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United States Department of Agriculture

Agricultural Research Service

Research Project: Conservation, Genetic Analyses, and Utilization of Subtropical/Tropical Fruit Crops, Sugarcane, and Miscanthus Genetic Resources

Location: Subtropical Horticulture Research

Title: Towards The Identification Of Candidate Genes Involved In Witches' Broom Disease Resistance In Theobroma cacao L.

Authors
item Royaert, Stefan -
item Moore, Michael -
item Santos Araujo, Iona -
item Viana Da Silva, Daniela -
item Martins DE Jesus, Samuel -
item Livingstone Iii, Donald -
item Marelli, Jean-Philippe -
item Kuhn, David
item Gutierrez, Osman
item Correa, Ronan -
item Schnell, Raymond -
item Motamayor Arias, Juan Carlos -

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: January 13, 2013
Publication Date: January 13, 2013
Citation: Royaert, S., Moore, M.J., Santos Araujo, I., Viana Da Silva, D., Martins De Jesus, S., Livingstone Iii, D.S., Marelli, J., Kuhn, D.N., Gutierrez, O.A., Correa, R.X., Schnell, R.J., Motamayor Arias, J. 2013. Towards The Identification Of Candidate Genes Involved In Witches' Broom Disease Resistance In Theobroma cacao L.. Meeting Abstract. Plant and Animal Genome Meeting XXI, January 12-16, 2013 San Diego, CA.

Technical Abstract: 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. Increasing yield, quality and disease resistance are important objectives for cacao breeding programs. Some of the diseases, such as black pod rot (Phytophtora spp), frosty pod (Moniliophthora roreri) and witches’ broom (M. perniciosa), produce significant losses in all or in some of the various production areas around the world. We recently identified associations for witches’ broom (WB) resistance (cushion brooms, more specifically) using 185 simple sequence repeat (SSR) markers and a segregating mapping population of 282 trees at the Mars Center for Cocoa Science (Brazil) between ‘TSH-1188’ (WB resistant) and ‘CCN-51’ (WB tolerant). Later, a more extensive set of trees (459) of the same mapping population has been genotyped with 6,000 SNPs. Phenotypic data including vegetative brooms and cushion brooms for this population was collected from 2008 to 2011 and SNP markers were associated with the different traits. The resulting fine map (3,526 SNPs, 852.8 cM) allowed us to identify significant associations for vegetative and cushion brooms, mainly on linkage groups 9, 6 and 4, and some minor associations on linkage groups 7 and 3. Further strategies, such as phasing of the parents and the offspring in order to reduce the size of the associated regions will be presented. The goal is to identify markers for Marker-Assisted-Breeding, and ultimately identify candidate genes involved in witches’ broom resistance. Our results are important to scientists trying to understand the mechanism of disease resistance and, eventually, to cacao farmers who will benefit from superior disease resistant and more productive cultivars produced through our MAS breeding program.

Last Modified: 8/1/2014
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