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United States Department of Agriculture

Agricultural Research Service

Research Project: DEVELOPMENT OF AN INTERNATIONAL MARKER ASSISTED SELECTION PROGRAM FOR CACAO

Location: Subtropical Horticulture Research

Title: Status of cacao breeding in Ghana

Authors
item Padi, Francis -
item Opoku, Stephen -
item Adomako, Boamah -
item Adu-Ampomah, Yaw -
item Motamayor, Juan -
item Kuhn, David
item Schnell Ii, Raymond
item Takrama, Jemmy -

Submitted to: Plant and Animal Genome Conference
Publication Type: Abstract Only
Publication Acceptance Date: January 3, 2010
Publication Date: January 15, 2010
Citation: Padi, F.K., Opoku, S.Y., Adomako, B., Adu-Ampomah, Y., Motamayor, J.C., Kuhn, D.N., Schnell Ii, R.J., Takrama, J. 2010. Status of cacao breeding in Ghana. Plant and Animal Genome Conference. 1.

Interpretive Summary: Theobroma cacao, the source of cocoa beans for chocolate, is an important tropical agriculture commodity that is affected by a number of fungal pathogens and insect pests, as well as concerns about yield and quality. We are trying to find molecular genetic markers that are linked to disease resistance and other important economic traits to aid in a marker assisted selection (MAS) breeding program for cacao to ensure a reliable supply of cocoa for the US confectionary industry. Currently there are about 500 molecular genetic markers for cacao and we are taking advantage of the cacao genome sequencing project and specifically the sequencing of the cacao leaf transcriptome to expand that to greater than 50,000 single-nucleotide polymorphism (SNP) markers. We will use these markers to improve the resolution of our current genetic maps and to find associations between specific SNPs and advantageous traits such as disease resistance or higher yield. Our results are important to scientists and breeders in cocoa producing countries who are breeding cacao with improved disease resistance and, eventually, to cacao farmers in Ghana who will benefit from superior disease resistant and more productive cultivars produced through our co-operative MAS breeding program with the Cocoa Research Institute of Ghana.

Technical Abstract: Research into cocoa improvement has made a considerable impact on the productivity of the crop in West Africa. Much of the germplasm distributed to farmers have been of Upper Amazon origin following the realisation of their higher agronomic worth over the local Trinitario and Amelonado germplasm. However, breeding objectives have remained largely unchanged since formal breeding started in Ghana over seven decades ago. Increasing ravages by the cocoa swollen shoot virus disease (CSSVD), Phytophthora pod rot, and attack by insect pests have resulted in low yields. Successes realised in developing clones with tolerance to CSSVD, and with resistance to pod rot are yet to make an impact at the farm level. Through a USDA/MARS Inc. led research, these breeding gains are being consolidated through the use of molecular marker technology. Loci with significant effect on traits of agronomic value are being mapped, and integration of these results into the existing breeding programme is providing planting materials buffered against the effects of the key pests. Broadening the genetic base of breeding materials underpins the current research drive with the evaluation of clones from populations that were under-utilised for breeding, and of clones with resistance to pests that are still alien to West Africa. The Seed Gardens that supply planting materials to farmers are being supported with genetic fingerprinting of hitherto released planting materials. Together, these efforts will improve the productivity of the crop and help sustain the livelihoods of millions of farm families, and of the economies of West African States.

Last Modified: 4/17/2014