Department of Crop Science

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    Yam Nematodes as Production Constraints in Ghana: A Socio-Economic Perspective.
    (MDPI, 2025-01-10) Whedie et al.
    Abstract: Yam (Dioscorea spp.) has been a prominent food and cash crop for most farmers in the yam production areas of Ghana, with the sales of yam in both domestic and international markets contributing significantly to the economy of the country. However, yam production by smallholder farmers is constrained by several challenges, including postharvest loss resulting from yam nematodes. This study conducted field surveys across seven districts across Ghana to collect data from randomly selected 150 yam farmers to investigate the status of nematode infestation, management practices and other socio-economic factors contributing to yam production in the country. The most common farm size for yam production from 2019 to 2022 was between 0.4 and 0.8 hectares. The majority of the farmers (56%) have been farming for over 15 years, with 6–10 years of experience in yam production, and preferred to use their own planting materials every year. Although most farmers (97.99%) experienced pests and diseases, most of them (77.33%) had no knowledge about nematode infestations in their farm causing damage to the tubers. Although yam farmers experienced yield losses, farmers were unable to manage nematode infestations in their farms. Twelve (12) genera of nematodes were identified in soils of yam rhizosphere across the seven districts. Tylenchus spp. (35.5%) and Scutellonema spp. (92.8%) were the most abundant nematode in soil samples and tuber peels, respectively while the second highest nematode in tuber peels was Meloidogyne spp. (4.0%). The presence of these parasitic nematodes in yam farms across Ghana suggests serious threats to the growth and yield of yams, although their presence is either not known or is usually neglected. Our result also confirmed the correlation between farmer storage practices and the management of nematodes, suggesting some storage practices such as barns may be effective in controlling nematodes. On the other hand, we find no association between pest occurrence in the field and nematode management. The lack of an association could be an indication that pest management in the field and nematode management in storage are separate activities and this underlines the importance of providing tailored postharvest training for smallholder farmers in effectively managing nematodes. It was therefore necessary to undertake this study and establish knowledge on the species as well as their prevalence in the farms across Ghana, contributing towards enhanced farmers’ understanding on nematode management and effective storage of yams to prevent losses caused by nematode infestation.
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    Optimization of cassava (Manihot esculenta Crantz) grafting technique to enhance its adoption in cassava cultivation
    (MethodsX, 2024) Opoku-Agyemang, F.; Amissah, J.N.; Owusu-Nketia, S.; Ofori, P.A.; Notaguchi, M.
    Grafting techniques have been successfully adopted to improve resistance to biotic and abiotic stresses, increase yields, fruit quality and study systemic signaling in plants. This technique has not been fully explored in cassava and there is currently no standardized grafting method for this species published especially in Africa. This is the first report on cassava grafting protocol in Africa with valuable advantages including utilizing a cost-effective and environmentally friendly wooden healing chamber. In this study, we describe an optimized cleft grafting protocol for cas sava utilizing a wooden healing chamber and outline the step-by-step procedure with optimum conditions to generate a high grafting success rate. Using a top wedge grafting technique with high reproducibility and success rates, we developed a straightforward and robust grafting protocol for cassava (M. esculenta) cultivars. Grafting success was recorded and this protocol produced a high grafting success of 90 % and its reproducibility makes it suitable for mass production thereby addressing the need for efficient cassava propagation. This grafting protocol requires less special ized equipment and expertise making it more accessible to farmers and researchers with limited resources to promote the use of grafting for cassava growth, yield improvement and advanced studies such as systemic long-distance signaling in plants. • Optimization of cleft grafting method obtains a high success grafting rate of cassava. • A wooden healing chamber provides a controlled environment for graft healing. • Promoting cassava grafting; a priority to produce new cultivars and explore breeding research prospects.
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    The African Plant Breeders of Tomorrow
    (African Journal of Food, Agriculture, Nutrition and Development, 2019) Mumm, R.H.; Danquah, E.Y.
