Search

Identification of clones with promising growth and yield characteristics remains imperative for cocoa improvement in Ghana. This study assessed the relationship between selected trees from seed origin and their derived clones as a strategy to identify superior cocoa clones. Two experiments consisting of 40 progeny families, and 160 derived clones (plus 20 parents) respectively, were conducted at the Cocoa Research Institute of Ghana, New Tafo-Akim, from 2008 to 2022 to assess the genetic association between the two populations. Agronomic traits measured included stem diameter (vigour) at the juvenile and reproductive phases of growth, as well as bean yield and its components. Significant genetic variation was estimated among the ortets and their ramets for all measured traits. Relatively wide variation and superior performance were observed among the ramets compared with the ortets for all measured traits suggesting the achievement of substantial genetic improvement in the ramets to warrant selection progress. Additionally, the results revealed significant regression co-efficients and correlation patterns, along with high realized heritability values between the ortets and their ramets for bean yield and pod value indicating that high yielding clones with desirable pod values could be identified by relying on the genetic relationship between the progeny families and their derived clones. The high yielding ramets, CRG 0148/418, CRG 0121/106, CRG 0149/210, and CRG 0150/114 identified are therefore, invaluable for utilization in cocoa enhancement programmes across the globe. [ABSTRACT FROM AUTHOR]

The cacao swollen shoot disease (CSSD) caused by a complex of badnavirus species presents a major challenge for cacao production in West Africa, especially Ghana and Côte d'Ivoire. In this study, CSSD species detection efficiency, diversity, and geographic distribution patterns in cacao plantations in Ghana and Côte d'Ivoire were investigated through field surveillance, PCR detection assays, sequencing of positive amplicons, and phylogeographic clustering. Cumulatively, the detection efficiency of the tested CSSD primer sets that were targeting the movement protein domain of the virus ranged from 0.15% (CSSD-3 primer) to 66.91% (CSSD-1 primer) on all the symptomatic cacao leaf samples assessed. The identified CSSD species differed phylogenetically and overlapped in distribution, with the cacao swollen shoot Togo B virus (CSSTBV) (n = 588 sequences) being the most prevalent and widely distributed compared to the other CSSD species that were encountered in both countries. Geographically, the cacao swollen shoot CE virus (CSSCEV) species (n = 124 sequences) that was identified was largely restricted to the bordering regions of Ghana and Côte d'Ivoire. These results provide updated knowledge of the geographic distribution of the key CSSD species and their diagnostic efficiency and, thus, provide guidance in identifying locations for structured testing of cacao germplasm and optimal diagnostics for the predominant CSSD species in Ghana and Côte d'Ivoire. [ABSTRACT FROM AUTHOR]

Bi-parental hybrids (BPHs) are recommended cocoa planting materials in Ghana and other West African countries. However, the inability to produce enough BPHs to meet farmers' demand makes it almost impossible to avoid open-pollinated families (OPF) in the supply chain. To study the effects of OPF on cocoa production, parentage analysis, vigor, and precocity of seven BPHs generated from a 4 × 2 North Carolina II (NC II) incomplete mating design were compared with eight OPFs. The 15 cocoa progenies together with two checks of Guiana (GU) origin were evaluated in a randomized complete block design with four replications across five contrasting locations for stem diameter increment (SDI) and number of pods per tree (NP). Parentage analyses at 75 single nucleotide polymorphism (SNP) loci of leave samples from the 17 progenies revealed that the BPHs were of the appropriate female and male parents, while the OPF had varying number of male parents. The pollination effect (bi-parental vs open-pollinated progenies) was not significantly different for both traits, but the BPH was relatively better and surpassed on average the OPF by 3.5% for SDI and 7.8% for NP. Crosses involving GU 144/ C, T63/967, and T65/238 as females in both the OPF and BPH showed predominantly higher performance than those with PA 7 and T79/501 for both traits. Among the promising female parents, GU 144/C is the only one that is not in the seed gardens and could be added to parental clones currently used in producing cocoa varieties in the seed garden. [ABSTRACT FROM AUTHOR]

The cacao swollen shoot virus disease (CSSVD) is among the most economically damaging diseases of cacao trees and accounts for almost 15–50% of harvest losses in Ghana. This virus is transmitted by several species of mealybugs (Pseudococcidae, Homoptera) when they feed on cacao plants. One of the mitigation strategies for CSSVD investigated at the Cocoa Research Institute of Ghana (CRIG) is the use of mild-strain cross-protection of cacao trees against the effects of severe strains. In this study, simple deterministic, delay, and stochastic ordinary differential equation-based models to describe the dynamic of the disease and spread of the virus are suggested. Model parameters are estimated using detailed empirical data from CRIG. The modeling outcomes demonstrate a remarkable resemblance between real and simulated dynamics. We have found that models with delay approximate the data better and this agrees with the knowledge that CSSVD epidemics develop slowly. Also, since there are large variations in the data, stochastic models lead to better results. We show that these models can be used to gain useful informative insights about the nature of disease spread. [ABSTRACT FROM AUTHOR]

Avocado is an important tree crop grown in the tropics, including Ghana. Avocados are primarily propagated by seed into trees, which grow to provide shade for young cocoa trees and, subsequently, food and income. Cultivation of this crop as a monocrop is limited in Ghana; hence, there is a considerable risk of losing desirable genetic materials. There has been an effort by scientists at the University of Ghana to collect and curate available avocado germplasm to preserve, multiply, and disseminate to growers. Nurserymen have been tasked with germplasm multiplication through grafting. Unfortunately, the outcome of this grafting practice has been inefficient due to the high incidence of grafting failure. This study assessed the effects of the grafting experiences of four nurserymen under no shade, traditional, and adjusted shade conditions on the graft success of two avocado scions (Fuerte and Hass). The results of this study indicated that the absence of shade led to complete graft failure. Nevertheless, modifying the conventional shade to 70% using shade net resulted in a 10-20% enhancement in graft success. The success of grafting was found to be more associated with the skill of the grafters rather than their age or years of grafting experience. In general, the low graft success rate in avocados was most probably attributed to variations in the skills of individual grafters. Grafter A achieved a graft success rate of 23-29% higher than the other grafters, suggesting variations in the skill levels employed. Significantly (p = 0.05), graft success was higher in the Fuerte cultivar than in the Hass cultivar. [ABSTRACT FROM AUTHOR]

In recent times, public concerns over the potential accumulation of heavy metals in agricultural soils and crops due to the excessive use of agrochemicals are increasing. This study was conducted in the Abuakwa North Municipality of Eastern Region, Ghana, to assess the status of heavy metals in cocoa soils and beans. Cocoa farms aged between 10 and 20 years and have received agrochemicals for at least 5 years were selected, and their adjacent forests were used as controls. Soil samples and cocoa pods were collected randomly and processed for laboratory analysis. The study discovered that across the sampling sites, heavy metal concentrations in soil were below permissible limits. However, contamination factor and geo-accumulation index results revealed that Tontro cocoa farms were considerably contaminated and moderately polluted respectively with Cu, probably due to long-term fungicide application. The concentrations of Fe (39.3–47.1 mg kg−1) and Zn (54.8–70.0 mg kg−1) in the cocoa beans across the communities were below the FAO/WHO's safe limit of 99.4 mg kg−1 and 73.0 mg kg−1 respectively. Lead (0.03–0.06 mg kg−1) and Cd (0.12–0.20 mg kg−1) concentrations were below the EU's maximum allowable level and Codex Alimentarius Commission's limit of 1.0 mg kg−1 respectively. However, bean Cu content in the Tontro farm (51.5 mg kg−1) was slightly above the EU's recommended maximum limit of 50.0 mg kg−1, possibly due to the continuous application of copper-based fungicides. The study showed that, overall, agrochemicals used for cocoa farming in Abuakwa North Municipality of Ghana did not cause serious harm to the soils and beans, since the mean metal concentrations were not alarming and guarantee public health safety. [ABSTRACT FROM AUTHOR]

