Cocoa introductions into Ghana

Cocoa breeding and selection programmes in Ghana and other West African countries have been based largely on existing cultivated populations or on few collections of wild cocoa. The most widely used cocoa germplasm derives from the material collected by F. J. Pound during the periods 1937-1938 and 1942-1943 and distributed as the Iquitos Mixed Calabacillos (IMC), Nanay, Parinari, Scavina, and the Pound series of clones. This material collected in the Upper Amazon region has been particularly successful, suggesting that cacao would be greatly improved if more germplasm material were provided for use by breeders. Maintaining adequate genetic variability in cocoa germplasm collection, essential for sustainable cocoa production, can be realised through active and conscious germplasm acquisition. Because there is the risk of accidentally introducing diseases and pests along with cocoa germplasm material, effective indexing procedures, together with the availability of final quarantine houses in individual producing countries, are essential to ensure that introduced materials are free of diseases and pests. To be successful as breeding material for producing improved varieties for farmers, the introductions must have some desirable characteristics acceptable to chocolate manufacturers and farmers.Les programmes de reproduction et de sélection de cacao au Ghana et dans d'autres pays de l'Afrique occidentale ont été fondé en grande partie sur les populations de cultures existantes oú sur un tous petit nombre de collections de cacao sauvage. Le germeplasme de cacao le plus utilisé sur une grande étendue vient de matières ramassées par F. J. Pound en 1937-1938 et en 1942-1943 et distribuées sous les noms d'Iquitos Mixed Calabacillos (IMC), Nanay, Parinari, Scavina et Pound comme des séries de clones. Une succès particulier a été réalisé avec cette matière ramassée de la région de Haute Amazone. Ce succès suggère que même de plus grandes améliorations en cacao pourraient être possible si beaucoup auraient été disponible pour utilisation par les phytogéticiens. Le maintien de variabilité génétique adéquate en collection de germeplasme de cacao est essentiel pour la production durable de cacao et ceci pourrait être réalisé par acquisition active et consciente de germeplasme. Puisqu'il y a le risque d'introduire par hasard les maladies et les insectes nuisibles avec la matière de germeplasme du cacao, les procédures efficaces d'indexation, ainsi que la disponibilité de salles de quarantaine finale dans chaque pay producteur sont essentiel pour assurer que les matietes introduietes sont sans maladies et insectes nuisibles. Pour réussir comme matière de reproduction pour la production de variétés améliorés pour les agriculteurs, les introductions devraient avoir quelques caractéristiques désirables er acceptables aux fabriquants de chocolat et aux agriculteurs. Ghana Journal of Agricultural Science Vol. 39 (2) 2006: pp. 22

Applying SNP marker technology in the cacao breeding programme in Ghana

In this investigation 45 parental cacao plants and five progeny derived from the parental stock studied were genotyped using six SNP markers to determine off-types or mislabeled clones and to authenticate crosses made in the Cocoa Research Institute of Ghana (CRIG) breeding programme. Investigation was based on the 5\u2019 nuclease SNPassay using Illustra Hot Start mix Ready-To-Go PCR strips and BioTek FLx800TBP Fluorescence Microplate Reader. In a group of six cacao plants labeled as PA150 clones and another five labeled as Pound7, one clone in each group was unambiguously determined as off-type or mislabeled. Similarly, in a cohort of 23 PA7 "clones", four genotypes were differentiated. Cross-checking the fidelity of five progeny from the parental stock under study, it was established that no errors were made in the crossing. The most significant outcome of this study, however, was that out of the four categories of 23 PA7 candidate parental trees only one category can be comparable to the reference clone in the International Cacao Germplasm collection, Trinidad (ICG,T); thus informing the need for further work to find the correct clone among these for the breeding programme. It was thus concluded that thissimple yet cutting-edge genotyping procedure can be used in applied cocoa breeding programmes in a cocoa producing country. This work represents a first step in the genotypic characterisation of the CRIG germplasm collection and Seed Gardens.Au cours de cette recherche, 45 plants de cacao parentaux et 5 descendants d\ue9rivant du stock parental ont \ue9t\ue9 g\ue9notyp\ue9 en utilisant 6 marqueurs SNP, afin de d\ue9terminer les clones mal \ue9tiquet\ue9s et d\u2019authentifier les croisements effectu\ue9s dans le programme d\u2019am\ue9lioration de l\u2019Institut de Recherche sur le Cacao au Ghana (CRIG). Cette \ue9tude a \ue9t\ue9 bas\ue9e sur les 5' nucl\ue9ases SNP en utilisant des bandes PCR "Hot Start mix Ready-To-Go PCR strips" et un Lecteur Microplat \ue0 Fluorescence "BioTek FLx800TBP". Au sein d\u2019un groupe de six plants de cacao \ue9tiquet\ue9 PA150 et d\u2019un autre groupe de cinq \ue9tiquet\ue9 Pound 7, il a \ue9t\ue9 d\ue9termin\ue9 sans ambigu\ueft\ue9 qu\u2019un clone par groupe \ue9tait mal \ue9tiquet\ue9. De fa\ue7on similaire, quatre g\ue9notypes diff\ue9rents ont \ue9t\ue9 identifi\ue9s dans une m\ueame cohorte de clones 23PA7. En v\ue9rifiant la fid\ue9lit\ue9 de cinq descendants issus du stock parental \ue9tudi\ue9, il a \ue9t\ue9 \ue9tabli qu\u2019aucune erreur n\u2019avait \ue9t\ue9 faite lors du croisement. Le r\ue9sultat le plus significatif de cette \ue9tude a \ue9t\ue9 que, sur quatre cat\ue9gories de 23 candidats PA7 de souches parentales, une seule pouvait \ueatre comparable au clone de r\ue9f\ue9rence dans la collection Internationale du Germoplasme de Cacao, Trinidad (ICG,T), d\ue9montrant ainsi la n\ue9cessit\ue9 de travaux suppl\ue9mentaires pour d\ue9terminer le clone exact parmi ceux \ue9voqu\ue9s pr\ue9c\ue9demment. Il a ainsi \ue9t\ue9 conclu que cette m\ue9thode avant-gardiste de g\ue9notypage, pourtantsimple, peut \ueatre utilis\ue9e dans les programmes appliqu\ue9s d\u2019am\ue9lioration du cacao dans un pays producteur. Ce travail repr\ue9sente une premi\ue8re \ue9tape dans la caract\ue9risation g\ue9n\ue9tique de la collection du germoplasme CRIG et jardins semenciers

