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United States Department of Agriculture

Agricultural Research Service

Research Project: CHARACTERIZING AND CONSERVING THE GENETIC DIVERSITY OF CARYA POPULATIONS

Location: Crop Germplasm Research

Project Number: 6202-21000-032-00
Project Type: Appropriated

Start Date: Apr 18, 2008
End Date: Apr 17, 2013

Objective:
Objective 1: Strategically expand and improve collections of priority Carya genetic resources and associated information. Sub-objective 1.A: Survey existing U.S. domestic collections of Carya, identify material that would fill gaps in NPGS collections, and begin strategically acquiring and characterizing them. The initial priority is to collect Carya myristiciformis (nutmeg hickory) across its range. Sub-objective 1.B: In cooperation with Federal agency collaborators, state Conservation Reserve Programs, Nature Conservancy and Heritage Programs, and private landowners, designate appropriate in situ reserves and establish additional regional Carya plantings. Objective 2: Conserve and propagate Carya genetic resources efficiently and effectively, and distribute disease-free samples and associated information worldwide. Sub-objective 2.A: With ARS collaborators, develop and apply more efficient and effective strategies for conserving the genetic integrity of Carya genetic resources. Sub-objective 2.B: Optimally maintain orchard plantations of grafted cultivar accessions at Somerville (near College Station), Texas, with duplicate plantings at Brownwood, Texas, and distribute seeds and/or cuttings to requestors. Objective 3: As resources permit, strategically genotype and phenotype Carya genetic resources for priority genetic and horticultural traits. Sub-objective 3.A: Incorporate existing characterization data for Carya into GRIN and/or other databases. Sub-objective 3.B: Incorporate existing horticultural evaluation data for Carya into GRIN and/or other databases. Sub-objective 3.C: Extend ongoing cooperative research to assess the relationship between genetic diversity and geographical distribution in Carya via molecular marker assays, and incorporate genotypic data into GRIN and/or other databases.

Approach:
Efforts to strategically expand and improve collections of Carya genetic resources and associated information will give initial priority to collecting Carya myristiciformis (nutmeg hickory) across its range (Objective 1). Information on the distribution of nutmeg hickory will be obtained from a variety of sources, including published accounts, herbarium voucher information, USDA Forest Service Forest Inventory records, State Conservancy and Heritage programs, and personal information. When possible, seeds, graftwood, and collection records will be obtained from local cooperators. Collection trips will be conducted to targeted locations when needed. Attempts will be made in cooperation with Federal agency collaborators, State Conservation Reserve Programs, Nature Conservancy and Heritage Programs, and private landowners, to designate appropriate in situ reserves. C. floridana (scrub hickory) is the most geographically restricted hickory species in the U.S., and it will serve as a model for rational development of in situ conservation in other species. Samples will be collected from the known range of the species, characterized using available molecular tools, and data will be analyzed for patterns of genetic isolation. Implications for resource management will be interpreted and translated into guidelines for designating functional in situ reserves. Efforts to develop more efficient and effective strategies for conserving the genetic integrity of Carya genetic resources (Objective 2) will involve cooperative efforts to determine feasibility of adapting recalcitrant seed cryopreservation protocols for use in Carya. Work will involve developing protocols for harvesting, handling, shipping, viability testing and storage of pecan pollen, and cryopreservation protocols for dormant buds. To strategically genotype and phenotype Carya genetic resources for priority genetic and horticultural traits (Objective 3), there is a need to develop a relational database with capabilities for efficient management of the spatial descriptors related to original collections, spatial descriptors of repository inventories, and genetic data of the NCGR-Carya collection. A database will be structured to appropriately capture many analyses associated with one inventory, and to allow retrieval in association with other inventories of the same cultivar in forms amenable to statistical analyses. To facilitate data entry for Carya into GRIN and/or other databases, efforts will be made to integrate bar coding into field labeling, and Personal Digital Assistants (PDAs) into field data collection. Efforts to assess the relationship between genetic diversity and geographical distribution in Carya via molecular marker assays will be made using collections made from 19 native pecan populations located from Illinois to Oaxaca, Mexico, and will facilitate assessment of the extent of genetic isolation by distance and reveal patterns consistent with environmental adaptation.

Last Modified: 9/21/2014
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