Hybrid Cocoa Research Articles

English

A 2x2 diallel mating design was set up to estimate quantitative genetic parameters after leaf artificial inoculation tests in nursery and field for three consecutive years. F12 and F40 families of two reciprocal crosses viz., F12: ♀SCA12 × ♂ICS40 and F40: ♀ICS40 × ♂SCA12 were used to study heterosis (mid-parent), heterobeltiosis (better-parent), heritability (narrow-sense and broad-sense) and to quantify total polyphenols (TPP) and total flavonoids (TF) contents after inoculation of the leaves of parental and hybrid cocoa genotypes with Phytophthora megakarya. The results of heterosis and heterobeltiosis exhibited hybrid vigor of 86.66 and 85%, respectively. The highest heritability was identified [narrow-sense heritability (h²: 0.668 for F12 and 0.682 for F40) and broad-sense heritability (H²: 0.765 for F12 and 0.672 for F40)] for necrosis length in 2014. With regards to low narrow-sense heritability, it ranged from 0.019 to 0.162 while corresponding broad-sense heritability ranged from 0.476 to 0.562 for biochemical compounds. Among parent clones, ICS40 and SCA12 proved to have the general combining abilities (GCA). The use of these parental lines and understanding the gene flow of tolerance to black pod disease (Bpd) in cocoa will help researchers to develop a targeted breeding approach in generating new generation of tolerant genotypes cocoa. Key words: Cocoa, heterosis, heterobeltiosis, heritability, black pod disease, tolerance.

English

The government of Cameroon is responsible for distributing hybrid cocoa seeds to farmers in Cameroon. These high-yielding and pod rot-resistant hybrids are obtained from self-incompatible commercial clones used for seed production by manual pollination of freshly opened flowers. The experimental procedure for the propagation technique of these clones has never been reported. The objectives of this study are to assess the effect of clone, cutting source and growth regulator concentration on the growth and rooting of cocoa (Theobroma cacao L.) stem cuttings. The experiment consisted of 4 clones (SNK16, ICS40, UPA143 and T79/501; two cutting sources: B1 = orthotropic and B2 = Plagiotropic) and four concentrations of growth regulator (4-indol-3-butyric acid) concentrations (D0 = 0 mg, D1 = 12.5 mg, D2 = 25 mg and D3 = 37.5 mg), thus a 4 × 2 × 4 factorial experiment in a completely randomized block design with 3 replicates was designed. Cuttings were set and monitored weekly for shoot sprouting for 10 weeks and rooting at the 10th week. The following parameters were measured: survival rate, number of cuttings with shoots, number of produced shoots, leaves length, number and length of produced roots. Clone, cutting source and growth regulator concentration significantly affected survival rate, shoot sprouting and rooting of cocoa cuttings at p = 0.05. Overall, cuttings started producing shoots 3 weeks after setting (WAS) and at 10 WAS all the cuttings had rooted. Assessment of cuttings in Clementine propagators showed a survival rate of approximately 75%, with orthotropic cuttings showing higher results than plagiotropic cuttings, whereas, D1 (12.5 mg) was the overall effective growth regulator (IBA) concentration that induced the highest number of roots from all the clones. UPA143 was the clone with highest value for all the factors assessed. The results will be valuable in management decision when producing planting materials by stem cuttings. Key words: Theobroma cacao, vegetative propagation, clone, cutting source, growth regulator concentration, clementine propagator, shoot and root growth.

Enriched cocoa pod composts and their fertilizing effects on hybrid cocoa seedlings

PurposeComposting has the potential to recycle wastes as a means of conserving natural resources. The study was aimed at examining feasibility of producing nutrient-enriched composts from pest infested cocoa pods with chemical amendments and using manure composts as a fertilizing material in cocoa seedling nursery.MethodsCocoa pod waste was composted in static vessels, aerobically, with chemical enrichments (triple super phosphate charged at 0.4% P or urea charged at 0.8% N or poultry manure charged at 22%) along with a control at the Cocoa and Coconut Institute, Papua New Guinea. The reaction (pH) of the composting mixtures (pH) and macro-nutrients dynamics was monitored at periodic intervals. Effect of soil incorporation of cocoa pod manure composts at 10 g kg−1 was assessed on the growth and foliar concentration of macro-nutrients in hybrid cocoa seedlings.ResultsIn the finished manure composts, dry matter loss ranged from 30.6 to 63.3%; greatest in composting mixtures charged with super phosphate and poultry manure. Besides, super phosphate enriched mixture lost small fraction of initial N (6.6%) compared to un-enriched cocoa pod waste (30.2%). Composting mixtures with greater pH values during composting process showed higher losses of N. Super phosphate charged manure compost outperformed the control, in terms of C/N ratio and concentration of macro-nutrients (P, K, Ca, Mg and S). Quality parameters for all the manure composts conformed to the Canadian Compost Guidelines indicating satisfactory standards. Waste cocoa pods enriched with superphosphate did not show any deleterious effects on cocoa seedlings’ growth, rather, improved plant height, dry matter production and foliar N concentration.ConclusionWaste cocoa pods, co-composted with triple super phosphate and poultry manure, produced composts of desirable quality and can be effectively used to fertilize the cocoa seedlings.