The genus Auricularia contains mushrooms that are known for their edibility, ecological value; as decomposers and nutrient cycling. They also contain medically useful bioactive compounds; mostly polysaccharides with numerous pharmacological activities (antioxidant, anti-tumour, immunomodulatory, hypolipodemic, antidiabetic, anti-microbial, hepatoprotective etc.). They also contain nutritive compounds useful as nutraceuticals and are cultivated worldwide. We set out to update the collecting localities of Auricularia in Ghana with the view to extend the list of national occurrence. Field trips were made from August 2022 to July 2023 to Ashanti, Oti, Western North and Eastern Regions to record new localities of Auricularia. A desktop study collated the nutritional, medicinal and other bioactive compounds resident in the mushroom to assess potential for economic exploitation for health delivery. Morphological, anatomical and other characteristics of the fruiting bodies were determined to authenticate the samples obtained. Auricularia cornea was recorded for the first time on cocoa tree (Theobroma cacao) and cassava (Manihot esculenta L) sticks in Adansi North (Ashanti Region), Bowiri Amanfro and Bowiri Kyiriahi (Oti Region); Baakokrom, Sefwi Bekwai in the Bibiani-Anwhiaso Bekwai Municipality (Western North Region) as well as the Cocoa Research Institute of Ghana-New Tafo Akim (Eastern Region). There are seven Auricularia (A. auricula-judae, A. delicata, A. fuscosuccinea, A. hunteri, A. mesenterica, A. polytricha and A. cornea) in Ghana. The morphometric, anatomical and other physical characteristics agree with the reported data in the pertinent literature for A. cornea. The plethora of bioactive, nutritive and pharmacologically useful ingredients of the basidiomata makes the mushroom a potential source of economic value and gives credence to its exploitation for health delivery in our developing economy. [ABSTRACT FROM AUTHOR]

Cacao swollen shoot disease (CSSD) caused by complexes of cacao swollen shoot badnaviruses (family Caulimoviridae, genus Badnavirus) remains highly prevalent and devastating in West Africa. The disease continues to impact substantially on cacao yield loss, cacao tree mortality, and decline in foreign exchange income from cacao bean sales. Currently, the disease is estimated to have a prevalence rate of over 30% in Ghana, as assessed in the ongoing third country-wide surveillance program. Although achievements from past research interventions have greatly elucidated the etiology, biology, epidemiology, diagnostics, and management of the disease, there are some outstanding knowledge gaps. The role of these information gaps and their effect on CSSD epidemiology and prevalence remain unanswered. This paper summarizes existing scientific knowledge from past research achievements that have provided elucidation on CSSD epidemiology, management options, and guided future research. The discussion highlights the need for multidisciplinary research with modern tools and institutional collaborators to holistically bring clarity on knowledge gaps on pathogen biology, virus–host-–vector interactions, role of environmental and soil nutrient effects on CSSD severity, evolution pattern, role of alternative hosts on virus species diversity, vector population dynamics, and their overall impact on CSSD prevalence and integrated management in cacao plantations. [ABSTRACT FROM AUTHOR]

Allometric models which are used to describe the structure of trees in agroforestry systems are usually extrapolated from models developed for trees in forest ecosystems. This makes quantitative assessment of the functions of shade trees in agroforestry systems challenging since increased availability of light and space in these systems may induce structural differences from those growing under forest conditions. We addressed this issue by providing species-specific allometric information on the structural characteristics of associated shade trees on cocoa agroforestry systems and assessed if allometries conformed to theoretical predictions. At the plot level, stand and soil characteristics affecting tree structural characteristics were assessed. The study was conducted in cocoa agroforestry systems at Suhum, Ghana. The height-diameter at breast height (H-DBH) allometry had the best fits (R2 = 53–89%), followed by the crown area (CA)-DBH allometry (R2 = 27–87%) and then the CA-H allometry (R2 = 22–73%). In general, the scaling exponents of the CA-DBH, H-CA and H-DBH allometries conformed to the metabolic scaling theory (MST). However, both the CA-DBH and H-DBH allometries diverged from the geometric similarity model. Though forest tree species had similar crown areas as fruit trees, they were slenderer than fruit trees. Tree slenderness coefficients were positively correlated with soil P, Ca, Cu and the ratios (Ca + Mg):K, (Ca + Mg):(K + Na) and Ca:Mg, but not C:N while DBH and H were correlated with soil P and C:N ratio. Our results show that critical soil nutrients and their ratios affects shade tree structural attributes (e.g. slenderness and CA), which possibly restrict variations in species-specific allometries to a narrow range on cocoa systems. Furthermore, shade tree species richness and density are better predictors of relative canopy projection area (a proxy for shade intensity) than tree species diversity. In conclusion, the results have implications for shade tree species selection, monitoring of woody biomass and maintenance of biodiversity. [ABSTRACT FROM AUTHOR]

Developing and releasing cocoa varieties take several years of testing bi-parental crosses within the cocoa production belt. A critical phase in these testing schemes is multi-location evaluation under farmers' production conditions to elucidate the adaptation of promising varieties. The genotype and genotype- by- environment interaction (GEI) of 25 recently developed cocoa hybrids were assessed for establishment and precocity traits including stem diameter (SD) growth, percentage survival (%S), and number of pods per tree (NP). A randomized complete block design with four replications across five contrasting environments was used to evaluate the 25 hybrids together with two standard varieties. Variations due to genotype, environment, and GEI were highly significant (p < 0.001) for all the traits, with mean square of environment being the largest followed by the main effects and the GEI had the least. The mean performance of the hybrids ranged from 72.25% in PA7 × GEBP 303/B-M to 88% in PA7 × CRG 0543 for % S, 31.93 in T79/501 × CRG 0543 to 40.87 mm in GU 144/C × EQX 78 for SD and 2.41 in T79/501 × CRG 0543 to 4.14 in GU 144/C × EQX 78 for NP. The genotype main effects plus genotype × environment interaction (GGE) biplot analysis revealed that hybrid 2 (GU 144 × EQX 78) performed best for SD growth and NP, and 12 (T63/967 × CRG 0314) for %S in most of the locations including Akomadan that had more intense dry seasons over the period. They could be used in cocoa breeding programs that seek to improve production under marginal conditions. Tafo for NP and SD growth, and Akomadan for % S were identified as the most discriminating and representative locations and considered the ideal testing locations for establishment and precocity traits. For stability, hybrids 3 (GU 144 × MAN 15–2), 7 (PA7 × EQX 78) and 17 (T63/967 × T65/238) were the best for NP, % S and SD growth, respectively. They were significantly not different from the highest performing hybrids for all the traits and could be further monitored for yield production before recommended as planting materials in Ghana and beyond. [ABSTRACT FROM AUTHOR]

Cocoa fields in West Africa traditionally kept other tree species to provide shade for cocoa trees and obtain food and other products. Measuring other trees is paramount to monitoring environmental conditions in cocoa agroforests, but it has been difficult to apply at a large scale. This study presents the results of a rapid assessment method applied in Ghana, developed to measure non-cocoa tree characteristics based on easily observed parameters using sample surveys and mapping tools. We collected data from over 8700 cocoa farms and evaluated their biodiversity performance based on 6 indicators classified according to recommended thresholds to benefit biodiversity conditions. Our results show that species richness, shade cover, and potential for tree succession have the lowest proportions of fields with the recommended levels, with variations among regions and districts. The methodological procedure allowed us to identify priority areas and indicators falling behind desirable thresholds, which can inform training and management approaches regarding biodiversity-friendly practices in cocoa fields tailored to the needs of the farmers. The analysis procedure was developed with open-access automated routines, allowing for easy updates and replication to other areas, as well as for other commodities, enabling comparisons at different spatial scales and contributing to monitoring biodiversity over time. [ABSTRACT FROM AUTHOR]

Herbicide drift phytotoxicity is a problem in plantation crops due to application failures and unfavorable spray conditions. With the increased use of glyphosate in cacao plantations in Ghana, there are concerns about the effect on cacao growth and productivity from doses that potentially could be expected from drift. The aim of this study was to evaluate the physiological and growth response of young cacao plants exposed to glyphosate. Two field experiments were conducted in randomized blocks, with four replications. Glyphosate was applied at rates 0 to 720 g a.e. ha−1. Crop injury, shikimate accumulation, chlorophyll content, quantum efficiency of PSІІ (Fv/Fm), height, and stem diameter were evaluated. Increased glyphosate rates increased crop injury and shikimate accumulation and decreased chlorophyll content, quantum efficiency of PSІІ (Fv/Fm), and plant growth. Glyphosate rates 360 g a.e. ha−1 or higher resulted in >60% foliar injury and more than 10-fold increase in shikimate accumulation. Glyphosate reduced chlorophyll content to <10 and Fv/Fm to <0.35 at the highest rates. Glyphosate rates ≥180 g a.e. ha−1 reduced height and stem diameter of plants and caused reductions in stand count. Thus, cacao showed sensitivity to glyphosate, and severe injury impaired plant growth. [ABSTRACT FROM AUTHOR]

