The University of Reading has gained an international reputation for cocoa research since the early 1980’s. Custom built greenhouse facilities allow plants to be grown under conditions simulating cocoa-producing regions, facilitating innovative research on how the crop responds to its environment. The genetic resources database and quarantine facility hosted by the University support international cocoa research and breeding by enabling scientists to find out about and exchange planting materials, whilst minimising the risk of spreading devastating pests and diseases. Excellent links with institutes in the tropics have resulted in joint projects to study and conserve the genetic diversity of the crop, to improve crop establishment, and to detect and control pests and diseases. Such projects have established the University of Reading as a globally important centre for cocoa research.
Cocoa (Theobroma cacao) is cultivated throughout the humid tropics, including regions of West Africa, Central and South America and South-East Asia. The crop provides an important income for small-holder farmers.
The cocoa beans are primarily used by the confectionary industry to produce chocolate. Cocoa butter is also used for cosmetic products.
Obstacles to production
Many varieties grown by farmers have a low potential yield. Furthermore, farmers have to contend with pest and disease outbreaks, whilst climate change is likely to lead to more challenging growing conditions.
Meeting the Challenges
The natural genetic variation that exists in cocoa may be exploited in order to breed new varieties that have ‘built in’ resistance to pests and diseases, higher yields and greater tolerance to environmental stresses.
The International Cocoa Quarantine Centre at Reading (ICQC,R) provides research institutes working on cocoa with distinct genetic types (‘genotypes’) for use in their crop-breeding programmes. Plant material is received from genebanks, principally the international cocoa collections in Trinidad and Tobago (CRC) and Costa Rica (CATIE), and tested for the presence of diseases over a two-year period. Plant material, in the form of budwood, has been provided to over thirty institutes in cocoa-growing countries worldwide.
Crop breeders can also take advantage of the International Cocoa Germplasm Database (ICGD), which is the main source of information on the origin, characteristics and location of different cocoa types available worldwide.
Research for the future
Interactions with the Environment
Research at the University of Reading is investigating how distinct cocoa genotypes respond to environmental variables (water stress, temperature, light and CO2) both at a physiological and molecular level. Research relating to climate change will broaden our understanding of how cocoa plants will respond to a changing environment and help to identify traits that breeders can select for in order to maximise future productivity.
We have collaborative projects with institutes in Ghana, Nigeria, Malaysia and Trinidad. These include studies on field techniques to improve the establishment of young plants, responses to water stress and intercropping cocoa with other fruit trees.
Cryopreservation techniques have been developed at the University of Reading that may be used to store copies of important cocoa genotypes frozen in liquid nitrogen to ensure their long-term conservation. Furthermore, molecular fingerprinting techniques have been used to identify mislabelled cocoa accessions and to characterise the genetic diversity of the crop.
Pest and Disease Research
A molecular technique has been developed at the University to complement traditional methods for the detection of cocoa swollen shoot virus disease in quarantine procedures. On-going research is examining the optimal timing of interventions against mirids; sap-sucking insect pests that causes heavy damage to cocoa trees.