Cocoa Seed Garden: a means to disseminating improved plantingmaterials for enhanced national productivity: A review

Cocoa growing in West Africa has historically been dependent on the use of beans from “good-looking” open-pollinated pods in farmers’ field; majority of whose yield, pest and disease tolerance/resistance are scientifically unproven. The low hectarage productivity of 0.3 – 0.5 tonnes/ha from individual farms across Nigeria has poorly supported the national cocoa production. Hybrid cocoa pods have very high breeding value for yield and other economic traits, their use for mass cultivation will increase cocoa productivity. Cocoa seed garden are hectares of established known parental clones of cocoa with an aim of generating hybrid pods through controlled cross pollination. Cocoa Seed garden sites are in fourteen states of Nigeria, Ondo state has the largest cumulative hectarage. By principle, the process of Cocoa Seed Garden entails, selection of parental stocks based on the result from routine test for combining ability among parents within the germplasm, clonal seedling production of selected parents, patterned field establishment of the parental clones and hand pollination of parents to generate hybrid pods. Details of the principle are well discussed and information on the effective Cocoa Seed garden sites in Nigeria is provided

ACCESS TO IMPROVED HYBRID SEEDS IN GHANA: IMPLICATIONS FOR ESTABLISHMENT AND REHABILITATION OF COCOA FARMS

SUMMARYPoor access to improved seeds in West and Central Africa has compromised crop yields and productivity as most farmers source the bulk of their seeds from informal channels. The use of farmer produced seeds has mostly resulted in high seedling mortality thereby presenting challenges to cocoa rehabilitation programmes across the sub region. With the aid of a mobile data collection system (MDCS), the first of its kind to enhance accuracy of survey results in an improved seed supply system through brokerage and linkages among diverse actors, this study assesses Ghanaian farmers’ access to improved hybrid cocoa seeds and provides evidence on the socio-cultural factors that affect field performance of such planting materials. Results show that farmers value a seed brokerage system (SBS), which is facilitated through group bulk purchase, timely acquisition and delivery of seeds. The study also revealed that farm size, land use type and gender have significant effect on survival rate of transplanted hybrid cocoa seedlings over two dry seasons. Regardless of the rehabilitation process, mean survival rate was high (79%) although an 11% (p < 0.000) difference occurred between gender with men recording a higher rate. The majority of farmers prefer cultivating cocoa on forest and fallow lands, implying continues degradation of forest areas. There is therefore an urgent need for a change of mind set, to advocate for land recycling to spare forest areas to thrive.

Microbial succession and the dynamics of metabolites and sugars during the fermentation of three different cocoa (Theobroma cacao L.) hybrids

The intensive efforts to control the “witches' broom” fungus in Brazil have included research on resistant and more productive cocoa cultivars, but the impact of these crosses on cocoa fermentation is not known. To understand the effects of breeding on cocoa fermentation, this work investigated the microbes and chemical compounds present during the fermentation of three highly productive hybrids (PH 9, PH 15 and PH 16). The microbial species present during the fermentation process were similar in all three hybrids, but the populations of lactic acid, acetic acid, and mesophilic aerobic bacteria and yeast in the PH 9 hybrid fermentations were greater than those in PH 15 and PH 16. Lactobacillus fermentum, Lactobacillus casei and Lactobacillus rhamnosus were the predominant species in all hybrid cocoa fermentations. However, the profile of the bacterial community detected by PCR-DGGE was more complex in the PH 9 fermentation. The yeast Saccharomyces cerevisiae was predominant in the all fermentations, followed by Hanseniaspora uvarum and the genus Pichia. A similar profile of substrate consumption (glucose, sucrose, fructose and citric acid) and kinetics of major metabolites (ethanol, acetic acid and lactic acid) was also observed, but the PH 16 hybrid presented the highest concentrations of sugars, acids and alcohols.

