Submitted to: Plant and Animal Genome Conference Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: January 13, 2007
Publication Date: January 13, 2007
Citation: Schnell Ii, R.J., Kuhn, D.N., Brown, J.S., Tondo, C.T., Motamayor, J. 2007. Cacao genomics and the development of a marker-assisted-selection program for cacao. Plant and Animal Genome Conference Proceedings. Technical Abstract: Theobroma cacao L. is an understory tree from the Amazon basin that can be cultivated in a sustainable agro-forestry system. Four main genetic groups of cacao are traditionally described: Criollo, Trinitario, and lower and upper Amazon Forastero. Production of cacao in tropical America has been severely affected by two fungal pathogens causing diseases known as witches’ broom (WB) and frosty pod (FP). These, along with another pan-tropical fungal disease, black pod (BP), were responsible for over 700 million USD in losses in 2001. Currently, WB and FP are confined to tropical America; however, commercial populations in West Africa and South Asia are highly susceptible to both diseases. Traditional cacao breeding programs have only been marginally successful in producing resistant material with suitable commercial characteristics. In 1999, the USDA-ARS in collaboration with Mars Inc. initiated a project to apply modern molecular genetic techniques to cacao breeding. The objectives were to develop an international Marker Assisted Selection (MAS) breeding program focusing on disease resistance. Quantitative Trait Loci (QTL) have been identified for resistance to WB and FP and these are being employed in MAS. Large evaluation trials, developed using MAS, are located in Costa Rica, Ecuador, Brazil, and Papua New Guinea with additional QTL evaluation studies in Ghana, Nigeria, Costa Rica, and Ecuador. All these projects are collaborations with national agricultural institutes in the respective countries. The international MAS project is expected to produce new disease resistant cultivars by 2012.