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United States Department of Agriculture

Agricultural Research Service

Research Project: Genetic Improvement of Cacao Through Genomics-Assisted Breeding

Location: Subtropical Horticulture Research

Title: An example of association mapping in Cacao.

Authors
item Gutierrez, Osman
item Schnell, Raymond -
item Motamayor, Juan -
item Kuhn, David
item Tondo, Cecile
item Boza, Edward
item Livingstone, Donald -
item Royaert, Stefan -
item Nagai, Chifumi -
item Phillips, Wilbert -
item Amores, Freddy -
item Lopes, Uilson -
item Takrama, Jemmy -
item Padi, Francis -
item Aikpokpodion, Peter -
item Pokou, Desire -
item Efombagn, Ives Bruno -
item Sounigo, Olivier -
item Epaina, Peter -

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: October 15, 2012
Publication Date: October 20, 2012
Citation: Gutierrez, O.A., Schnell, R.J., Motamayor, J., Kuhn, D.N., Tondo, C.L., Boza, E.J., Livingstone, D., Royaert, S., Nagai, C., Phillips, W., Amores, F., Lopes, U., Takrama, J., Padi, F., Aikpokpodion, P., Pokou, D., Efombagn, I., Sounigo, O., Epaina, P. 2012. An example of association mapping in Cacao.. Meeting Abstract. Seven INGENIC Workshop, Yaounde, Cameroon, October 21-22, 2013.

Technical Abstract: Association mapping and genomic selection have become important methodologies in perennial crop breeding improvement programs for accelerating breeding efforts and increasing the efficiency of selection. They are good alternatives to the classical Quantitative Trait Loci (QTL) mapping approach.The USDA-ARS and MARS Inc. joint cacao research improvement program has developed cacao breeding populations in several countries that are segregating for resistance to Witches’ Broom, Frosty Pod and Black Pod disease, as well as for productivity traits. QTLs associated with these traits have been identified; however, some of these associations are specific to certain populations and they are influenced by their interaction with the environment. Additionally, the majority of these traits are controlled by many genes with small effects. Due to these constraints, Marker Assisted Selection (MAS) and traditional plant breeding methodologies have not been very effective in accelerating the development of cacao varieties with improved yields, excellent flavor traits and superb disease and insect resistance. Advances in high throughput genomic technologies at reduced cost and the sequencing of the cacao genome have allowed the development of thousands of Single Nucleotide Polymorphism (SNP) markers that are currently being used in parental identification, germplasm characterization and the fine mapping of QTLs. Furthermore, the genotype-by-sequencing approach is also currently being used in cacao. Finally, the recent development of robust statistical methodologies for association mapping and genomic selection (GS) make them very attractive for use in cacao breeding. Currently in our research program we are using previously identified QTLs and applying association mapping techniques to evaluate the marker-trait associations across different sets of cacao germplasm and breeding populations from South and Central America, Africa, and Asia. Another goal is to identify loci that could be significantly associated with disease resistance, agronomic and quality traits, in order to later use them as predictors of performance. Selection based on these predictors could lead to faster genetic gains and reduction in the time and cost of releasing superior varieties with high yield, disease resistance and the quality attributes required by the confectionary industry.

Last Modified: 8/1/2014
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