Adoption of Some Cocoa Production Technologies by Cocoa Farmers in Ghana

Adoption of the cocoa (Theobroma cacao) production technologies recommended to cocoa farmers by Cocoa Research Institute of Ghana (CRIG) had been low, leading to yield and production levels below potential. To investigate this issue, a formal socio-economic sample survey of 300 cocoa farmers selected randomly, by a multi-stage sampling technique, from all the cocoa growing regions of Ghana was conducted with a structured questionnaire for the individual interviews. The adoption rates of CRIG-recommended technologies such as control of capsids with insecticides, control of black pod disease with fungicides, weed control manually or with herbicides, planting hybrid cocoa varieties and fertilizer application were 10.3%, 7.5%, 3.7%, 44.0% and 33.0%, respectively. Adoption models indicated that credit, number of cocoa farms owned by the farmer, gender, age of the cocoa farm, migration, cocoa farm size, and cocoa yield affected the adoption decisions of cocoa farmers concerning the CRIG-recommended technologies analyzed in this study.

The effect of land use systems on tree diversity: farmer preference and species composition of cocoa-based agroecosystems in Ghana

Traditionally, most cocoa farms are estab- lished by removing the forest understorey and thinning the forest canopy so that cocoa seedlings can grow into productive trees by utilising the forest rent of the newly cleared area and the shade provided by the remaining trees. With the introduction of new hybrid cocoa varieties, there is a gradual shift towards the elimina- tion of shade trees in the cocoa landscape. Farmers have found it necessary to eliminate forest tree species to effect high performance of these new varieties and as a result large areas of forested land are being lost, thereby posing a threat to biodiversity A study was carried out in Atwima, a major cocoa farming district in the Ashanti region of Ghana, to assess the impact of cocoa cultivation on tree diversity. The study also investigated farmers' preferences for tree species retained on cocoa farms as well as their traditional knowledge on tree species and their effect on cocoa cultivation. The assessment consisted of identification and enumeration of all tree species with diameter at breast height greater than or equal to 10 cm, and was carried out on one-hectare plots of: (a) Active Cocoa Farms (ACF), stratified into (i) Mature Cocoa Forest (MCF) and (ii) Young Replanted Cocoa (YRC); (b) Fallow land (FL), and (c) Natural Forest (NF). A total of four one-hectare plots replicated five times (or 20 ha) were enumerated. Tree diversity was more strongly influenced by landuse type than age of cocoa farm. Fallow lands contained a higher tree diversity followed by natural forest, with the active cocoa farms, both mature and young, containing the lowest variety of species. However, stem count was highest in the natural forest followed by FL and ACF. Generally, stem counts of important tree species, as well as those classified as either endangered or vulnerable, were extremely low in the landscape (0-2 per hectare), indicating a critical potential for conservation and rejuvenation. Farmers' preference for trees on cocoa farms was based on their usefulness. Three categories of trees emerged from their classification of trees on cocoa farms: (i) naturally occurring trees that are very useful; (ii) naturally occurring species of minor economic use; and (iii) naturally occurring tree species that are aggressive or incompatible with cocoa. Mul- tistrata cocoa farms are a potential niche for conser- vation, but given the current trends in cocoa replanting, future conservation strategies will have to focus on identified targeted species which are of conservation concern, as well as those that are of value to farmers.

Amino acids, carbohydrates and heritability of resistance in the Theobroma cacao/Phythophthora megakarya interaction.

Summary. The black pod disease of cocoa (Theobroma cacao), caused by Phythophthora megakarya, is responsible for 80% loss of cocoa production in Cameroon. The principal method of ameliorating crop losses is through the use of black pod resistant and high productivity hybrid cocoa clones. In order to assess the possible role of amino acids and carbohydrates in the defence of T. cacao against P. megakarya, comparative analyses (quantitative and qualitative) of sugars and amino acids were carried out on leaves of parental genotypes, ICS95, ICS84 and hybrids (families F25:♀ICS84 X ♂ICS95 and F30: ♀ICS95 X ♂ICS84 ). A reduction in soluble sugar contents of parental genotypes ICS84, ICS95 and 30% of hybrid genotypes was noted under conditions of infection. Qualitative analyses of sugars showed that most cases of infection were characterized by the disappearance of sucrose and the persistence of glucose. Amino acids content increased in 70% of genotypes after injury or infection. In parental tolerant clone ICS84 and hybrid genotypes F3011, F2551 and F2552, proline appeared solely during conditions of infection, suggesting its implication in the defence mechanism of T. cacao against P. megakarya. A significant positive relationship was observed between amino acid contents and the severity of necrosis. There was a very weak relationship between sugar and amino acid contents in parental genotype, and those of the progeny. PCA of the length of necrosis, sugar level, amino acids and phenolics showed that under infection, the increase in content of phenolic compound was concomitant with reduction in amino acid content.