This paper evaluates the impact of the adoption of cocoa hand pollination (CHP) on the welfare of smallholder cocoa producers. Using data collected from 1200 cocoa farmers in Huni Valley and Kejebril districts of Ghana, we employed endogenous switching regression, propensity score matching and inverse probability weighted adjustment techniques to assess the impact. The two-step Cragg was used to examine the determinants of the decision and intensity of adoption. The results showed that education, marriage and farm size positively influenced both the decision and intensity of adoption of the CHP technique. The result further showed that the cost of labour for implementing the technology, age, education, family head, economic active members, age of the cocoa tree, off-farm work, credit access and farm size significantly determined the impact of adoption on smallholder cocoa producers' welfare. Additionally, there is a positive impact of CHP adoption on productivity, income and food security. Careful consideration should be given to these factors including collaborations between government and stakeholders in the cocoa industry through the regular sensitization and trainings for farmers on improved technologies as the CHP to increase productivity, household income and reduce food insecurity of smallholder cocoa farmers. [ABSTRACT FROM AUTHOR]

Mistletoes are parasitic flowering plants that attack plants like cocoa and kill branches distal to point of attachment. Consequently, cocoa farmers incorporate trees to provide shade to limit germination and establishment of Tapinanthus bangwensis mistletoe species, but without success. This study was conducted in South-Western Ghana to identify causal factors of mistletoe infestation using random forest (RF) regression. Spatial arrangement of cocoa trees was the most important factor explaining mistletoe density, which was significantly higher in farms planted at random than in rows. The results imply that planting cocoa trees in rows could mitigate mistletoe infestation of Ghana's cocoa agroforests. [ABSTRACT FROM AUTHOR]

Cocoa (Theobroma cacao) contributes significantly to Ghana's GDP and has made Ghana a recognized leader in the cocoa industry. However, there are myriad problems associated with Ghana's cocoa bean quality. One such problems stems from farmers paying less attention to the required postharvest activities (fermentation and drying) which contributes significantly to bean quality losses. This study investigated the effect of the duration of the traditional heap fermentation period and different drying methods: solar biomass hybrid dryer (SBHD) and traditional sun drying method (TSDM) on the bean quality of two cocoa varieties (hybrid cocoa and Amazonia). Quality attributes of cocoa beans such as pH, moisture content, fat content, crude protein, free fatty acids, phenolic contents, colour, and bean size were examined. The statgraphics statistical tool was used to analyse data and the least significant difference (LSD) was used to compare treatment means. Purple beans incidence was observed to be lower in hybrid with a value of 21.90% in the solar biomass hybrid dryer after 5 days of fermentation. Hybrid recorded the highest flavonoid value of 6069.74 mg QE/g DW in the traditional sun drying after 7 days of fermentation. Hybrid as well recorded the highest total phenolic value of 711.44 mg GAE/g DW in the solar biomass hybrid dryer under 5 days of fermentation. Results also indicated that using the solar biomass hybrid dryer resulted in the best moisture content removal and was very efficient compared with the traditional sun drying method in ensuring high-quality beans per international market standards. Cocoa beans dried under SBHD had the overall highest purity and were of better quality compared to those dried directly in the sun. There were no significant differences (p ≤ 0.24) in percentage purity among the cocoa samples studied. [ABSTRACT FROM AUTHOR]

Cocoa is an important crop for Ghana's economy, contributing 25% of Gross Domestic Product (GDP). The crop, however, is mainly cultivated on forest‐derived soils and is a major cause of land‐use change. Termites are an important biological component of tropical ecosystems providing numerous ecosystem services. Previous studies have indicated that termites are sensitive to forest disturbance and decrease in richness and abundance across land‐use intensification gradients, with consequences for the essential services that they provide. Native shade trees are often used to improve cocoa cultivation and may reduce the detrimental effects of land‐use change on some aspects of biodiversity. The aim of this study was therefore to explore how termites respond to land‐use change along a shade‐tree gradient in Kakum National Park and surrounding cocoa farms in Ghana (from forest at 80% tree cover to cocoa with no shade cover, to the extreme of cultivated arable crop land). It was predicted that termite richness and abundance would decrease with decreasing shade cover, and with increasing distance from the forest edge. Thirty‐four species from 29 genera were sampled, with Ancistrotermes crucifer being found in all the locations (47% of all encounters). Species richness and abundance differed marginally across the land‐use gradient, as well as the distance from the forest edge; however, species richness did not show any significance with distance. All the same, termite communities were robust to the disturbance. Our findings suggest that though site influenced species richness and abundance, cocoa trees can play a crucial role in maintaining biodiversity and environmental quality in an agricultural landscape by providing a habitat for forest species that are not found in pastures or farm fields. However, we caution that the relatively low forest baseline of existing forest diversity may inflate the value of cocoa land, with those forests no longer representing undisturbed natural habitats: this highlights that shifting baselines may need to be accounted for when interpreting findings in the Anthropocene. [ABSTRACT FROM AUTHOR]

The expansion of cocoa farms is a major driver of deforestation and emissions in Ghana's high forest zone. The Ghana Cocoa Forest Reducing Emissions from Deforestation and Forest Degradation Program (REDD+) was launched as the world's first commodity-based initiative to address emissions from deforestation caused by cocoa production and generate non-carbon benefits. Hotspot Intervention Areas were established to implement the Ghana Cocoa REDD+ program. This study combines Q-methodology with focus group discussions and interviews to assess stakeholder perceptions in the Juabuso-Bia cocoa landscape regarding the capacity of the Hotspot Intervention Area to facilitate the generation of governance and economic non-carbon benefits to sustain emission reductions. We found that introducing the Hotspot Intervention Area has re-centralized landscape governance, which, coupled with weak collaboration among stakeholders, has led to poor generation of non-carbon benefits. Furthermore, efforts to include women in the leadership structure of the Hotspot Intervention Area can be described as tokenism, and little has been done to improve land and tree tenure for vulnerable groups. This, combined with the low adoption of climate-smart cocoa practices, is likely to negatively affect the generation of economic non-carbon benefits. To overcome these challenges, we recommend reforming the Hotspot Intervention Area, bolstering community-level sensitization, improving access to decision-making spaces that will enhance the participation of women and minority groups in landscape governance, and improving farmers' tenure security through a registration scheme for land and trees. These recommendations can ensure the efficient generation of non-carbon benefits, which are key to the success of REDD+., (© 2024. The Author(s).)

Cocoa production is a leading driver of deforestation in the humid-tropics of West Africa. Reconciling climate change mitigation with livelihoods of farmers requires identification of production strategies to concurrently improve yield and profit while curtailing emissions of greenhouse gases (GHG). Using a 2021 plot-survey conducted in Ghana's Eastern region, we evaluated yields, GHG emissions, and value of production (VOP) (a profit indicator) across a typology representing the diversity of systems at plot-level. The typology was constructed by first stratifying plots according to shade levels and variety (hybrid vs. Amazonia) which resulted in three systems: Hybrid sun , hybrid variety under full-sun (little to no shade); Hybrid shade , hybrid and moderate shade (13–25 shade trees ha−1); and Amazonia, Amazonia under predominantly moderate shade. Next, factor analysis and clustering were used to group plots within each system according to cocoa yield, vegetation, management, and (local) climate conditions. Cluster analysis showed that fertiliser, weeding, pruning, hand pollination, cocoa tree density, and shade tree densities of differing heights were most influential for determination across systems. Hybrid shade had the highest net GHG removal rate at −6.8 ± 1.7 (± 95% CI) Mg CO 2 eq ha−1 yr−1: 48% and 127% higher (emissions more negative) respectively over Amazonia and Hybrid sun. Hybrid shade additionally had the highest average and least variable VOP among production systems at 669 ± 564 USD ha−1 yr−1, compared to Hybrid sun and Amazonia at 404 ± 442 and 213 ± 280 USD ha−1 yr−1 respectively. These results point to hybrid cocoa grown under moderate shade of 13–25 shade trees ha−1 as optimal for reconciling climate change mitigation with development in West African cocoa. • Study concurrently evaluates financial profits and GHG balances (N 2 O & CH 4 emissions, CO 2 removals) in West African cocoa. • Plot-level indicators are evaluated across a typology obtained from sample-stratification and clustering. • Hybrid cocoa under moderate shade (13-25 shade trees ha-1) had GHG removal increment of 127% over same variety without shade. • This system too had higher mean profits, thus best reconciling GHG mitigation and economic development for the region. [ABSTRACT FROM AUTHOR]

