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ARS Home » Southeast Area » Miami, Florida » Subtropical Horticulture Research » Research » Research Project #433544

Research Project: Evaluation of the TARS and SHRS Series of Cacao Germplasm Selections under Colombian Growing Conditions

Location: Subtropical Horticulture Research

Project Number: 6038-21000-025-17-I
Project Type: Interagency Reimbursable Agreement

Start Date: Mar 15, 2017
End Date: Mar 14, 2020

Objective:
The main goal of this collaborative project is the introduction of improved cacao germplasm from the USDA-ARS-TARS and USDA-ARS/MARS/INIAP breeding programs into Colombia. Also the evaluation of on-farm genetic diversity and identification of disease resistance genes in segregating populations. The project has four specific objectives: 1. Establish new cacao performance trials at different locations in Colombia to evaluate disease resistance, agronomic and quality traits of elite clones from the USDA-ARS-TARS and USDA-ARS/MARS/INIAP breeding programs. 2. Identify cacao clones with high levels of black pod (BP; Phytophthora spp.), frosty pod (FP) (Moniliophthora roreri) and witches' broom (WB), (Moniliophthora perniciosa) resistance using phytopathological screening methodology. 3. Assessment of on-farm cacao genetic diversity in five producing regions in Colombia using SNP markers. 4. Utilize SNP markers, linkage and QTL analysis to identify genes associated with resistance to BP, FP and WB in cacao full-sib families developed by CORPOICA.

Approach:
The area under cacao cultivation in Colombia is increasing in response to a growing demand for cacao beans; however, most of the genetic material propagated by growers has been selected from trees identified by farmers as good performers in their fields. Therefore, the majority of the planted varieties are not the product of a plant breeding program since there were not developed from controlled hybridizations. The Colombian chocolate industry needs to be developed upon grafted, high yielding, excellent quality clones with high levels of disease resistance. For this reason, several new cacao clones need to be evaluated across different growing environments in Colombia. This performance evaluation process will efficiently enable the selection of cacao clones with high productivity, excellent quality traits and high levels of black pod (BP), frosty pod (FP) and witches' broom (WB) resistance. Cacao germplasm selections developed by the breeding program at USDA-ARS-TARS and USDA-ARS/MARS/INIAP will be planted at different locations in Colombia in cooperation with CORPOICA. Phenotypic data on resistance to BP, FP, and WP as well as agronomic data will be collected on these trials. Also, in conjunction with CORPOICA scientists, leaf samples will be collected from cacao farms (30 farms per region) located in the 5 regions of the country for DNA extraction and SNP fingerprint analysis. Finally, leaf samples from full sib families segregating for disease resistance traits will be collected also for DNA extraction and SNP fingerprinting. Population structure, linkage mapping and QTL identification soft wares will be used to analyze the data.