GCGRA Research Projects (15)

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Mabang Megakarya Selection Programme (MMSP) - Consolidation Phase.

Funded by GCGRA and CRIG/COCOBOD, CRUK Ltd, The Embassy of the Netherlands in Accra, Mars, Mondelez International
» Cocoa Research Institute of Ghana
(2013 to 2018)
Researcher: Mr. E.Nsiah (Consultant G. Lockwood)
The supply of improved planting materials to farmers is a vital component in ensuring the sustainability of cocoa production. A public/private partnership between Ghana Cocoa Board (COCOBOD), Embassy of the Kingdom of the Netherlands to Ghana, GCGRA and its sister organisation CR(UK) Ltd, Mars and Mondelez International contributed over €4million to the continuation of a major breeding programme, the Mabang Megakarya Selection Programme (MMSP) over four years. MMSP’s work will lead to Ghana’s seed gardens supplying farmers with new varieties which have been tested for their performance in an area affected by the devastating Megakarya form of Black Pod disease. In the longer term it will also develop improved clonal varieties which will be at the heart of the modernisation of cocoa production.

Evaluation of predictive tests for resistance to black pod disease in Ghana

Funded by GCGRA
» Cocoa Research Institute of Ghana
» Kwame Nkrumah University of Science and Technology, Kumasi, Ghana
(2010 to 2011)
Researchers: D. Nyadanu (Supervisors:Dr. Boamah Adomako, Dr. F. Amoah, Dr. Lockwood (Advisor))
A research project in Ghana to test whether the leaf disc and/or detached pod tests for black pod resistance can be used to predict the rank order of disease incidence of the 16 clones in a completed clone trial and of the general combining abilities (gcas) of 5 and 10 parents in two completed field trials.

Intercropping Cocoa with Economic Shade Trees.

Funded by GCGRA and Cadbury-Kraft, CRIG
(2007 to 2011)
Researchers: Prof. P.Hadley, Dr. A.Daymond
A joint project between CRIG, Cadbury International (Kraft), GCGRA and The University of Reading to assess the performance of hybrid and clonal cocoa grown under Avocado or Terminalia shade trees or without shading.

Mabang Megakarya Selection Programme (MMSP).

Funded by GCGRA and LNV Sustainable Cocoa Subsidy Scheme (Dutch Buffer Stock) and CRIG/COCOBOD
» Cocoa Research Institute of Ghana
(2005 to 2009)
Researcher: Mr. E.Nsiah
A major new breeding programme with the objective of new planting materials with high yield in the presence of damaging pests and diseases, and which can deliver fermented and dried cocoa beans of traditional Ghanaian quality.

Farmer Based Elite Germplasm Identification and Multiplication in Côte d'Ivoire and Ghana.

Funded by GCGRA
» Centre National Recherches Agriculture, Cote d'Ivoire
» Cocoa Research Institute of Ghana
(2001 to 2003)
Researcher: Abdoulaye Traore
A two year research project which established somatic embryogenesis technology at both CNRA and CRIG and used this to propagate promising selections which had been identified by farmers.