Côte d'Ivoire has increased cocoa prices by 50% in an effort to boost production, which has been affected by heavy rainfall and crop disease. Lower harvests from Africa's top cocoa producers have led to record-high prices for cocoa beans and chocolate. Ghana, another major cocoa producer, has secured a $200 million loan from the World Bank to rehabilitate plantations affected by the cocoa swollen shoot virus. The country has also taken measures to protect cocoa farms from the negative impacts of mining and smuggling. In Somalia, the Fisheries Ministry is threatening legal action against companies engaged in illegal fishing, while Kenya has received funding to support the production of indigenous vegetables and has also benefited from a temporary suspension of duty on cut flowers exported to the UK. Liberia is planning to develop 2000 hectares of lowland for rice production in an effort to increase domestic production and reduce reliance on imports. [Extracted from the article]

Soil organic carbon and main nutrient stocks play key roles in maintaining soil fertility and yields of agricultural crops including cocoa (Theobroma cacao). The amount of nutrients removed from the soil by the cocoa trees could be influenced by its physiological growth stage. A study was carried out to examine the changes in some soil physical and chemical properties with main nutrients availabilities under cocoa plantations at the Cocoa Research Institute in the Eastern Region of Ghana. Cocoa plantations of different ages (5, 10, 14, 18 and 23 years) were chosen based on similar land history. Soils at the study sites are classified as Xanthic Ferralsol (WRB series). On each plantation, one acre (0.4ha) plot was demarcated and divided into three blocks for soil sampling. Five core samples were taken at 0–15 cm depth per block, bulked together and subsample taken to the laboratory for analyses. Particle size analyses showed that all soils were of sandy loam texture. All soils were acidic with pH below 5.5, relatively low exchangeable K and Ca. Bulk density values varied with ages at highest in 18 years. Soils under 23 years old plantations had relatively lower bulk density than those of the other ages. Total nitrogen content under the 5, 10, and 18 years of cocoa plantations was below the critical values considered adequate for good cocoa growth. Soil carbon stock and available phosphorus content of the soil generally tend to increase with age of the cocoa plantations. These differential variations in the soil nutrients, namely, total N, available P, exchangeable K, Ca, and Mg among five different cocoa plantation ages suggest that total nitrogen, available P, and exchangeable Mg were higher than the critical levels for good cocoa growth under 23 years of cocoa plantations only, but exchangeable K and Ca were lower the critical levels for all ages of cocoa plantations. [ABSTRACT FROM AUTHOR]

Cocoa swollen shoot virus disease (CSSVD) is a major disease of cacao (Theobroma cacao L.) in Ghana and other West African countries that grow the crop. Attempts to develop resistant varieties since the discovery of the disease in 1936 have yielded little success. Recently, planting materials that are tolerant to the disease have been recommended for planting in areas with high CSSVD prevalence. However, the effect of CSSVD on yield component traits of most cacao clones including the tolerant varieties has not been well studied. To investigate the impact of CSSVD on these traits, reduction in bean weight (BW), number of beans per pod (NoBP) and dry bean yield (DBY) between symptomless and symptomatic trees, and disease incidence (DI) among 210 different cacao clones were evaluated. The clones were transplanted in June 2010 following a randomised complete block design with four replications consisting of three trees per clone per block. Response of the clones to CSSVD incidence had 180 of the genotypes having < 50% symptoms. Clones of Contanama, Iquitos, Marañon, Nanay and unknown derived from Upper Amazon parentage had less DI at the end of the study. The CSSVD effect (symptomless vs. symptomatic) was significant (p < 0.05) for DBY and NoBP, and the symptomless trees surpassed on average their symptomatic trees by 21.17% for DBY. Some of the best-performing clones identified under natural CSSVD infection were; COCA 3348/52 and GU 219/V among the underrepresented clones, B 36, ICS 40, NA 33 x IMC 67, T30/628, T60/887, T63/971, T 81/1879 and T 82/503 among those that combine high DBY with low yield reduction, and NA 124, T17/358, T35/78, T57/305, T63/971 x SCA 6, T65/239, T76/1835 and T82/2294 among those that combine high DBY with no disease incidence. Their inclusion in breeding programs that seek to develop resistant CSSVD varieties or deployment as planting materials in endemic areas to improve yield production in Ghana is recommended on the basis of the present observations. [ABSTRACT FROM AUTHOR]

Cocoa (Theobroma cacao L) is an understorey plant that is highly sensitive to drought, especially at the seedling stage. In Ghana, only 20% cocoa seedlings survive the dry spells within 24 months after transplanting. Potassium (K) is known to enhance the growth of plants root to increase water uptake under drought conditions. This study assessed the effect of different levels of K fertilizer in enhancing the drought recovery and survival of four cocoa genotypes grown in Ghana. A 3 × 3 factorial experiment in Randomized Complete Block Design was carried out at the FRNR farm, Kwame Nkrumah University of Science and Technology, Ghana in 2019/2020 and 2020/2021 cropping seasons. The treatments consisted of 0 g, 4 g and 6 g plant−1 of muriate of potash (60% K2O) and three cocoa varieties: Amaz15-15XEqx78 (V1); CRG8914XPA150 (V2) and PA7/808XPound10 (V3). The result showed that cocoa varieties applied with 4 g or 6 gK plant−1 produced higher (p <.05) belowground and aboveground biomass than the control. The K treated seedlings had about 77% survival rate than the control (43%) seedlings. Among the varieties, V2 had better drought recovery and survival rate (81%), followed by V3 (78%) and V1 (71%). In addition to the morphological characteristics, K enhanced the nitrogen content in cocoa seedlings during drought recovery and this correlated positively (R = 0.863) with survival rate. In conclusion, when farmers grow V2 and apply 4 gK plant−1 during drought, over 80% of the seedling will recovery and survive. This has implications for K fertility management, yield and the livelihood of smallholder (70%) cocoa farmers. [ABSTRACT FROM AUTHOR]

Agroecosystem strategies to enhance agrobiodiversity can curb many of the negative impacts associated with current food production systems. With rising interest in agrobiodiversity and agroforestry as farming interventions that confer ecological and socioeconomic benefits, understanding the intended pathways of interventions is important for successful agroecological transformations. Yet, the patterns of agrobiodiversity introduction and adoption remain elusive. Drawing upon social network research from the regions of Ghana where cocoa (Theobroma cacao) is grown, we synthesize the relationships between agroforestry interventions, information networks, and the adoption of diversified agroecosystems. We illustrate middle-level patterns from independent studies in three regions of Ghana and nearly 500 farmer interviews. Strong structural indicators at the network level are linked to agrobiodiversity; farmers in larger, less dense information networks with ties to external organizations tend to have higher reported and measured agrobiodiversity. Remarkably, these trends were found in environmentally and socio-culturally different contexts in Ghana. However, these trends do not, in all cases, scale to the community level. For example, we did not observe any clear relationship between the density of community networks and the measures of agrobiodiversity at the community scale. This may be on account of the type of agrobiodiversity measure applied (above-ground biomass) to assess community-level outcomes. Selection of environmental attributes with meaningful spillover effects, such as pest management, would more likely uncover nontrivial network effects at the collective level. Our findings support that both innovation and cooperation are indispensable for successful agrobiodiversity interventions, and that networks can operate to overcome negative outcomes of agrobiodiversity. Based on these studies, we conclude that agrobiodiversity adoption via interventions and established farmer-to-farmer networks may trigger the formation of other, observation-based networks that draw in socially distant actors. Our research strategy of ex-post qualitative comparisons allowed for in-depth insight into the complexities of information networks and agrobiodiversity adoption but also generated new hypotheses on the role of social networks in diversified farming systems. [ABSTRACT FROM AUTHOR]

Thread blight disease has recently been described as an emerging disease on cacao (Theobroma cacao) in Ghana. In Ghana, thread blight disease is caused by multiple species of the Marasmiaceae family: Marasmius tenuissimus, M. crinis-equi , M. palmivorus , and Marasmiellus scandens. Interestingly, two additional members of the Marasmiaceae ; Moniliophthora roreri (frosty pod rot) and Moniliophthora perniciosa (witches' broom disease), are major pathogens of cacao in the Western hemisphere. It is important to accurately characterize the genetic relationships among these economically important species in support of their disease management. We used data from Illumina NGS-based genome sequencing efforts to study the mitochondrial genomes (mitogenomes) of the four cacao thread blight associated pathogens from Ghana and compared them with published mitogenomes of Mon. roreri and Mon. perniciosa. There is a remarkable interspecies variation in mitogenome size within the six cacao-associated Marasmiaceae species, ranging from 43,121 to 109,103 bp. The differences in genome lengths are primarily due to the number and lengths of introns, differences in intergenic space, and differences in the size and numbers of unidentified ORFs (uORF). Among seven M. tenuissimus mitogenomes sequenced, there is variation in size and sequence pointing to divergent evolution patterns within the species. The intronic regions show a high degree of sequence variation compared to the conserved sequences of the 14 core genes. The intronic ORFs identified, regardless of species, encode GIY-YIG or LAGLIDADG domain-containing homing endonuclease genes. Phylogenetic relationships using the 14 core proteins largely mimic the phylogenetic relationships observed in gene order patterns, grouping M. tenuissimus with M. crinis-equi , and M. palmivorus with Mon. roreri and Mon. perniciosa , leaving Mar. scandens as an outlier. The results from this study provide evidence of independent expansion/contraction events and sequence diversification in each species and establish a foundation for further exploration of the evolutionary trajectory of the fungi in Marasmiaceae family. [ABSTRACT FROM AUTHOR]