    Advances in agricultural productivity in Africa have lagged, as reflected by the fact that varieties have often popular with farmers for more than 14 years (Walker et al. 2015). The distribution and adoption of improved crop varieties has been stymied in part by an insufficient number of plant breeders on the continent. Would-be plant breeders often chose to pursue MS- and PhD-degree programs in the USA or Europe, and more than half of these did not return to Africa to practice their profession once graduated (Ali et al. 2007). The University of Ghana determined to change this by establishing the West Africa Centre for Crop Improvement (WACCI) in 2007, in partnership with Cornell University, to offer quality education and training in Genetics and Plant Breeding to African students. Supported by the Alliance for a Green Revolution in Africa (AGRA) as part of a strategy to launch a Green Revolution in Africa, WACCI aimed to create a sizeable, innovative workforce to increase agricultural productivity and ensure food security, especially for the people of west and central Africa. Professor Eric Yirenkyi Danquah, a visionary leader, was appointed to establish and direct WACCI. He determined to create a pathway from BS to MS to PhD in plant breeding at the University of Ghana to serve students from both English-speaking and French-speaking countries and to attract both men and women into the program, to establish WACCI as a leading institution for plant breeding education on the global stage.
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    Reorienting research investments toward under-researched crops for sustainable food systems
    (Food and Energy Security, 2024) Munialo, S.; Siddique, K.H.M.; Amissah, J.N.; et al.
    The dominance of a few staple crops (maize, rice, and wheat) in most agricultural systems hampers the application of interventions to improve food security and nu trition. Research and development attention has focused on improving the pro duction and utilization of these crops, leaving other crops under-researched and underutilized. Subsequently, there have been high malnutrition rates due to poor diet diversity, yet there are “opportunity crops” that remain under researched. The opportunity crops can unlock solutions to food insecurity, malnutrition, a lack of biodiversity, and indeed poor climate adaptation. The study explored diversifica tion in agricultural systems to analyze whether reorientation of research invest ment to include under-researched crops can increase nutrient gain and enhance dietary diversity. Research outputs benchmarked as the number of publications from three leading African universities, Nairobi, Pretoria, and Ghana, were related to crop diversity and nutrition of crops in five clusters: cereals, vegetables, leg umes, roots and tubers, and nuts. The findings show that maize was the predomi nantly researched crop across the three institutions. Low research outputs were observed for pearl millet, finger millet, and yam across the three institutions: ama ranth and nightshade (Pretoria), sweet potatoes (Pretoria and Ghana), Marama bean (Nairobi), and soya bean (Nairobi and Ghana). There was nutrient gain across all five clusters, particularly from under-researched indigenous crops such as finger millet, amaranth, nightshade, yam, sweet potatoes, Marama bean, and soybean. Nutrient gain was contributed more by cereals and root and tuber crops from Pretoria, vegetables and nuts (Ghana), as well as legumes (Nairobi). The find ings demonstrate that incorporating research on the least researched crops with successful integration of other research and development initiatives (policy and dissemination) can increase nutrition and improve dietary diversity. The nutrient gain will positively affect food security and nutrition, contributing to the achieve ment of Africa Agenda 2063, the United Nation's Sustainable Development Goals,and reducing food imports. The findings can inform research investment and decision across different institutions within the African continent. Research in vestment targeting crops such as finger millet, amaranthus, sweet potatoes, soya beans, and cashew nuts is needed considering the nutritional contribution, cli mate change adaptability, market potential, and biodiversity contribution. Further analysis should explore production, socio-economic (marketability and income generation), and environmental gains (adaptive ability to climate change) for spe cific crops. The development of frameworks to guide the analysis of the nature and scope of factors affecting the contribution of these crops to food security and nutri tion, as well as research on specific crops considering geographic distribution and institutional involvement, is also needed.
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    Evaluation of Preplant Seed Protectants for the Management of Root-Knot Nematode of Okra in Ghana
    (International Journal of Agronomy, 2024) Baah, P.; . Nyaku, S.T.; Agamah, B.; Tongoona, P.B.