Factors Influencing Adoption of Cocoa Technologies Disseminated by Olam Organisation in Ondo State, Nigeria

The study was undertaken to determine factors influencing adoption of cocoa technologies disseminated by Olam organization to cocoa farmers in Ondo State, Nigeria. Data for the study were collected from thirty cocoa farmers (Olam’s model farmers) through the use of structured interview schedule. Data were analyzed using mean, factor analysis and regression statistics. Results showed that planting of hybrid cocoa seedlings, use of agrochemicals/fungicides, pruning and fermentation were cocoa technologies adopted by farmers. The significant factors influencing adoption of cocoa technologies included age, educational level, household size, no of farm family assisting on the farm, management system adopted, involvement in social organization and source of labour. The result of the varimax rotation revealed that the major constraints to adoption of cocoa technologies were socio-cultural, literacy and financial problems. It was therefore recommended that existing farmers’ organizations should be strengthened through regular meetings and training by Olam organization to enhance rapid dissemination and adoption of cocoa technologies.Key word: Adoption, cocoa technologies and Olam organization

Financial analysis of shaded cocoa in Ghana

The cultivation of cocoa has been an important driver of tropical deforestation glob- ally. Efforts to reverse this trend are focusing on the reintroduction of shade trees to cocoa plan- tations. Shade trees are valuable in enhancing biophysical conditions on cocoa (Theobroma cacao) fields and contribute to biodiversity and product diversification for smallholder producers. Participatory trials of cocoa agroforests planted with indigenous shade tree species were under- taken with farmers in the Atwima District of the Ashanti Region of Ghana, to increase tree volume on cocoa fields while improving rural livelihoods and enhancing environmental sustain- ability. An ex ante financial analysis of the technology was undertaken to assess its economic viability. Input-output data were collected from farmer experiments over three seasons and sup- plemented with data from traditional cocoa fields of varying rotation ages, and secondary data on production in later years of an eighty-year cocoa rotation. A discounted cash flow analysis was carried out to estimate the benefit-cost (B/C) ratio, net present value (NPV), internal rate of return (IRR) and land expectation value (LEV) as well as the sensitivity to a 20% decline in cocoa prices and additional chemical costs for various shade scenarios at a 10% discount rate. It was observed that cocoa production is, in general, profitable. The change from the traditional sys- tem to one with hybrid cocoa raised the IRR from 31% to 57% with planted shade and 67% without, although extra agrochemical costs would tend to reduce the profitability of unshaded hybrid cocoa in particular. The age of maximum LEV for the various scenarios suggests that the optimum economic rotation for the hybrid cocoa is between 18 and 29 years, much less than the traditional system.

Hybrid cocoa tree adaptability and yield temporal stability inRondônia State, Brazil

Hybrid cocoa tree (Theobroma cacao L.) adaptability and yield temporal stability were studied to screen agronomically superior varieties for yield, bean quality and resistance to witches’ broom under the ecological conditions of Ouro Preto do Oeste County, Rondonia State, Brazil. Assessments were based on yield component measurements evaluated at maturity in a randomized complete block experiment. Additionally, the possibility of early hybrid selection, at the initial fructification phase, was investigated. For this, the results obtained from both periods was compared. At maturity, the SCA 6 x ICS 1, PA 150 x SIC 328 and IMC 67 x BE 8 hybrids were superior in the simultaneous analysis of total number of healthy fruits (TNHF), total weight of fresh beans (TWFB) and mean weight of fresh beans per fruit (MWFBF). Using Eberhart and Russell’s methodology, PA 150 x SIC 328 had general adaptability and highly predictable performance for TNHF. The SCA 6 x ICS 1 hybrid also had general adaptability, in spite of indicated low predictability. The IMC 67 x BE 8 cross was adapted to unfavorable environments and had high predictability for TNHF. The SCA 6 x ICS 1 and PA 150 x SIC 328 hybrids behaved similarly for TWFB, showing adaptability to favorable environments and high predictability. IMC 67 x BE 8 showed general adaptability and high predictability for this trait. The three hybrids showed general adaptability and high predictability for MWFBF. On the base of mean performance (or i P values of Lin and Binn’ methodology), hybrid selection was also successful using measurements taken at the initial fructification phase. On the other hand, the Eberhart and Russel’s adaptability and stability parameters depended on the period evaluated.