Prospects of using cassava as temporary shade for cocoa in degraded areas

There have been significant advances in breeding for cocoa varieties with high yield in Ghana and elsewhere. The best yield so far achieved was in Malaysia, where 6000 kg. ha.-1 year, representing only 16-20% of the yield potential of cocoa was recorded. Recent evidence suggests that yield in cocoa is source-limiting (as only 2% of cherelles pass the wilting stage) and not sink limiting. There appears to be a considerable scope for increasing yield of coca through management practices. Cocoa, in comparison to many perennial crops, has a general requirement for shade. Cocoa, therefore, is traditionally planted under mixed forest shade trees. The forest trees serve as permanent shade and plantain is usually planted as temporary shade (during establishment of new farms). However, plantain succumbs to drought in denuded areas and has proven to be unsuitable for use as temporary shade in marginal areas. It is being contended that the provision of optimal shade could maximise cocoa production. Four cassava varieties (Manihot spp.) were planted as temporary shade tree in September 1995 at three spacing (1.2 m x 0.6 m; x 1.2 m and 1.2 m x 2.4 m) at Akumadan. The level of shade provided by the canopies and the control (plantain shade) were assessed, using two matched EEL Light-master Photometers. The cocoa seedlings were transplanted at 1.2 m x 1.2 m spacing under the cassava shade treatments in May/June 1996. The experimental design was a split-plot with three replications. The results show that the survival rates of cocoa seedlings during the two drought seasons following field transplanting were improved by an average of 14% over the plantain shade with the best performing cassava variety showing 20% and the least 8%, receptively. The growth of cocoa seedlings assessed by height and girth measurements was not affected by the shade treatments. Sixty three percent of the seedlings from the cassava shade plots (compared to 48% in the control) jorquetted by the third year after transplanting, an indication of better establishment. JOURNAL OF THE GHANA SCIENCE ASSOCIATION Volume 2 No. 3 (2000) pp. 158-16

Optimising growth in relation to light regime and development of "improved robusta" coffee

Coffee breeding at the Cocoa Research Institute of Ghana over the past decade has focused on the improvement of the local Robusta coffee which has poor agronomic attributes including low yield. These breeding efforts have resulted in the development of a clonal material which has consistently shown better establishment, faster growth and development and higher yields over the local robusta. The experiment being reported here forms part of a series of trials designed to investigate growth requirements of the improved clonal material so as to maximise its potential. Transplanted seedlings were grown under three levels of artificial shade viz:- 25, 50 and 100 per cent of full-day light (FDL). Shading was provided by slats of bamboo supported on wooden posts. Growth data was recorded at monthly interval. Biomass production under the 50% FDL treatments was significantly greater than the 100% and 25% FDL treatments. Seedlings grown under the 25% and 100% FDL were significantly taller than those grown under the 50% FDL treatment. There were no significant differences in stem girth between the treatments. Root biomass was significantly greater in seedlings grown under the 100 and 50% FDL treatments (differences between the 100 and 50 were not significant) than those of the 25% FDL treatment. The overall picture indicates that a nursing shade of 50% FDL should be provided during establishment of the improved robusta coffee clones. Interplanting with food crops should be managed such that optimum of 50% FDL could reach the coffee canopy. JOURNAL OF THE GHANA SCIENCE ASSOCIATION Volume 1 Number 1, July (1998) pp. 12-1

Influence of the position of detached cocoa pod inoculated with phytophthora palmivora on the development of lesion number and lesion size

An experiment was conducted at the Cocoa Research Institute of Ghana (CRIG) to determine if there were any interactions between Phytophthora infection at the distal, proximal and mid-region positions of cocoa pods. The number and size of lesions in nine different cocoa clones were counted and measured at the three different positions of the pod. There were significant differences (