and novel sources of resistance are required to produce resistant new varieties. In this work, 376 interspecific lines from 3 different populations derived from crosses with the wild species A. duranensis, A. ipaënsis, A. batizocoi and A. valida were phenotyped for 2 seasons and across 2 locations, Serere and Nakabango, in Uganda. Several genotypes showed a higher yield, a larger seed, an earlier flowering, and similar resistance to the local cultivar checks. Genotypic data was used to construct a linkage map for the AB-QTL population involving the cross between Fleur11 and [A. batizocoi x A. duranensis]4x. This linkage map, together with the phenotypic data was used to identify quantitative trait loci controlling disease resistance. These lines will be useful in combining good agronomic traits and stacking disease resistance to improve the groundnut crop in sub-Saharan Africa.

Development of a molecular-based detection tool for sweet potato leaf curl viruses and determination of their incidence levels in Tanzania

Sweet potato (Ipomoea batatas L.) is an important food security crop in sub-Saharan Africa, where its production is constrained by devastating diseases; including those caused by sweet potato leaf curl viruses (SPLCVs; Begomovirus; Geminiviridae). The objective of this study was to develop a molecular-based diagnostic detection tool for SPLCVs, as well as to generate information on their geographical distribution and incidence in Tanzania. A comprehensive survey of SPLCVs was done in all major sweet potato growing areas in Tanzania. Incidences of SPLCVs and their causative diseases were determined visually and by polymerase chain reaction (PCR), using primers designed, optimised and validated. DNA was extracted from 4166 sweet potato leaf samples and detection of SPLCVs was done. Visual incidence of disease symptoms ranged from 0 to 100%; while PCR-based incidence of SPLCVs ranged from 0 to 60%. The highest mean PCR-based incidence of SPLCVs was 32%. SPLCVs occurred in all sweet potato growing areas. There was a negative correlation between the visually assessed incidence of disease symptoms and PCR-based incidence of SPCLVs (r = -0.122 and R2 = 0.012). A weak positive correlation between altitude and PCR-based incidence of SPLCVs was also found. In ten-fold serially diluted sweet potato DNA samples, using our new primer pair d1-SPLCVF/d1-SPLCVR, the detection limit of SPLCVs was at the dilution of 10-3. The youngest fully expanded leaf of the sweet potato plant was the best for PCR detection of SPLCVs. These findings will be useful for strategic deployment of planting material and conducting sweet potato breeding experiments for resistance against SPLCVs.&#x0D;

Diversity and spatial distribution of sorghum on farmers’ fields in Uganda

Sorghum (Sorghum bicolor (L.) Moench) is a food security crop in sub-Saharan Africa, which requires constant breeding in response to changes in the fragility of agricultural production environments. Hence, understanding and tenacious use of genetic variation in sorghum germplasm is essential for improving the crop to cope with environmental changes. The objective of this study was to determine the levels of diversity and spatial distribution of sorghum on farmers’ fields in major sorghum growing regions in Uganda. A survey involving 180 fields was conducted in three districts, namely Agago and Apac (northern) and Serere (eastern) all in Uganda. Diversity was measured in terms of number of accessions per field, the Shannon-Weaver and Simpson diversity indices. In order to assess spatial distribution of sorghum diversity on the fields, correlation analysis was carried out between diversity and geographical distances between fields. Overall, Agago district had the highest number of accessions per unit area (4.47); while Apac had the lowest (1.62). The spatial distribution of sorghum diversity showed a positive correlation (r = 0.381 for Agago, 0.124 for Apac and 0.081 for Serere), between geographical distances and diversity across the three districts; implying that fields close together share similar sorghum varieties. This can be due to sharing seeds between farmers within a given location. Sorghum diversity was spatially distributed in the fields, with fields close to each other shared most sorghum types. The levels of sorghum diversity on fields were highest in Agago and lowest in Apac district. The existing on-farm sorghum diversity offers the opportunity for improving sorghum through natural breeding against biotic and abiotic stresses.&#x0D;

Biological control interventions and botanical pesticides for insect pests of crops in sub-Saharan Africa: A mapping review