Background: Postharvest treatments are crucial to the quality of cocoa finished products. This study aimed at investigating the effects of durations of fermentation and drying on the quality of cocoa (Theobroma cacao) beans during the rainy season. The study employed a 4 × 3 factorial with four fermentation durations of 5, 6, 7 and 8 days and three drying periods of 4, 5 and 6 days, resulting in a total of 12 treatment combinations, laid in a Completely Randomized Design with three replications. Bean quality data were collected on bean count/100 g, moisture content and cut test attributes including mouldy, slaty and purple, as well as percentage purity. Results: The study showed that the applied fermentation and drying periods single handedly resulted in moisture content higher than the recommended, coupling 8 days fermentation with 6 days drying period resulted in a moisture content of 5.6% which falls below the acceptable standard (7.5%) recommended. Number of beans/100 g increased with increasing fermentation and drying periods. Coupling any of the fermentation periods with 5 or 6 days drying duration resulted in mould content within the acceptable grade 1 limit (3%). Longer fermentation period coupled with any of the drying durations resulted in very encouraging and minimal values of purple, while coupling 6, 7 or 8 days fermentation period with 6 days drying resulted in slaty content within the grade 1 limit (3%). Conclusion: The overall effect of the treatments on the quality attributes from the cut test revealed that 8 days fermentation with the traditional leave heap method, coupled with 6 days sun drying during the rainy season, resulted in superior bean quality with a percentage purity of 98.00%. [ABSTRACT FROM AUTHOR]

The leaf of Theobroma cacao L. is used in traditional medicine in Ghana for the treatment of malaria, yet, with no scientific evidence of its antimalarial property in animals. It was, therefore, studied to validate the antimalarial property in Plasmodium berghei-infected mice. Infected mice were treated with an aqueous extract of T. cacao leaf at different doses of 100, 200, and 400 mg/kg daily for four days. Parasitaemia was determined before treatment and 24 hours following the last dose of extract. The % reduction in parasitaemia and ED50 and ED90 of the extract were determined. Body weight, rectal temperature, and daily mortality of mice were also recorded. The extract had ED50 and ED90 of 242.20 ± 29.38 and 351.00 ± 29.52 mg/kg/day, respectively. Percentage parasitaemia suppression was significant for all doses. The extract at the maximum dose of 400 mg/kg body weight had the highest % parasitaemia suppression of 79.19%; mean survival time of 24.00 ± 2.19 days and median survival of 23 days; body weight increase of 3.82 ± 0.59; and the lowest body temperature reduction of 0.79 ± 0.11°C. T. cacao leaf extract showed an antimalarial property in P. berghei-infected mice. This reinforces the justification for the use of the plant material in treating malaria in Ghana. [ABSTRACT FROM AUTHOR]

The success of sustainable Theobroma cacao (cocoa) production depends on the physical and chemical properties of the soils on which they are established but these are possibly moderated by the management approach that farmers adopt. We assessed and compared soil physico-chemical properties of young, mature and old organic and conventional cocoa agroforestry systems at two depths (0–15 and 15–30 cm) and evaluated the production of cocoa pods, banana and plantain in the two farm types. Cocoa farms under organic management had 20, 81, 88 and 323% higher stocks of soil organic carbon, P, Mn and Cu, respectively, compared to those under conventional management. Higher soil moisture content, electrical conductivity and pH were found on organic systems than the conventional farms. Annual cocoa pod production per tree was similar in both cocoa systems (Org. 10.1 ± 1.1 vs Con. 10.1 ± 0.6 pods per tree). The annual production of banana and plantain was higher on organic farms (186.3 ± 34.70 kg ha−1 yr−1) than conventional systems (31.6 ± 9.58 kg ha−1 yr−1). We concluded that organic management of cocoa agroforestry systems result in soils with the greater overall quality for cocoa production than conventional management and it increases the yield of co-products. Studies focusing on the impact of organic management on cocoa agroforestry systems at the landscape and regional scales are urgently needed to further deepen our understanding and support policy. [ABSTRACT FROM AUTHOR]

The cacao crop spread throughout the world from its center of origin in South America. However, one of its main diseases cacao swollen shoot disease (CSSD), which is caused by the complex of cacao-infecting badnaviruses, was first detected in Africa. Here we investigate the relationship between the genetic diversity of the viruses that cause CSSD and their geographical distribution, and the possible relationship between the genetic diversity of the virus and the symptoms they trigger. We also sought to determine the evolutionary models that could explain this relationship and evaluate the evolutionary history of the virus through ancestral state reconstructions and temporality analyses. A high mutation rate was observed along with a clear phylogenetic signal in the geographic distribution and in the symptoms associated with each viral species. The molecular clock provided new evidence on the emergence and speciation of cacao-infecting badnaviruses, suggesting a possible American origin of these viruses. • A high mutation rate was observed of the CSSV species. • Geographical region and Symptoms traits showed a clear phylogenetic signal. • In Africa, Ghana was found as the center of virus dispersal. • CSSV possibly originated from America. • The evolutionary history of CSSD together with cacao spread was reconstructed. [ABSTRACT FROM AUTHOR]

Sustainable cacao cultivation in Ghana has been seriously hampered by high seedling mortality due to the low soil fertility of lands used for the establishment of new cacao farms. Alleviating the low soil fertility to enhance sustainable cacao cultivation requires the use of fertilizers. A study was therefore conducted at the Cocoa Research Institute of Ghana to determine the effect of integrated application of poultry manure (PM) and sulphate of ammonia (SOA) fertilizers on survival, growth, and nutrient uptake by cacao seedlings under marginal field conditions. A randomized complete block design with four replications was used to evaluate the effects of six treatments. Traits assessed were percentage survival, height, trunk cross-sectional area (TCSA), and nutrient uptake. Results from the study showed no significant differences in soil N and K among the treatments. PM-amended plots had significantly higher soil P than nonamended control and SOA alone. Seedling survival rate ranged from 73.3 to 89.3% with a higher proportion of surviving plants in PM amended soils. The application of PM alone and its combination with SOA improved growth. Cacao trees of T4 (75% recommended dosage of SOA + PM) had the largest TCSA increment, which was significantly different from the other soil treatments. Leaf nutrient concentrations in cacao of T4 were higher than the other soil treatments. It was therefore concluded that T4 could be used during cacao establishment in marginal areas for improved plant survival and growth. [ABSTRACT FROM AUTHOR]

The inappropriate use of cacao clones either as female or male parents in seed gardens have been suggested as some of the reasons for the low yields of cacao hybrid varieties grown in West Africa. The concept of reciprocal effects in cacao crosses has not been well studied. To investigate the impact of maternal effect on growth and yield traits, reciprocal differences and combining abilities of recommended cacao parents in Ghana were evaluated. Six clones, comprising four important seed gardens clones used across West Africa and two clones previously used as standards in international breeding projects were crossed in a 6 × 6 complete diallel mating design to produce 30 F1 progenies. These progenies were tested in the field using a random block design with four blocks and elementary plots containing 20 plants. Growth and yield traits including stem cross-sectional area in juvenile stage, jorquette height, bean weight, number of beans per pod and bean yield were monitored over a 6-year period. Mean squares of general combining ability (GCA), specific combining ability (SCA) and reciprocal effects were significant for almost all the traits except jorquette height in SCA. This indicates that additive and non-additive gene effects are important in the inheritance of the traits. The presence of reciprocal differences for all traits suggests the influence of maternal effects in controlling the traits. Manual pollinations for commercial seed production should, therefore, follow established protocol and clones recommended as female and male parents used strictly as recommended. One of the standard clones, AMAZ15/15 had significant positive GCA effect for yield, and consistently produced progenies with high SCA values. It could be added to parental clones currently used in producing cacao varieties in the seed gardens in Ghana and other West African cacao growing countries. [ABSTRACT FROM AUTHOR]