Entomopathogenic Fungi for Control of Mirids in Ghana

Funded by GCGRA
» Centre for Agriculture and Biosciences
» Cocoa Research Institute of Ghana
(1999 to 2001)
Researcher: Dr George Oduor
This project was initiated to find, isolate and identify suitable fungal pathogens which could be used to develop an environmentally friendly biocontrol technique to control mirids (capsids), an insect pest which cause substantial damage to the cocoa crop in West Africa. The objectives were to isolate suitable pathogens from mirid populations in Ghana, demonstrate the technical feasibility of cocoa mirid control using fungal pathogens and train Ghanaian scientists in the principles of insect pathology and production of fungal entomopathogens. It complements a larger CABI/CRIG project which was funded by the UK Government (DFID). Staff from the Cocoa Research Institute of Ghana (CRIG) were trained in various aspects of insect pathology both in the laboratory in CABI (UK), CABI-ARC (Kenya) and through on-the-job training in Ghana. Surveys for pathogens in the different cocoa growing regions in Ghana recovered a number of fungal pathogens but only Beauveria bassiana was considered to be worth evaluating as a potential mycoinsecticide. Four other isolates of B. bassiana from cocoa mirids in Papua New Guinea were studied alongside the Ghanaian one. Bioassays against the mirid Sahlbergella singularis did not show any significant differences in the pathogenicities of these isolates. Studies conducted at different temperatures (23, 28 and 33OC) on the rate of growth on artificial medium, intensity of sporulation and viability of both dry spores and spores formulated in oil, of the different isolates identified isolate 382948 (originally isolated from S. singularis in Ghana) as the most promising one for development into a biopesticide. A technique for mass producing B. bassiana on sterilised boiled rice was developed and utilised. Further work is now required in refining formulation, and conducting field trials in order to evaluate the efficacy of this potential biopesticide against cocoa mirid.

Long-term Physiology Trial

Funded by GCGRA
(1995 to 2001)
Researcher: P. Hadley
The intention was to set up a series of long-term multi-locational experiments to analyse the growth and yield potential of a number of contrasting cocoa clones. Sites were established at Almirante Cacau, Bahia, Brazil and Bontu Morso, nr. Kumasi, Ghana but difficulties in establishing common planting materials eventually led to a re-consideration of the project. The site at Bontu Morso was subsequently used in the BCCCA/Bangor University/FORIG project ‘Improving the productivity and sustainability of cocoa farms in West Africa through the utilisation of native forest trees in agroforestry systems’ and the GCGRA/CRIG/Cadbury International project ‘Intercropping cocoa with economic shade crops’.

Diagnostic procedures for detection of Cocoa Swollen Shoot Badnavirus Isolates

Funded by GCGRA
» Cocoa Research Institute of Ghana
(1988 to 2000)
Researcher: Dr. S. Sackey/Rita Osei
Cocoa Swollen Shoot Virus (CSSV) disease has a serious impact on cocoa production in many areas of West Africa though it is not known to occur in the main cocoa areas of the Americas or Southeast Asia. It is one of the most challenging diseases to detect/diagnose both in the field and during the quarantine process since the leaf symptoms of many strains are difficult to distinguish from those caused by mineral deficiencies, and moreover, since viral infections may remain latent/asymptomatic for several years. At the start of this project in 2000, a review of the CSSV detection methods reported in the literature indicated that it was still difficult to unequivocally diagnose cocoa swollen shoot badnavirus infections, since with the exception of electron microscopy and host symptom induction in seedlings, the various diagnostic practices could not be relied upon to universally detect all isolates/infections. To increase the range of strains that the primers could detect, a nucleotide sequence database was compiled on a segment of virus genome covering thirty-six CSSV isolates. Even though PCR DNA products were obtained from all the selected virus isolates, cloning and nucleotide sequencing proved difficult. Thus nucleotide sequences were generated from only a few isolates. The second part of the project was to design new primers based on a new consensus of that part of the virus genome defined by the badna primers. The consensus generated from the few CSSV isolates were used in conjunction with sequences from other viruses associated with tropical crops typically found in Ghanaian cocoa farms, i.e. Discorea alata (yam), banana, and sugarcane, and some typical weeds, i.e. commelina, and kalenchoe. The new primers were characterized to determine optimal conditions for PCR. In the third part of the project, the primers were assessed for their ability to generate amplification products from CSSV infected tissue from these same 36 isolates. It was shown that unlike the universal primers of Lockhart and Olszewski (1983) all but a few of the samples tested produced only one DNA amplification product of the expected 600 base pair molecular weight. Selected amplification products were cloned and sequenced and it was confirmed that they were virus-coded. The cloned DNAs were used as templates for the synthesis of non-radioactive labelled probes for dot blot hybridisation analysis of crude virus DNA extracts, and differentiated between virus DNA and uninfected (healthy) Amelonado cocoa DNA. The project was carried out in part as a postgraduate research project and Ms Rita Nana Konadu Osei submitted her thesis in partial fulfilment of the conditions for the award of the M.Phil. degree in Biochemistry from the University of Ghana in December 2000.