    Root-knot nematode (Meloidogyne incognita) poses a signifcant threat to okra production, resulting in substantial yield losses. Te objectives of this study were to assess the impact of biological seed protectants on the growth and establishment of okra plants and nematode population reduction in soil. Okra seeds were coated with 40% sesame oil, 50% neem oil, 100% citrus oil, velum at 3.8 ml/7l of water, and a control (sterilized distilled water) at diferent time intervals of 30 min, 60 min, 90 min, and 120 min to determine the germination percentages and vigor. Te experimental setup was laid out in a completely randomized design (CRD), with three replications, utilizing a Jacobson table for the germination test. Te laboratory results demonstrated signifcant diferences (P < 0.05) in germination percentage and vigor index across the diferent time intervals. Neem oil, citrus oil, and velum exhibited higher germination percentages and vigor indices at all time intervals. Notably, 30-minute time interval proved to be efcient with 100% citrus oil producing 80.33% germination and 965 vigor index and 50% neem oil producing 75% germination and 994 vigor index. Field evaluations revealed citrus at 100% concentrations as seed coating (T5) and neem at 50% concentrations as seed coating (T3), with the highest nematode reductions (90.1% and 90.4%) and least reproductive factors (RFs) of 0.05 and 0.04, respectively, at the Atomic farms. Te study has revealed that treating okra seeds with 100% citrus oil and 50% neem oil has the efcacy of reducing nematode reproduction in soil, while enhancing germination and seedling vigor, together with an improvement in growth and yield. Sesame oil has a negative infuence on seed germination and vigor and is therefore not recommended as a preplant protectant
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    Response of pepper (Capsicum annuum L.) to preemergence application of Oxadiargyl and pendimethalin
    (Journal of Agriculture and Food Research, 2023) Nketiah, V.; Ofosu–Anim, J.; Cornelius, E.W.; Kotey, D.A.; Tetteh, R.
    Two field experiments were conducted in two agro-ecological zones of Ghana (Forest and Coastal Savannah) to assess the efficacy of preemergence herbicides Oxadiargyl and Pendimethalin on weed incidence, growth and yield of pepper. The experiment was factorial arranged in a randomized complete block design. The treatments were Oxadiargyl at 0.4, 0.5, 0.6 L/ha, Pendimethalin at 1.5, 2.0, 2.5 L/ha and hand weeding at intervals of 3, 6 and 9 weeks as control. Data was collected on weed type and abundance, number of days to weed emergence, type of re-emerging weeds and percentage weed cover. Data on plant height, number of branches per plant, yield and yield components of pepper plants were also collected. Results indicated that application of Pendimethalin led to a significantly (p < 0.05) longer number of days to weed emergence as compared to the application of Oxadiargyl which also delayed weed emergence significantly longer than hand weeding. Plant height was not affected by weed control method. The yield of pepper plants was significantly higher in plots where Pendime thalin (2.0 L/ha) was applied. Generally, the yield components of pepper plants have been positively affected by weed control treatments. However, application of Pendimethalin at 2.0 L/ha resulted in better weed control
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    Influence of β-Ionone in the Phytotoxicity of the Rhizome of Iris pallida Lam
    (Plants, 2024) Sothearith, Y.; Appiah, K.S.; Sophea, C.; et al.
    Iris pallida Lam., also known as Sweetie Iris, is a perennial ornamental and medicinal plant that produces a wide range of secondary metabolites. The Sweetie Iris was recently reported to have high allelopathic properties with the potential to be explored in sustainable weed management. This study aimed to identify and evaluate the contributions of compounds involved in the inhibitory effects of the rhizome of Sweetie Iris. High-performance liquid chromatography (HPLC) analysis was used to determine the content of β-ionone in the rhizome of Sweetie Iris. The phytotoxicity of β-ionone was evaluated on lettuce (Lactuca sativa L.) and other test plants. The content of β-ionone The crude extract of Sweetie Iris rhizome was found to be 20.0 mg g1 by HPLC analysis. The phytotoxicity bioassay showed that β-ionone had strong inhibitory activity on the growth of lettuce (Lactuca sativa L.) and the other test plants, including Taraxacum officinale, Stellaria media, Eleusine indica, Amaranthus hybridus, Vicia villosa, and Brassica napus. At a concentration of 23.0 µg mL−1, , β-ionone inhibited the growth of all test plant species treated. Therefore, β-ionone is an active compound among the other allelopathic substances contained in the rhizome of Sweetie Iris.
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    Mechanisms and modelling approaches for excessive rainfall stress on cereals: Waterlogging, submergence, lodging, pests and diseases
    (Agricultural and Forest Meteorology, 2024) Kim, Y-UK.; Webber, H.; Adiku, S.G.K.