Yield repeatability and evaluation period in hybrid cocoa assessment

Repeatability estimates were obtained from an experiment carried out in Rondonia state to define the evaluation period necessary to discriminate between cocoa hybrid yields. Data collection involved these traits: total number of fruits harvested (TNFC), total number of healthy fruits (TNHF), total weight of fresh seeds (TWFS), mean weight of fresh seeds per fruit (MNFSF), percentage of wasted fruits (SPWF) and percentage of wasted fruits due to witches’ broom disease (PWFWB). Repeatability estimates were high for the two last traits (values above 0.8) but were relatively low (lower than 0.65) for the others when the ANOVA estimation was performed on data collected at maturity. These estimates indicated that three evaluations are necessary from the 8 th year after planting for efficient selection (accuracy > 70%) for all the assessed traits. When the average of the assessments carried out in two pre-climax years was considered, it was possible to obtain a correlation greater than 0.70 between the real hybrid value and the traits total number of fruits collected and percentage of wasted fruits.

An Integrated Socioeconomic Analysis of Innovation Adoption: The Case of Hybrid Cocoa in Ghana

This study employs a multidisciplinary model to explain the adoption of agricultural innovations in developing economies with reference to hybrid cocoa in Ghana. The empirical evidence shows that, in the adoption of hybrid cocoa, the support that small-scale farmers obtain via their social networks is more relevant than the advantage of farm size enjoyed by large-scale farmers. However, for large-scale farmers, access to a bank loan strongly increases their chance of adoption compared with small-scale farmers. Contacts with extension agents, education, and availability of hired labor also have positive effects on adoption. The social status of the farmers has only an indirect effect on adoption: farmers with higher social status are more likely to obtain a bank loan, and a bank loan has a positive impact on adoption.

Changes in free amino acid, peptide-N, sugar and pyrazine concentration during cocoa fermentation

The free amino acids, peptide-N, reducing sugars (the flavour precursors in cocoa) and pyrazine profiles of mix hybrid cocoa beans fermented in a rotary drum reactor were monitored over a period of 6 days. As fermentation progressed, the acidic free amino acid concentration decreased significantly (P<0·05) by 15%, whereas total, hydrophobic and other free amino acids increased significantly by 148, 280 and 127%, respectively. In terms of hydrophobic/acidic/other free amino acids ratio, the unfermented cocoa beans contained 30%:18%: 52%, whereas those of fermented beans contained 46%: 6%: 48%. Concentrations of peptide-N and total reducing sugars were significantly (P<0·05) increased by 55 and 208%, respectively during fermentation; however, those of sucrose and total sugars decreased significantly (P<0·05) by 89% and 75%, respectively. The unfermented cocoa beans contained no pyrazine; however during fermentation, the 2-methyl-, 2,5-dimethyl-, 2,6-dimethyl-, 2,3-dimethyl-, trimethyl- and tetramethylpyrazine were formed. The two principle pyrazines were tetramethyl- (2099·30 μg kg−1) and trimethylpyrazine (692·00 μg kg−1). © 1998 Society of Chemical Industry.

The establishment and early yield of cocoa intercropped with food crops in Ghana

A cocoa-food crop intercropping trial was set up in 1988 at the Cocoa Research Institute of Ghana, Tafo. The effects of plantain, cassava, and maize as intercrops with cocoa only and in their various combinations on the establishment, growth of the cocoa, and the profitability of the food crops were studied in a randomized block experiment with five replicates. Mixed hybrid cocoa seedlings were planted at 3 m W 3 m and Glyricidia maculata provided permanent shade in all plots. Three years after planting, the sole cocoa with Glyricidia maculata was inferior in growth to the cocoa interplanted with food crops. Cocoa in treatments which included maize showed superior growth and better precocity. Yield of each food intercrop with cocoa only was higher than when combined with other food crops. Sole cocoa gave less revenue equivalent to the operational costs during the establishment phase. The other food crop combinations with cocoa gave net revenue gain in the first 2 years after planting. The economic evaluation of the food crop combinations indicated that treatments which included cassava were the most profitable. Ghana Jnl agric. Sci. Vol.31(1) 1998: 45-53

Doing primary research in a developing economy

In 1992 and 1993 fieldwork was done in the Eastern Region of Ghana to examine why hybrid cocoa, introduced by cocoa institutions, was adopted by some farmers and not others. This report discusses the problems encountered when collecting data, including the low-level of farmers' education, and the lack of official records and sampling possibilities. This article is hosted by our co-publisher Taylor & Francis.