Cocoa mirids are the most important insect pests of cocoa in West Africa. This study investigated the effect of environmental parameters that are modulated by overhead shade, that is, light intensity and temperature, on nutrient and phenolic concentrations in cocoa and their subsequent effect on mirid feeding. Eight‐month‐old cocoa seedlings were maintained for 50 days in two growth chambers set to day temperatures of 25 or 30°C. Each chamber had sections with different light intensities (541, 365 and 181 μmol m−2 s−1 photosynthetically active radiation [PAR]). For the field studies at Akim Tafo in Ghana, 8‐month‐old plants of three cocoa clones were subjected to shaded (PAR = 180 μmol m−2 s−1, between 11:00 a.m. and 12:00 p.m.) and unshaded (PAR = 1,767 μmol m−2 s−1, between 11:00 a.m. and 12:00 p.m.) treatments for 50 days after which nutrient measurements and mirid choice tests were carried out. No significant effect of environment was observed on the phenolic concentration of stems under controlled environment chamber conditions. However, in the field, the phenolic concentration of stems was significantly greater for unshaded compared with shaded plants (p =.04). Under controlled conditions, the leaf nitrogen concentration increased slightly with light intensity (p =.003). The same trend was seen in stems but only at 30°C. In the field, the impact of overhead shade on nitrogen varied between cocoa clones. The concentration of carbohydrates in both leaves and stems in the field was higher under unshaded conditions. When subjected to feeding tests, stems from unshaded cocoa had significantly more mirid feeding lesions (p =.003) after 24 hr exposure to mirids compared to shaded cocoa. Mirid feeding therefore appears not to be deterred by the higher phenolic levels but rather there was a preference for cocoa tissue grown under unshaded conditions. These findings highlight the need to consider the growing environment of cocoa clones when screening for varieties with resistance to mirids. [ABSTRACT FROM AUTHOR]

There is a paucity of information on nutrient stocks and distribution in the cocoa ecosystem for the management of production sites to improve its productivity. Apart, sites with long histories of cocoa production could differ in nutrient stocks and distribution relative to recent production regions. Therefore, some existing cocoa farms in Ghana were sampled on the basis of shade management (shaded and unshaded) and production site longevity (Eastern region > Western North region) to determine the nutrient stock and distributions in them. Over 93% of the total ecosystems' elementary nutrients were stored in the soil. Higher nutrient stocks occurred under shaded cocoa ecosystem. Nutrient element concentrations in cocoa tree biomasses followed the order: N > Ca > K > Mg > P > S > Al = Fe > Zn = Mn, and mostly concentrated in leaf > root = husk > branch > stem. On average, region as a main factor affected nutrient distributions. There was a sharp distinction between macronutrient and micronutrient accumulations in favour of Eastern region and Western North region, respectively. Therefore, the regional distinction with respect to macro- and micronutrients could be used as a guide to fertilizer recommendation for cocoa systems in the two regions. [ABSTRACT FROM AUTHOR]

Increasing soil acidity is one of the major factors limiting crop production in Ghana. Hence, identifying cocoa varieties that are well adapted to acidic soils and better extractors of important cocoa nutrients viz phosphorus (P) and potassium (K) is a suitable way to optimize the use of acidic soils to improve cocoa production. A 4 × 12 factorial in completely randomized design with four replications was used to evaluate 12 cocoa varieties grown in four acidic soils for the following traits: height, stem diameter, root length and volume, dry matter ,and nutrient uptake. No significant varietal and soil effects for height and stem diameter were observed. T60/887 × CRG 8914 and PA 150 × EQ 3338 produced higher dry matter yields. Varieties had significantly longer roots and bigger root volumes in Samreboi series than in the other soils. Dry matter yields were highest in PA 150 × EQ 3338 and T60/887 × CRG 8914 across the soils. Absolute amounts of nitrogen (N) and P uptake were highest in PA 150 × PA 88 across the four soils, while K was highest in SPD cross. Nutrients uptake across the varieties was in the order N > P > K in Nzima series and Samreboi series, and N > K > P in Wiawso series and Wacri series. The superiority of T60/887 × CRG 8914, PA 150 × EQ 3338, and PA 150 × PA 88 over the other varieties in terms of growth and nutrient uptake suggest they may be desirable for planting on acidic soils. [ABSTRACT FROM AUTHOR]

Black pod disease is caused by fungi of the species Phytophthora palmivora or Phytophthora megakarya. The disease causes darkening of affected areas of cocoa trees and/or fruits and leads to significant reduction in crop yields and decreases lifespan of the plant. This study presents a simple S1S2IT--type model with variable population size to assess the impact of fungicide treatment on the dynamics of the black pod disease. We do both theoretical studies and numerical simulations of the model. In particular, we analyze the existence of equilibrium points and their stability, simulate the model using data on reported black pod cases from Ghana. In addition, we perform sensitivity analysis of the basic reproduction number with respect to the model parameters. The results show that the top three parameters that govern the dynamics of the black pod disease are the treatment rate, transmission rate, and planting rate of new trees. [ABSTRACT FROM AUTHOR]

Cocoa agroforests are growing in importance with a view to meeting farmers' livelihood goals as well as ecological services. Following the recognition of cocoa agroforests as being useful for biodiversity conservation and farmers' livelihoods, there is a growing discourse on the fact that they may also be useful in climate change mitigation and biodiversity conservation. Several companies have expressed their willingness to be "deforestation" certified within the next two decades. In West and Central Africa, cocoa is part of the endeavour to contribute to the REDD+ mechanism. Besides producing cocoa beans, the additional expectations from cocoa agroforests (timber, NWFP, biodiversity conservation, carbon storage, etc...) depend on the trees associated with the cocoa plants. The manner in which associated trees are mixed in the system impacts on the cocoa plants and plants associated with cocoa trees within the agroforestry system thus impact on the products and services produced by these farming systems. Studies are being undertaken to identify the exact composition of these associated trees but very few deal with the manner in which these trees are structurally distributed—vertically and horizontally—within the cocoa agroforest. Understanding the way in which cocoa and non-cocoa trees are distributed within the system would be useful with a view to improving the farm system, thus meeting the needs of several stakeholders. The present study reviews the structure of cocoa orchards and agroforests in West and Central Africa (Cameroon, Nigeria, Ghana and Cote d'Ivoire) with a view to improving the products and services of cocoa landscapes. This review is centred around: (i) density of cocoa, (ii) density of associated plants, (iii) basal area or associated plants, (iv) stratification and space between components, and (v) the life cycle of cocoa plantation components. Densities of cocoa and associated plants in the field are not always those advised by extension services. The cocoa varieties play an important role in type and intensity of shade of the cocoa farms. In the context of multiple expectations placed on cocoa plantations, the unproductive cocoa trees in the farmer fields can be substituted by more vigorous ones or replaced by useful associated plants (Timber and NWFP). With the growing desire to reproduce some key attributes of local forests while responding to other economic and social needs associated with cocoa farms, the neighbouring/previous forest climax and its related basal area can be considered as a reasonable aim, when managing the cocoa agroforest. The life cycle of each of the plant components needs to be optimized in these spatial–temporal intensification considerations. In the prospect of vertical intensification, there is a need to give more attention to understorey management and the number of strata of the agroforest. In the context of sustainable management, a well-structured cocoa agroforest system needs to take landscape, local, national and global socio-economic and political issues into consideration. [ABSTRACT FROM AUTHOR]

Cacao swollen shoot disease (CSSD) caused by complexes of cacao swollen shoot badnaviruses (family Caulimoviridae , genus Badnavirus ) remains highly prevalent and devastating in West Africa. The disease continues to impact substantially on cacao yield loss, cacao tree mortality, and decline in foreign exchange income from cacao bean sales. Currently, the disease is estimated to have a prevalence rate of over 30% in Ghana, as assessed in the ongoing third country-wide surveillance program. Although achievements from past research interventions have greatly elucidated the etiology, biology, epidemiology, diagnostics, and management of the disease, there are some outstanding knowledge gaps. The role of these information gaps and their effect on CSSD epidemiology and prevalence remain unanswered. This paper summarizes existing scientific knowledge from past research achievements that have provided elucidation on CSSD epidemiology, management options, and guided future research. The discussion highlights the need for multidisciplinary research with modern tools and institutional collaborators to holistically bring clarity on knowledge gaps on pathogen biology, virus-host--vector interactions, role of environmental and soil nutrient effects on CSSD severity, evolution pattern, role of alternative hosts on virus species diversity, vector population dynamics, and their overall impact on CSSD prevalence and integrated management in cacao plantations.