Laboratory and field evaluation of neem seed water extract with different spraying nozzles for control of capsids

Funded by GCGRA
» University of Ghana, Kade, Ghana
» Cocoa Research Institute of Ghana
(1995 to 1996)
Researcher: Prof Afreh-Nuamah


Funded by GCGRA and Cocoa Research Unit, Trinidad
(1988 to 1993)
Researcher: Paul Dartey (Supervisor:Dr. Keith Hardwick)
Abstract from PhD Thesis (University of Liverpool, 1993) of Paul K A A Dartey. The main aim of this project was to investigate ways of improving the reliability of establishment through the use of water storing polymers. Important subsidiary alms were to evaluate posslble advantages of using the polymer to i)raise seedlings in the nursery, ii) improve bare root transplant procedure and iii) carry nutrient ions as well as water. Evaluations were completed by comparing water requirements of seedlings with additional water reservoirs created with various polymer treatments The water requirements of cocoa seedlings under a range of environmenta conditions were successfully estimated from water culture systems with a novel electronic technique. Experiments in controlled environment rooms with compost:polymer (P4) mixtures showed substantial increses in available water and significant extensions of the seedling survival period under drought compared with controls, though higher polymer levels than previously recommended for other crops were needed for significant effects. A mulch treatment was also valuable in conserving water. Field trials in the dry-season in Trinidad were less successful. Neither polymer alone nor combined with mulch significantly extended seedling survival but the dry season was somewhat extreme and observations were not possible regularly enough to detect any short extensions to survival. The field situation is complicated by the presence of competing weeds and redistribution (loss) of water from the reservoir in the planted root-ball to the surrounding dry soil. Further experiments would be needed at individual field sites for a fully effective evaluation of P4. Whilst P4 use in compost did not improve the quality of nursery seedlings, it did reduce the frequency of watering required and greatly enhanced the efficiency of the bare-rooted transplant technique. A new technique for P4 use is developed and is strongly recommended for Ghana. Use of antitranspirant did not prove effective. P4 retained nutrient ions but rapid leaching probably makes its immediate use as a combined fertilser and water carrier non-viable. Conclusions from a simple cost:benefit analysis, based on Ghana details and carried out for various modes of P4 use are that its use for bare-root procedures should be very cost effective but use for ameliorating soil via back-fill in field plantings of ball-rooted seedlings is an expensive insurance though chearer manufacture inthe third world would make this more feasible

Effect of metabolites of Aspergillus niger Van Tiegham and some fungicides on the physiology of Phytophthora palmivora (Butl.) Butl. and on the survival of cocoa (Theobroma cacao L.) seedlings

Funded by GCGRA and University of Ghana
(1992 to 1992)
Researcher: T.Y Annan (Supervisor:Dr. G.T. Odamtten)

Biological Control of Damping-Off of Cocoa (Theobroma cacao L.) Seedlings and Stem Canker Caused by Phytophthora palmivora (using Aspergillus niger)

