Project Number: 6631-21000-012-00
Project Type: Appropriated

Start Date: Apr 18, 2003
End Date: Mar 21, 2008

Objective:
To develop new DNA based markers and utilize currently available markers to characterize populations of Theobroma cacao that are segregating for resistance to Monilia Pod Rot, Black Pod, and Witches' Broom. Markers associated with the resistance genes will be used in a Marker-Aided Selection (MAS) program to select for new varieties with resistance to these three diseases. Screening of disease tolerant materials at collaborating institutions as a global effort including, but not limited to, TARS in Mayagues, Puerto Rico, CATIE in Turrialba, Costa Rica, and EET, Pichilingue Ecuador. Development of related Quality Trait Loci, maps and expressed sequence tags. Development of the integrated molecular/phenotypic database. Analysis of genetic linkages of disease resistance of Theobroma cacao to Crinipellis and Moniliophthora. Through the engagement of a support scientist or similar position, enlarge the range of collection of wild Theobroma cacao material, characterize these accessions, establish in an accepted center for germplasm conservation, e.g., CATIE, CRU/Trinidad, ARS/SAA/TARS; and, conduct field evaluations for disease resistance, production and/or quality traits.

Approach:
Utilize current germplasm located at TARS in Mayaguez, Puerto Rico, CATIE in Turrialba, Costa Rica, and EET, Pichilingue Ecuador. Develop new DNA simple sequence repeat (SSR), single nucleotide polymorphism (SNP), resistance gene homologues (RGH), and WRKY gene markers. Utilize current markers and newly developed markers to map genes controlling disease resistance and use these in a MAS program to develop germplasm resistant to Monilia roreri and Crinipellis perniciosa. Develop new families for selection based on initial mapping data and utilizing MAS to select new productive disease resistant cultivars.