Producer groups are influential in Ghana's cocoa value chain. They facilitate training, extension, education and inputs to their members. Still, there is no study on the impact of these producer groups on the technical efficiency and productivity of smallholder cocoa farmers. Using data from 217 and 199 members and non-members of cocoa producer groups, this study aimed to analyse producer groups' impact on smallholder farmers' technical efficiency and yield. The truncated normal distribution stochastic frontier model was adopted to estimate the farmers' technical efficiency. Since the model showed an issue of inefficiency among the farmers, we added socio-demographic and institutional variables to account for determinants of inefficiency. Finally, we adopted an endogenous treatment regression model to analyse producer groups' impact on the farmers' technical efficiency by accounting for observed and unobserved biases. The study results show that farm size, labour, and capital significantly positively impact the partial elasticity of production. Age, education, use of hybrid cocoa, involvement in off-farm jobs, extension access, and producer group membership significantly affect inefficiency. The results further show that producer group membership significantly impacts technical efficiency and yield from the endogenous treatment regression model. To deal with the issues of non-participating in the producer groups, the study recommends that producer groups should be made accessible to farmers. Policymakers can promote the formation and strengthening of producer groups, leading to improved productivity and technical efficiency among cocoa farmers. This approach empowers farmers, enhances their access to resources and knowledge, and enables them to collectively address common challenges, ultimately contributing to sustainable cocoa production and better livelihoods for cocoa farming communities., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2023 Donkor et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Terrestrial net primary productivity (NPP) is an important metric of ecosystem functioning; however, there are little empirical data on the NPP of human‐modified ecosystems, particularly smallholder, perennial crops like cocoa (Theobroma cacao), which are extensive across the tropics. Human‐appropriated NPP (HANPP) is a measure of the proportion of a natural system's NPP that has either been reduced through land‐use change or harvested directly and, previously, has been calculated to estimate the scale of the human impact on the biosphere. Additionally, human modification can create shifts in NPP allocation and decomposition, with concomitant impacts on the carbon cycle. This study presents the results of 3 years of intensive monitoring of forest and smallholder cocoa farms across disturbance, management intensity, distance from forest and farm age gradients. We measured among the highest reported NPP values in tropical forest, 17.57 ± 2.1 and 17.7 ± 1.6 Mg C ha−1 year−1 for intact and logged forest, respectively; however, the average NPP of cocoa farms was still higher, 18.8 ± 2.5 Mg C ha−1 year−1, which we found was driven by cocoa pod production. We found a dramatic shift in litterfall residence times, where cocoa leaves decomposed more slowly than forest leaves and shade tree litterfall decomposed considerably faster, indicating significant changes in rates of nutrient cycling. The average HANPP value for all cocoa farms was 2.1 ± 1.1 Mg C ha−1 year−1; however, depending on the density of shade trees, it ranged from −4.6 to 5.2 Mg C ha−1 year−1. Therefore, rather than being related to cocoa yield, HANPP was reduced by maintaining higher shade levels. Across our monitored farms, 18.9% of farm NPP was harvested (i.e., whole cocoa pods) and only 1.1% (i.e., cocoa beans) was removed from the system, suggesting that the scale of HANPP in smallholder cocoa agroforestry systems is relatively small. [ABSTRACT FROM AUTHOR]

• Cocoa is an important crop for millions of small holders, but low farm-level yields mean sustainable intensification is required urgently. • Modelling the response of cocoa yield to variation in rainfall would allow the response of cocoa to management to be estimated. • A time lag model (using a delayed differential equation) to simulate the effect of rainfall on cocoa seasonality was developed. • Parameterised using real cocoa yield data, the model outputs gave a good likeness to the observed on-farm yield response. • These results indicate high potential to develop this model to incorporate other climatic variables and farm management practices. Cocoa (Theobroma cacao) is an economically important crop grown by approximately six million of smallholder farmers throughout the tropics and sub-tropics. However, farm level yields are often very low, and sustainable intensification is urgently required. Assessing the impact of on-farm interventions of farm productivity and profitability requires an understanding of the contribution of inter-annual climate variability to cocoa yields. A Delayed Differential Equation model (DDE) was used to simulate the effect of rainfall on cocoa yields. A DDE model is an ordinary differential equation model that incorporates time lags, and is therefore able to incorporate the delay in yield response to rainfall due interactions with the cocoa flowering and the pod development processes. The DDE was constructed and based on regional rainfall and farm-level cocoa yield data from 96 farms across the main cocoa growing regions in Ghana. Model outputs indicate that a good likeness of seasonality in crop production was achieved. The potential to conduct a detailed parameterisation and extend this model to include other parameters such as agrochemical inputs and farm management practices are discussed. By further developing this model into a useful tool to predict and understand variability in cocoa yield, the sustainable intensification of small holder cocoa farming is supported. [ABSTRACT FROM AUTHOR]

Despite Ghana's large contribution to global cocoa production, average yields are low. Policymakers and practitioners are calling for implementation of a climate smart strategy by increasing yields and augmenting shade tree cover in cocoa systems. However, there have been few studies in West Africa on the relationship between shade and cocoa yield under field conditions. The objective of this study was to determine the effect of shade tree cover and other factors on on-farm cocoa yields over a four-year period. The study was conducted on 86 farm plots of 8–28 years' cocoa trees with varied canopy cover (CC) in Ashanti and Western regions of Ghana. A linear mixed model analysis showed that yields increased significantly with increased CC of shade trees, and indicated a doubling of yields when going from zero to approximately 30% crown cover. Fertilizer use gave a yield increase of 7%. Farms located in Western region had higher yields compared to Ashanti, and cocoa systems on short fallows had lower yields than farms cultivated on recent forest clearings and old fallows. Fungicide use, seed sources and land ownership had no significant effects on yield. We conclude that for a sustainable climate-smart cocoa agenda, promotion of shade trees is key. [ABSTRACT FROM AUTHOR]

Cocoa (Theobroma cacao L.) root systems are typically assumed to contribute a small portion of carbon (C) to total C stocks in cocoa agroecosystems. Yet there are almost no direct measurements of cocoa coarse root biomass to support this assumption, presumably due to the difficulty of measuring coarse roots in situ and the risk to farmers' livelihoods. Instead, root biomass is commonly estimated using allometry based on forest data, which might not be accurate for perennial crops given their range of management conditions. In this study, we bridge conventional methods of quantifying coarse root biomass with non-destructive application of ground penetrating radar to estimate cocoa belowground biomass (BGB) and C stocks in an agroforestry system in Ghana. BGB was measured for cocoa grown with shade trees (Entandrophragma angolense or Terminalia ivorensis) and in monoculture. BGB estimates showed good accuracy, with a relative root mean square error of 7% from excavated plants. It was estimated that 15-year-old cocoa hold approximately 6.0 kg C plant−1 in coarse root biomass and have a root to shoot ratio of approximately 0.23. However, the results indicate that proportionally more biomass was allocated to roots for cocoa grown in mixture with shade trees. Plot scale estimates show that cocoa roots contributed 5.4-6.4 Mg C ha−1, representing 8-16% of C stocks in all live tree biomass (cocoa + shade trees), depending on shade tree management. Our findings illustrate a promising approach for non-destructive BGB inventories of perennial crops. It is highlighted that although commonly used pan-tropical allometric equations may broadly function in estimating BGB for cocoa, this approach assumes proportional allocation between aboveground biomass and BGB, which may translate into inaccuracies in C stock inventories across diverse cocoa agroecosystems. [ABSTRACT FROM AUTHOR]

Although Ghana is a leading global cocoa producer, its production and yield have experienced declines in recent years due to various factors, including long-term climate change such as increasing temperatures and changing rainfall patterns, as well as drought events. With the increasing exposure of cocoa-producing regions to extreme weather events, the vulnerability of cocoa production is also expected to rise. Supplemental irrigation for cocoa farmers has emerged as a viable adaptation strategy to ensure a consistent water supply and enhance yield. However, understanding the potential for surface and groundwater irrigation in the cocoa-growing belt remains limited. Consequently, this study aims to provide decision-support maps for surface and groundwater irrigation potential to aid planning and investment in climate-smart cocoa irrigation. Utilizing state-of-the-art geospatial and remote sensing tools, data, and methods, alongside in-situ groundwater data, we assess the irrigation potential within Ghana's cocoa-growing areas. Our analysis identified a total area of 22,126 km 2 for cocoa plantations and 125.2 km 2 for surface water bodies within the cocoa-growing regions. The multi-criteria analysis (MCA) revealed that approximately 80% of the study area exhibits moderate to very high groundwater availability potential. Comparing the MCA output with existing borehole locations demonstrated a reasonable correlation, with about 80% of existing boreholes located in areas with moderate to very high potential. Boreholes in very high potential areas had the highest mean yield of 90.7 l/min, while those in low groundwater availability potential areas registered the lowest mean yield of 58.2 l/min. Our study offers a comprehensive evaluation of water storage components and their implications for cocoa irrigation in Ghana. While groundwater availability shows a generally positive trend, soil moisture and surface water have been declining, particularly in the last decade. These findings underline the need for climate-smart cocoa irrigation strategies that make use of abundant groundwater resources during deficit periods. A balanced conjunctive use of surface and groundwater resources could thus serve as a sustainable solution for maintaining cocoa production in the face of climate change., (© 2023. Springer Nature Limited.)