Funded by GCGRA and University of Ghana/Govt of Ghana
(1991 to 1991)
Researcher: S. P-K Entsie (Supervisor: Dr. G.T. Odamtten)
Samuel Paa-Kwesi Entsie (1992) MPhil Thesis, University of Ghana Summary: The fungus Aspergillus niger to be used in attacking the saprophytic phase of Phytophthora palmivora in soil and in stem as canker was present in the soil of the selected cocoa farms at Suhum, Kade and Nankese (Eastern Region, Breman (Central Region) anj Fume (Volta Region) throughout the year. Total population of soil fungi resident in the top (0-5cm depth) layer was generally 2-5 per cent higher than what existed at the lower (5-lOcm depth) level. Total fungal population was generally low (1.9 3.8 log10CFU/g) from December to April during the dry season and thereafter increased reaching peak value (4.0-4.6 log10CFU/g) in May-July in the major rainy season and September-October in the minor rainy season. Population of A.niger in the soil from the selected cocoa farms differed considerably throughout the sampling period; the farms at Suhum, Kade, Nankese, Breman and Fume showed unique phenology of A.niger propagules. The pH of the soil also varied as follows throughout the year: Suhum (pH 6.5-7.8), Kade (pH 5.6- 6.8), Nankese (pH 6.8-8.0), Breman (pH 5.8-6.7), Fume (pH 6.8-7.8). The top 0-5cm depth recorded pH's that were 2-4 percent higher than the lower 5-10cm depth of soil. The moisture content range of soils from the selected farms are as follows:Suhum (12.4-32.0 per cent), Kade (12.1-22.3 per cent), Nankese 2?-26.8 per cent , Bremen (6.5 -21.7%) and Fume (8.6- 23.2 per cent). Moisture content of top soil (0-5 cm depth) was 2-8% lower than what existed in deeper (5-10cm depth) layers. In order to augment A niger populations in cocoa farm soil, three substrates were tested for their ability to support rapid growth of A niger. The best growth of A niger at 35’C was obtained on blended dry cocoa leaves. The fungus covered the entire petri plate (12.5cm diameter) in about 5 days; it took 21 days to cover the same plate containing blended dry pawpaw leaves and dry plantain leaves was clearly unstuiable as the fungus grew sparingly and took 3 months (90 days) to cover the petri plate. Germination and growth of cocoa seedlings sown in pots containing unsterilized cocoa farm soil amended with A niger (raised on blended dry cocoa leaves) was markedly similar to seedlings raised in A niger-free unsterilized cocoa farm soil. There was no significant difference (P =0.05) in the height, dry weight of stem. root and leaves of all the seedlings after 8 weeks growth in their respective soils. Furthermore, ? seeds of 20 plants belonging to 15 Families and 21 genera germinated and developed to maturity in both non-sterile control soil and in soil amended with A.niger. A niger failed to produce in native soil the characteristic metabolite which is known to depress height and growth of cocoa and other seedlings. Culture filtrate of Asperfillus niger required for studies on the effect of metabolite of the fungus on pre and post-emergence damping off of cocoa seedlings as well as stem canker caused by P. palmivora was provided by cultures grown in V-8 Broth of pH 2.3 at 35’C for 4 days. A niger culture filtrate protected Amazonia, Amelonado variety, Clones T79/501,PA7/808 and NA32 from severe damping-off when beans were placed for 30 min. 1:1-1:2 v/v dilution of filtrate in the presence of P. palmivora zoospores prior to sowing in soil. There was varying levels of resistance/susceptibility to P.palmivora infection depending on the variety/clone used. Filtrate dilution of 1:1 v/v depressed height of seedlings by about 4.5 per cent. When the beans were iwuersed in 1:1 1:2 v/v dilution of A.niger culture filtrate for·30min, 60mln and 120min before artificial inoculation with zoospores of P.palmivora, 90 per cent of T79/501 seedlings survived pre-and post emergence damping off after 10 weeks growth in soil; 80 per cent of Pa7/808 and 50 per cent of Na32 clone survived during the same period of growth. Control beans soaked in distilled water prior to artificial inoculation with P.palmivora zoospores virtually failed to germinate. There was no statistical difference (P < 0.05) between results obtained after 30min, 60min and 120 min soaking in 1:1 v/v dilution of A.niger. External application of culture filtrate of A.niger (1:1 - 1:2 v/v dilution) to soil variably depressed canker formation and symptoms arising from it in cocoa seedlings of crosses T63/971 x T60/887; T65/971 x AMEL; T85/799 x Pa7/808; T85/799 x T65/283 and ALPH B63xS84. Cross T85/799 x Pa7/808 was the most resistant variety followed by T85/799 x T65/283. The cross between ALPH B63 x S84 was the most susceptible to stem canker infection. Other studies reported in this thesis show that P. palmivora could be isolated from soil throughout the year on the selected cocoa farms. The inoculum was 11.4-24.1 per cent higher in the top soil (0-5cm depth) than in the bottom soil (5-lOcm depth). The farmers did not adhere to the cultural practice of burning infected pods on the farm. This resulted in a high percentage (58-82 per cent) of farms acting as reservoir of the pathogen. The nutrient composition of the soil (Organic matter Carbon content, inorganic elements available Nitrogen and Phosphorous etc) and the prevailing microclimatic conditions on the farms presumably acted in concert to augment epiphytotic induction of the disease.

