Selection for improved quality and resistance to Phytophthora pod rot, cocoa pod borer and vascular-streak dieback in cocoa in Indonesia

• Masterfoods Australia/New Zealand, Australia
• Balai Pengkajian Teknologi Pertanian, Indonesia
• University of Sydney, Australia
• Biotechnology Research Institute for Estate Crops, Indonesia
• Dinas Perkebunan, Indonesia
• Indonesian Coffee and Cocoa Research Institute, Indonesia
• Indonesia, Indonesia
• University of Queensland, Australia

During the last two decades there has been rapid and spontaneous expansion of cocoa production by smallholders in the outer eastern provinces of Indonesia, especially in South and East Sulawesi. The 400,000 smallholders involved have benefited through substantial increases in income and regional development.

Indonesia is now the world's third largest exporter of cocoa after the Ivory Coast and Ghana. However this industry and associated livelihoods are threatened by pest and disease-namely cocoa pod borer (CPB) (larva of the moth Conopomorpha cramerella), phytophthora pod rot (PPR) and other diseases caused by Phytophthora palmivora, and vascular streak dieback (VSD) caused by Oncobasidium theobromae.

Of particular concern is the pod borer, which already affects around 50% of Sulawesi cocoa farms and could rise to 100% in 7-10 years if no remedial steps are taken. In addition there is a real possibility that the pest will spread to West Papua and from there to Papua New Guinea and Solomon Islands.

The project aimed to enhance the infrastructure and capability within Indonesia for the collection, maintenance and screening for pest and disease resistance of different cocoa genotypes, and to use this capability to determine quality characteristics of different cocoa lines.

The research program involved extensive collection of potentially useful genotypes from parts of Indonesia, screening for lines resistant to the diseases, trials of lines from outside Indonesia, and establishment of living collections of cocoa types.
Initial training established the procedures for identification and collection of interesting genotypes. A workshop enabled discussion of the design of field trials to test cultural methods to control VSD, PPR and CPB on infested mature cocoa.
Indonesian scientists then collected a range of cocoa material identified as 'superior' then undertook screening to determine the disease and pest resistance and assess the quality characteristics of the various lines through trials at sites on Sulawesi.
During the exploration for cocoa genotypes at various locations throughout Indonesia, infected leaf and stems (for VSD) or pods (for PPR) were collected. The scientists studied the two main pathogenic fungi by gathering isolates from the pods and stems for molecular typing and by monitoring incidence and severity of the diseases. Laboratory work undertaken in Indonesia and Australia learnt more about VSD.
In view of the variable quality of product from the small farmers, the scientists also undertook quality assessments of the cocoa beans collected from throughout the field site in Southeast Sulawesi. Quality assessment, undertaken at the research laboratory of PT Effem/Mars at Makassar, assessed pod value, cocoa butter content, bean weight and flavour.

The project team supported and trained a core of 20 Indonesian scientists, extension and technical officers, leading to improvements in cocoa extension services. This included the development of linkages to other cocoa projects and organisations in Indonesia. Good relationships were established between scientists in Indonesia, Australia and Papua New Guinea.
The program involved five initial field collections of more than 60 cocoa genotypes with putative resistance to pests and diseases. These materials were supplemented with international selections and lines from earlier field assessments and screenings.
A participatory, on-farm research program in cocoa enabled researchers, extension officers and farmers to work together. This led to a method of farmer-assisted field selection to screen on-farm cocoa genotypes for resistance to pests and diseases.
The team then commenced assessment of vascular streak dieback (VSD) and Colletotrichum disease on grafted clones in field trials. As well laboratory-based studies commenced in Australia and Indonesia to develop protocols for DNA extraction from VSD fungus and to assess the genetic variability and host range of this organism.
Two trials were also established in Sulawesi to evaluate practices for control of Phytophthora diseases.
The reviewer considered that despite some delays the project was on track to develop and evaluate planting materials, cocoa bean quality, farming systems and practices. Expectations seemed high that suitable resistant materials would be identified and, together with improved practices, lead to a more sustainable and reliable cocoa industry in Sulawesi. The two-year timeframe, together with a late start, had made it difficult to complete the schedule.
Project extension would be necessary to allow proper evaluation and testing and to continue to build capacity and strengthen the institutional framework of the Indonesian partner agencies. This would include final publication of results and assessments of the approach; one output would be a summarising handbook in Indonesia Bahasa on pests and diseases of cocoa and methods for their management together with cocoa technology for Sulawesi. ACIAR has accepted this recommendation to extend and the project now has another three years to accomplish its objectives.