Agricultural productivity can be increased sustainably in sub-Saharan Africa (SSA) by reducing crop losses due to insect pest damage. As an alternative to environmentally-damaging chemical pesticides, biological control interventions and botanical pesticides show potential to achieve both high yields and profits. However, synthesized information of their performance and understanding of their adoption among smallholder farmers is limited. Here, 173 studies of biological control interventions and botanical pesticides of insect pests for 35 crops from 20 sub-Saharan countries from 2005 to 2021 were systematically reviewed. Drawing on published datasets, we found that cereals, particularly maize, were the most studied crop (59%). Research on botanical pesticides constituted 32% of the studies, followed by augmentation/introduction biocontrol (29%), and push-pull (21%). Studies evaluating the technical performance of biocontrol interventions dominated (73%), with a regional clustering of push-pull studies in Kenya. Few studies investigated each intervention on each crop type, across different farming contexts and scales, highlighting an urgent need for landscape-scale studies to elucidate land-use impacts on biocontrol effectiveness. Limited evidence also exists on the synergistic effects of biocontrol on multiple ecosystem services and on non-target/beneficial organisms. We found an absence of interdisciplinary studies that addressed the wider indirect benefits of not using chemical pesticides, the social-economic outcomes, and barriers to adoption by farmers, which we argue are necessary to identify pathways to greater adoption and to support policy advocacy of biocontrol interventions in SSA.

Incorporating male sterility increases hybrid maize yield in low input African farming systems

Maize is a staple crop in sub-Saharan Africa, but yields remain sub-optimal. Improved breeding and seed systems are vital to increase productivity. We describe a hybrid seed production technology that will benefit seed companies and farmers. This technology improves efficiency and integrity of seed production by removing the need for detasseling. The resulting hybrids segregate 1:1 for pollen production, conserving resources for grain production and conferring a 200 kg ha−1 benefit across a range of yield levels. This represents a 10% increase for farmers operating at national average yield levels in sub-Saharan Africa. The yield benefit provided by fifty-percent non-pollen producing hybrids is the first example of a single gene technology in maize conferring a yield increase of this magnitude under low-input smallholder farmer conditions and across an array of hybrid backgrounds. Benefits to seed companies will provide incentives to improve smallholder farmer access to higher quality seed. Demonstrated farmer preference for these hybrids will help drive their adoption.

Nutritional management and maize variety combination effectively control Striga asiatica in southern Africa

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−1) to soil infected with Striga, significantly (p < 0.05) reduced Striga counts and haustorial root attachments in all varieties with CV4 and R201 supporting lowest numbers. P also significantly (p < 0.05) improved plant height, chlorophyll content, leaf, cob, total biomasses and grain yield across all maize genotypes. Cultivar CV4 produced the highest grain yield under Striga attack. Furthermore, cultivars CV4 and CV1 had significantly (p < 0.05) lowest Striga seed maximum germination distance and percentages at zero P. Application of P reduced Striga germination, attachments and emergence in all varieties and increased tolerance of maize varieties.

Rainwater harvesting and Leucaena leucocephala biomass rates effects on soil moisture, water use efficiency and Sorghum bicolor [(L.) Moench] productivity in a semi-arid area in Zimbabwe.

Sorghum is one of the major staple crops in Sub Saharan Africa but its production is mainly limited by moisture stress, frequent droughts and soil infertility, especially in the smallholder farming systems. This raises the need to develop climate smart options to improve sorghum production. The objective was to assess the effects of rainwater harvesting and use of different Leucaena leucocephala biomass rates on soil moisture content, rainwater use efficiency, and stover and grain yields in two sorghum varieties (Macia and SV1). The experiment was laid as a randomized complete block design in split-split plot arrangement from 2017/2018 to 2019/2020 season. The results show that tied contour (TC) and infiltration pits (IPs) significantly (P < 0.05) increased soil moisture content than standard contour (SC). Soil moisture content increased gradually with the increase in soil depth (20-40 cm > 0-20 cm), with 2018/2019 season having the maximum soil moisture content. Soil moisture content also increased with the increase in application rates of Leucaena biomass. Grain and stover yields were significantly (P < 0.05) increased by all Leucaena biomass application rates with higher yield observed in 2018/2019 season. SC had significantly lower grain and stover yields at all Leucaena biomass application rates. TC and IPs had comparable rainwater use efficiency compared to SC. Rainwater use efficiency increased with application rates of Leucaena biomass across all seasons and varieties. TC and IPs are better adaptive mechanisms against drought spells in semi-arid areas and can be combined with 10 t ha-1 of Leucaena biomass due to better yield increments realized. © 2022 Society of Chemical Industry.