The development of in vitro collecting and izozyme characterization of cocoa germplasm

Funded by GCGRA and CRU/UWI, IBPGR
(1985 to 1988)
Researcher: J.A. Yidana (Supervisor: Lyndsey A. Withers)
Two distinct but related aspects were investigated: development of an in vitro collecting method for andn ii) isozyme characterization of cocoa (Theobroma cacao) germplasm Standard tissue culture incolulation procedures were modified into a simple method for in vitro collecting. Washing of explants before and after sterilisation and the use of a sterile air-flow cabinet during inoculation were eliminated. Antimicrobial compounds were used as surface sterilants and as medium additivies. The fungicides Sportak Alpha Braxo 500, Tilt MBC, Bardew and FBC Protectant Fungicide were effective as surface sterilants when used in combination with "Boots" water sterilising tablets (trade name Sterotabs; Boots Chemical Company Ltd Nottingham, UK). All of the fungicides except FBC Protectant Fungicide were effective medium additives. The antibiotics tested were ampicillin, erythromicin, riamvein and trimethoprim but only rifammycin, used alone or in combination with trimethoprim, was effective. A standard procedire in which explants are sterilised with a mixture of Boots water sterilising tablets (10/100ml) and FBC Protectant Fungicide (0.05%) and inoculaated onto a medium containing Tilt MBC (0.10%) and rifamycin (0.015%) has been recommended. Cultures prepared by this procedure can be maintained clean for 5 to 8 weeks with 30 to 60% success. Although the cultures produced shoots during this period, attempts to root them were unsuccessful. Factors that affect the survival of cultures are discussed. A total of 18 enzymes were examined on polyacrylamide and/or starch gels. Of these, 9 produced multiple bands, 2 produced a single band each while 7 produced unsatisfactory resolution. The enzymes that produced multiple bands were ACP, LAP, EST, G6P, DH, CP, SOD, MDH, MNR and PER. ADH and GDH produced one band each. Feroxidase isozymes (PER) were the most extensively studied using different tissues and plants at different developmental stages. Variation in stem bark was the most consistent and was used to group all cocoa genotypes studied into 3 classes. Peroxidase isozymes in 5 wild Theobroma species were also examined.

Growth of Crinipellis perniciosa in cocoa resistant and susceptible to witches' broom

