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ARS Home » Northeast Area » Beltsville, Maryland (BARC) » Beltsville Agricultural Research Center » Sustainable Perennial Crops Laboratory » Research » Publications at this Location » Publication #345541

Research Project: Genetic Diversity Assessment of Cacao and Other Tropical Tree Crop Genetic Resources

Location: Sustainable Perennial Crops Laboratory

Title: Molecular characterization of a cacao germplasm collection in Yunnan, China using Single Nucleotide Polymorphism (SNP) markers

Author
item WANG, BOYI - Yunnan University
item MOTILAL, LAMBERT - University Of The West Indies
item Meinhardt, Lyndel
item Mischke, Barbara
item Zhang, Dapeng

Submitted to: Tropical Plant Biology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/11/2020
Publication Date: 9/1/2020
Citation: Wang, B., Motilal, L., Meinhardt, L.W., Mischke, B.S., Zhang, D. 2020. Molecular characterization of a cacao germplasm collection in Yunnan, China using Single Nucleotide Polymorphism (SNP) markers. Tropical Plant Biology. https://doi.org/10.1007/s12042-020-09267-y.
DOI: https://doi.org/10.1007/s12042-020-09267-y

Interpretive Summary: Yunnan province in the far southwest of China is a tropical agriculture region and has a large potential to expand cacao production given the rapid increase of chocolate consumption in China. Knowledge of genetic diversity in cacao germplasm available in Yunnan is important for planning future introduction and use of cacao germplasm in Yunnan. Using Single Nucleotide Polymorphisms (SNP) markers, we assessed genetic diversity in the cacao collection maintained in the Xishuangbanna Tropical Botanical Garden in Yunnan and inferred parentage of these accessions. The inferred parentage revealed a large gap of genetic diversity in this collection, in comparison with the genetic diversity that is available internationally. These results suggest that new introductions would increase the representation of genetic diversity in this collection and improve the germplasm foundation for Chinese cacao producers. This information will be used by cacao researchers, extension staff and farmers to improve cacao production in China.

Technical Abstract: Yunnan province is located in the far southwest of China where tropical agriculture makes up a significant part of the provincial GDP. There is a large potential to expand cacao production in Yunnan, given the rapid increase of chocolate consumption in China. China imported 77490 tons of cocoa products (in beans equivalent) in 2015 and the importation has increased 10% each year (on average) over the last 10 years. Knowledge of genetic diversity in cacao germplasm available in Yunnan is important for planning future introduction and utilization of cacao germplasm in Yunnan. Using Single Nucleotide Polymorphisms (SNP) markers, we assessed genetic diversity in the cacao collection maintained in the Xishuangbanna Tropical Botanical Garden in Yunnan and inferred parentage of these accessions. Multi-variant analysis and Bayesian assignment test showed that these introduced cacao germplasm have a narrow genetic background and were mostly comprised of Amelonado hybrids. Of the 88 Yunnan accessions, 59% of the parentage is contributed by Amelonado, 17% by two Upper Amazon Forastero populations and the contribution from the rest of the cacao genetic groups are either very small or negligible. The inferred parentage revealed a large gap of genetic diversity in this collection, in comparison with the available genetic diversity in International cacao genebanks. It also predicts the lack of multi-sources of resistance to major cacao diseases in this collection. The present result therefore suggests that new introductions ought to be taken to increase the representation of genetic diversity in this collection. An improved germplasm collection would serve as a foundation for broader on farm diversity for cacao production in Yunnan, as well as in other tropical regions of China.