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United States Department of Agriculture

Agricultural Research Service

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Location: Subtropical Horticulture Research

2011 Annual Report

1a. Objectives (from AD-416)
The Zamia pumila L. complex (Cycadales: Zamiaceae) is a distinctive, monophyletic, diploid (2n =16) assemblage of populations restricted to the West Indies and southeastern U. S. that is currently considered to encompass either a single polymorphic, or nine distinct species. They are important landscape ornamentals in USDA Zones 9-11. The proposed research seeks to simultaneously complete extensive microsatellite DNA and phylogeographic sequence analyses using single copy nuclear genes across the complex and apply these data to various systematic, evolutionary, conservation and biogeographic questions. Results of this project will be interpreted within the context of the complex environmental history of the region. We anticipate that an understanding of the genetic structure of the populations of this complex will help to delineate future conservation strategies, and serve as a model for population level studies of other rare Caribbean plant taxa.

1b. Approach (from AD-416)
Twenty-five to 50 individuals from 1-10 populations from each island in the West Indies known to harbor extant Zamia populations [Bahamas (Andros, Eleuthera, Grand Bahama, Great Abaco, Long Island, New Providence), Cuba (15-20 populations), Grand Cayman, Jamaica, Hispaniola, Puerto Rico] will be sampled. Populations from Puerto Rico, Dominican Republic, Jamaica and four of six Bahamian islands have already been sampled. Collections on Cuba will be supported by non-Federal funds. Twenty-five populations from Florida sufficient to cover the geographic breadth of the distribution of Zamia throughout the southeast U. S. will also be sampled. It is estimated that the total number of populations that will be sampled will range from 80 to 120, with 3600-4500 individuals genotyped with 25 SSR primers, and 1200 individuals will be sequenced across 10 nuclear genes. Bayesian approaches, Maximum Likelihood and the coalescent model will form the framework by which the SSR data will be analyzed. Phylogeographic analysis will be conducted with new software applications that handle gene tree heterogeneity, and a phylogenetic approach for evaluating conservation priority in the group will be evaluated.

3. Progress Report
this project is related to inhouse objective 2: Development and application of new or improved horticultural evaluation procedures and genetic marker-based approaches for genetic diversity assessment of tropical/subtropical ornamental crop genetic resources. Florida International University (FIU) post doctoral fellow, working in our laboratory, has been screening single copy genes isolated from Zamia for informative variation across a test panel of Caribbean Zamia populations. At present we have eight genes that look very promising, and hope to add two more bringing the total to ten. Population sampling in Florida has been completed. The remaining areas to be sampled include the Cayman Islands and Cuba. As National Science Foundation funds cannot be used for research in Cuba, National Geographic Society funding was applied for by the Montgomery Botanical Center, and we have received word that this proposal has been funded. FIU cooperator is currently negotiating with Cuban authorities to obtain permits and licenses for specimen collections in Cuba. We have successfully optimized primers for nine new microsatellite DNA loci, and genotyping of the Puerto Rican, Jamaican and Dominican Republic populations with these new primers is ongoing. The ARS principal investigator attended the International Botanical Congress in Melbourne Australia and presented a paper on the project. A minority undergraduate intern was mentored this summer by the Cooperator.

4. Accomplishments

Last Modified: 10/17/2017
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