Increasing the genetic base of current parental cacao varieties grown in West Africa with clones that are able to perform well under marginal conditions could improve cacao production. Survival and yield of 30 different cocoa clones of more recent introductions were compared with five parental clones of improved cocoa varieties under natural field conditions in Ghana. A randomized complete-block design with five replications was used to evaluate the 35 clones for the following traits: percentage survival, increase in trunk cross-sectional area (TCSA), canopy spread, bean mass and bean yield. Significant (p< 0.05) clone effects for all traits and broad-sense heritability range of 0.16–0.51 were observed. Bean mass and bean yield varied from 0.90 to 1.44 g and 149 to 467 kg/ha, respectively. Bean yield and TCSA was positively and moderately correlated (r = 0.46;p< 0.01). Clones A 1/197, ICS 70 and MO 20 outperformed the best control clone for both survival and yield, which could be used in cacao breeding to improve production under marginal conditions in Ghana. [ABSTRACT FROM AUTHOR]

• Fertilizer effects on cacao were studied on fruit, tree and plantation level. • Fertilizer application stimulated pod production in the late rain season in West Africa. • Fertilizer application increased pod size and bean content but not pod number. Fertilizer application in cacao production systems in West Africa yields highly variable results, ranging from no effect to doubling of the yield. Mechanisms underlying yield responses to increased nutrient availability are still largely unkown. In this study, we assessed how fertilizer application affects pod development and production of cacao trees in a full sun cocoa system in Côte d'Ivoire and a shaded cocoa system in Ghana. We monitored pod growth over time and the number of pods produced simultaneously on the trees in the minor and major harvest seasons. Furthermore, we measured nutrient concentrations in cherelles and beans and husks of developing pods in the major harvest season to estimate the total nutrients allocated to developing pods per tree. Lastly, we performed detailed yield measurements (number of pods, location in the tree (canopy or trunk), pod size and bean content) in 2020 for the plot in Côte d'Ivoire. Our results showed that, in the major harvest season, pods on fertilized trees grew wider (average: 15.4 cm) than pods on unfertilized trees (average: 11.9 cm). A higher pod growth rate resulted in a larger final pod size; larger pods took longer to mature. In the major harvest season, more cherelles on fertilized trees than on unfertilized trees reached maturity despite having an equal or lower nutrient content. Competition for assimilates rather than nutrients seems to induce cherelle wilt. In pods past wilting stage, fertilizer application slightly influenced nutrient dynamics of developing pods but not the final nutrient content in ripe pods. Lastly, increased nutrient availaibility did not change the absolute number of pods a tree produced annually. However, fertilizer application did increase the estimated annual dry bean yields from 2260 kg ha−1 to 2930 kg ha−1 by increasing the number of pods that developed during the major harvest season, when pods were heavier and the bean weight within the pods was relatively higher. [ABSTRACT FROM AUTHOR]

Previous research indicates that some important cocoa cultivated areas in West Africa will become unsuitable for growing cocoa in the next decades. However, it is not clear if this change will be mirrored by the shade tree species that could be used in cocoa-based agroforestry systems (C-AFS). We characterized current and future patterns of habitat suitability for 38 tree species (including cocoa), using a consensus method for species distribution modelling considering for the first time climatic and soil variables. The models projected an increase of up to 6% of the potential suitable area for cocoa by 2060 compared to its current suitable area in West Africa. Furthermore, the suitable area was highly reduced (14.5%) once considering only available land-use not contributing to deforestation. Regarding shade trees, 50% of the 37 shade tree species modelled will experience a decrease in geographic rate extent by 2040 in West Africa, and 60% by 2060. Hotspots of shade tree species richness overlap the current core cocoa production areas in Ghana and Côte d'Ivoire, suggesting a potential mismatch for the outer areas in West Africa. Our results highlight the importance of transforming cocoa-based agroforestry systems by changing shade tree species composition to adapt this production systems for future climate conditions., (© 2023. The Author(s).)

Côte d'Ivoire and Ghana, the world's largest producers of cocoa, account for two thirds of the global cocoa production. In both countries, cocoa is the primary perennial crop, providing income to almost two million farmers. Yet precise maps of the area planted with cocoa are missing, hindering accurate quantification of expansion in protected areas, production and yields and limiting information available for improved sustainability governance. Here we combine cocoa plantation data with publicly available satellite imagery in a deep learning framework and create high-resolution maps of cocoa plantations for both countries, validated in situ. Our results suggest that cocoa cultivation is an underlying driver of over 37% of forest loss in protected areas in Côte d'Ivoire and over 13% in Ghana, and that official reports substantially underestimate the planted area (up to 40% in Ghana). These maps serve as a crucial building block to advance our understanding of conservation and economic development in cocoa-producing regions., (© 2023. The Author(s).)

Cacao swollen shoot virus causes cacao swollen shoot disease of Theobroma cacao (cacao) plants. At least six cacao-infecting Badnavirus species- Cacao swollen shoot Togo A virus , Cacao swollen shoot Togo B virus (previously known as Cacao swollen shoot virus ), Cacao swollen shoot CE virus , Cacao swollen shoot Ghana M virus , Cacao swollen shoot Ghana N virus , and Cacao swollen shoot Ghana Q virus -are responsible for the swollen shoot disease of cacao in Ghana. Each of these species consists of a multiplicity of strains. The New Juaben strain, the most virulent cacao swollen shoot virus strain in Ghana, belongs to the Cacao swollen shoot Togo B virus species, and is a commonly used strain in laboratory transmission assays. Infection of cacao trees with multiple strains of the virus is common and new evidence suggests that these coinfections may have resulted in the emergence of recombinant strains of the virus. The impact of these emerging recombinant strains on disease severity is uncertain. This review focuses largely on the discovery of cacao swollen shoot virus in Ghana, diversity of the virus strains, molecular characterization, propagation of virus infection in cacao plants, emergence of recombinant virus strains, vector-mediated transmission of the virus, and the management of the cacao swollen shoot disease in Ghana. It also contains sections on the botany and origin of the cacao tree, its introduction to Ghana, the role of cacao swollen shoot disease in facilitating Ghana's independence from Britain, and a brief history of chocolate., Competing Interests: The author(s) declare no conflict of interest.

• Farm management affect cocoa canopy health and flower intensity. • Proximity to shade trees influences cocoa fruiting and beans quantities. • Proximity to shade trees reduces capsid infestations and fruit wilt. • Black pod disease in cocoa doubles under rainfall from 1400 to 1850 mm. • Rainfall and proximity to shade trees influence cocoa health and productivity. The susceptibility of cocoa to harsh climatic conditions is evident in cocoa growing areas in Ghana, and climate distribution models show reduced cocoa suitability to climate change. We assessed how cocoa health and productivity were affected by varying climate conditions for 4 years in 23 cocoa farms along a gradient of low rainfall/high temperature in the north to high rainfall/low temperature in the south of Ghana's cocoa belts. Twenty cocoa trees per farm (in total 460) were observed and scored for their canopy condition, flower intensity, and damaged pods due to mirids, cocoa shield bugs, and black pod disease (BPD). Harvested pods and extracted dried cocoa beans were evaluated to ascertain yield/productivity. Insect pest damages to pods were on average 2.3 ± 0.8, 2.2 ± 1.0, and 3.0 ± 0.7 pods tree−1 year−1 in the south, middle and north, respectively. The healthiest and highest yielding trees were in the rainy south at 0.99 ± 0.02 kg dry beans tree−1 followed by the middle (0.84 ± 0.02 kg) and the north (0.60 ± 0.01 kg). BPD infection was highest in the south at 1.1 ± 1.1 pods tree−1 year−1, followed by the middle (0.7 ± 0.8), and the north (0.4 ± 0.6). Within sites variability in rainfall and temperature was not found to affect yields significantly. The variability in cocoa performance and occurrence of pests and diseases observed within sites may thus be caused by farm management practices that are key to the enhancement of productivity at site level. We recommend regular pruning of cocoa and shade trees to increase aeration and prevent BPD in high rainfall areas, and an increase in shade tree components in dry regions for insect pest management in cocoa systems. [ABSTRACT FROM AUTHOR]