Ant – homopteran interactions in a tropical ecosystem. Description of an experiment on cocoa in Ghana

AbstractOver a period of six years, the presence or absence of 23 species of arboreal insects (13 Homoptera, 1 Heteroptera, 9 ants (Hymenoptera: Formicidae)) was recorded on each of 866 young Amazon and Amazon hybrid cocoa trees at the Cocoa Research Institute, Tafo, Ghana. The general form of the time-series, derived from the proportion of trees occupied by each species, is described. Analysis of 18 of these series, taken either singly or jointly, was carried out using analysis of variance and principal components analysis and the degree of spatial association between 16 of the species was also investigated. For the latter, the number of joint occurrences of pairs of species was compared with the expected number by means of a chi squared test. An index of association was derived from the proportion of occasions on which the difference was significant. For all but four species, there were highly significant differences between annual means in the analysis of variance and, in many, the overall annual trend was downward with time. For those species where significant differences were not shown between years, trends were often apparent on individual plots but were negated because of inconsistencies between plots in the direction of the trend. In the joint analysis of all 18 species by principal components, the first component accounted for approximately 33% of the total variance and could be identified as representing to a large extent the long-term upward or downward trends shown up by the analysis of variance. The second principal component, accounting for a further 13% of total variance, was interpreted as being a further manifestation of the long-term trend, representing a tendency for deviation from the trend line shown up by the first component to become less with time and to approach the trend line in a damped oscillation. This is thought to be partly caused by a drought at the start of the experiment which affected certain species adversely. The third principal component accounted for 11% of total variance and the scores followed an irregular annual cycle which was related to relative humidity. The scores on this axis were high during dry periods of the year and low during wet periods. In the analysis of variance it was found that 13 species showed significant differences in spatial distribution between seasons and, for most, there was evidence for an annual cycle. There was also some evidence of correlation between the seasonal cycles of some insects with seasonal rainfall level or morning or afternoon relative humidity. These same species are important in contributing to the third principal component scores. Spatial association analysis showed eight species to be strongly associated. These fell into three groups with positive associations between members of the same group and negative association between members of other groups. Each group featured an ant-homopteran association, Crematogaster spp. with Planococcoides njalensis (Laing) in group 1, Oecophylla longinoda (Latreille) with Stictococcus spp. in group 2, and Camponotus spp. and Polyrhachis laboriosa F. Smith with Planococcus citri (Risso) and Toxoptera aurantii Boyer de Fonscolombe in group 3. Three other coccids were loosely linked to these groups through particular members, Waxiella sp. nr zonatus (Newstead) to group 1 through Planococcoides njalensis and to group 2 through Camponotus spp. and Phenacoccus hargreavesi (Laing) and Steatococcus spp. to group 2 through Planococcus citri. Changes taking place with time in the relative abundance of members of these groups could be discerned in the trajectories of the first two principal components. The spatial re-arrangements taking place with time of the territories of the major ant species are followed in some detail, and the effect of these changes on Homoptera is discussed.

A comparison of the growth and yield during a 20 year period of Amelonado and upper amazon hybrid cocoa in Ghana

Progeny trials were planted at Tafo in 1952 and 1954 to compare 3 selfed local-Trinitarios, 1 outcrossed and 3 sibbed Upper Amazon progenies and 13 hybrids between Amelonado or local-Trinitarios and Upper Amazons; 1 trial included West African Amelonado. The Amazon hybrids and the outcrossed Amazon were particularly vigorous and precocious and maintained a yield advantage for 20 years. The 13 hybrids were similar in yield potential, but varied in net yield following differential losses from pod diseases, mainly caused by Phytophthora palmivora. Disease losses were lowest on one of the sibbed Amazons and the outcrossed Amazon and lower on Amelonado than on any of the 7 hybrids tested with it; in both trials losses were lower on Amelonado hybrids than on Trinitario hybrids.