    As the intensity and frequency of extreme weather events are projected to increase under climate change, assessing their impact on cropping systems and exploring feasible adaptation options is increasingly critical. Process-based crop models (PBCMs), which are widely used in climate change impact assessments, have improved in simulating the impacts of major extreme weather events such as heatwaves and droughts but still fail to reproduce low crop yields under wet conditions. Here, we provide an overview of yield-loss mechanisms of excessive rainfall in cereals (i.e., waterlogging, submergence, lodging, pests and diseases) and associated modelling approaches with the aim of guiding PBCM improvements. Some PBCMs simulate waterlogging and ponding environments, but few capture aeration stresses on crop growth. Lodging is often neglected by PBCMs; however, some stand-alone mechanistic lodging models exist, which can potentially be incorporated into PBCMs. Some frameworks link process-based epidemic and crop models with consideration of different damage mech anisms. However, the lack of data to calibrate and evaluate these model functions limit the use of such frame works. In order to generate data for model improvement and close knowledge gaps, targeted experiments on damage mechanisms of waterlogging, submergence, pests and diseases are required. However, consideration of all damage mechanisms in PBCM may result in excessively complex models with a large number of parameters, increasing model uncertainty. Modular frameworks could assist in selecting necessary mechanisms and lead to appropriate model structures and complexity that fit a specific research question. Lastly, there are potential synergies between PBCMs, statistical models, and remotely sensed data that could improve the prediction ac curacy and understanding of current PBCMs’ shortcoming
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    Sustainable P-enriched biochar-compost production: harnessing the prospects of maize stover and groundnut husk in Ghana’s Guinea Savanna
    (Frontier in Environment Science, 2023) Fianko, D.A.; Nartey, E.K.; Abekoe, M.K.; et al.
    Farmers in resource-poor areas of the Guinea Savanna zone of Ghana often face declining soil fertility due to the continuous removal of nutrient-rich harvested produce from their fields. This study focuses on the Lawra Municipality in the Guinea Savanna zone of Ghana, where low soil fertility, specifically, limits phosphorus (P) bioavailability and hinders crop production. The objective of this research is to formulate P-enhanced biochar-compost from maize stover (MS) and groundnut husk, which abound in the area, to close the nutrient loop. MS was co-composted with groundnut husk biochar at varying rates of 0, 10, 20, 30, and 40% by volume. To facilitate decomposition using the windrow system, the composting heaps were inoculated with decomposing cow dung, and the moisture content was kept at 60% throughout the monitoring period. The addition of biochar shortened the lag phase of composting. However, rates above 20% resulted in reduced degradation of MS. Biochar incorporation enriched the available phosphorus content in the final compost from 286.7 mg kg−1 in the non-biochar-compost to 320, 370, 546, and 840.0 mg kg−1 in the 10, 20, 30, and 40% biochar-compost, respectively
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    The use of Beauveria bassiana for the control of the larger grain borer, Prostephanus truncatus, in stored maize: Semi-field trials in Ghana
    (Fungal Biology xxx, 2023) Luke, B.; Acheampong, M.A.; Rangel, D.E.N.; et al.
    Laboratory research in Ghana demonstrated the effectiveness of an isolate of Beauveria bassiana (IMI 389521) from the United Kingdom against the larger grain borer Prostephanus truncatus (Horn) (Cole optera: Bostrichidae), a major pest of stored maize. The minimum effective concentration, following artificial infestation trials on maize, was between 109 and 1010 cfu/kg maize. Before moving out to village level control, a major requirement was to determine if the product could effect control in artificially infested maize held under real environmental conditions in several locations in Ghana. Therefore, this study investigated the efficacy of formulated conidia of B. bassiana, IMI 389521, at two concentrations (1 109 and 3.16 109 cfu/kg maize) to control P. truncatus on stored maize kernels under semi-field conditions in Ghana. Maize (‘Obatanpa’ cultivar) kernels were treated with the formulated B. bassiana product and stored in polypropylene woven bags in cribs in Southern Ghana. After 24 h, one hundred adults of P. truncatus were placed into each bag containing the treated maize. Mortality and the percent of weight loss of kernels were assessed every two weeks for three months. The semi-field trials revealed the possibility of successfully controlling adult P. truncatus on maize kernels treated with B. bassiana at 3.16 109 cfu/kg maize. However, due to the minimal protection of kernels after four weeks, re-treating maize kernels after this period is recommended to ensure maximum protection during prolonged storage.