Funded by GCGRA
(1983 to 1986)
Researcher: O A Danquah (Supervisor: Dr. B.E.J. Wheeler)
Danquah, O-A (1986) Growth of Crinipellis perniciosa in cocoa resistant and susceptible to witches' broom. PhD Thesis, Imperial College, University of London The growth of two isolates representative of the two pathotype populations on cultivated cocoa of Crinipellis perniciosa, the causal agent of witches’ broom was studied in seedlings with Scavine 6 as one parent. One isolate from Pichilingue in Ecuador (pathotype A) induced significantly more hypertrophy, grew more rapidly up the plant and colonised the tuees at any one level more extensively than did the other isolate from Trinidad (pathotype 8). For both isolates·there were highly significant correlations between amounts of fungus in the tissues and the hypertrophy produced but no indication that they differed in their ability to induce hypertrophy. In seedlings infected with the Trinidad isolate, groups of necrotic cells associated with the intercellular hyphae of C. perniciosa were found 5 weeks after inoculation. Similar sites of necrosis developed more slowly and less frequently in seedlings infected with the Pichilingue isolate. Thus at 9 to 12 weeks after inoculation, there were significantly more sites of necrosis and more necrotic cells per site in seedlings infected with the Trinidad isolate and more unaffected hyphae in seedlings infected with the Pichilingue isolate. When basidiospores of the two isolates were germinated in water extracts from Scavina 6 seedlings, the germ-tubes of the Pichilingue isolate were significantly longer than those of the Trinidad isolate. This different in germ-tube growth appeared to be associated with the phenolic and alkaloid components. However, no significant correlation was obtained between the numbers of hyphal fragments in Scavina 6 seedlings and germ-tube length in extracts of tissue from the same seedlings. Similar studies of the two isolates in seedling of other cocoa cultivars further indicated the ability of the Pichilingue isolate to grown in those with Scavina parentage though in others eg Amelonado, both isolats grew equally well. Further tests with extracts of other cocoa cultivars were inconsistent and inconclusive. An attempt was made to study the significance of cell death in the C.perniciosa/ccoa relationship by preparing cocoa callus and cell suspensions, but the techniques used were not entirely successful.

Studies on the Rapid Propagation of Cacao (Theobroma cacao L.)

Funded by GCGRA
» Wye College, University of London, UK
(1983 to 1986)
Researcher: F.M Amoah (Supervisor:Dr. Ray Fordham)
Franklin Manu Amoah (1986) Studies on the Rapid Propagation of Cacao (Theobroma cacao L.). PhD Thesis, Wye College, University of London. Summary Vegetative propagation is important for the rapid multiplication and improvement of selected clones of cacao for research and breeding programmes and the establishment of plantations. A review of literature on plant propagation with special reference to cacao has been carried out. The effects of several environmental and physiological factors as well as pretreatments to seeds and cuttings on the propagation of cacao (Theobroma cacao L.)have been investigated. Techniques have been developed for the intensified production of your cacao from seeds, rooted cuttings and the Nutrient Film Technique (NFT). A growing medium of 30’C favoured rapid rooting of cuttings and the growth of young plants by the NFT. Leaf area of about 80cm2 favoured success of rooting and bench budding/grafting. A mixture of Indole-3-Butyric Acid (IBA) and a-Naphthalene acetic acid (NAA) in equal proportions at a total concentration of 6000ppm applied as 10 seconds quick dip favoured rooting of cuttings whilst Gibberellic Acid (GA3) at 500ppm or Gibberellic Acid and 6-Benzylaminopurine (BAP) mixture in equal proportions at a total concentration of 500ppm favoured rapid shoot growth of cuttings and bench budding/graftlings. Addition of mineral nutrients to the flowing solution inhibited both rooting and bud break of cuttings rooted by the NFT. Studies on the effect of individual elements (N, P and K) on rooting also revealed that single node cuttings of cacao rooted best in distilled water than in any other solution. Cuttings rooted faster in the NFT than under mist and growth rates of young plants growing NFT conditions were approximately twice the rate observed for plants grown in standard potting compost. Marginal leaf scorching, which is a common occurrence in cacao, has been observed to be related to local deficiencies of calcium in the affected areas resulting from reduced water uptake by plants; however, this does not occur under NFT conditions where there is a continuous supply of water to the plants. Recommendations are made on improved techniques for the intensified production of young cacao.
"Research that is focused on the needs of the West African cocoa farmer"