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In Situ Conservation of America's Wild Grapes

2001; American Society for Horticultural Science; Volume: 36; Issue: 2 Linguagem: Inglês

10.21273/hortsci.36.2.232

2327-9834

Diane S. Pavek, Warren F. Lamboy, Edward J. Garvey,

Fermentation and Sensory Analysis

Received for publication 22 May 2000. Accepted for publication 13 June 2000. We are grateful to Joseph Kirkbride, U.S. Dept. of Agriculture, Seed Herbarium, for requesting the following loans for study and to the staff members of the following herbaria for access to specimens (using standard herbarium abbreviations): TEX, TAMU, CM, FM, FLAS, BH, US, NA, NLU, UNM, GA, MO, and NY. We thank the Endangered Resources Branch of Texas Parks and Wildlife for location and status information. We appreciate information and access to grape populations given by the staff members from the Merritt Island Wildlife Refuge, Fla.; Jonathan Dickinson, Myakka River, and Hillsborough River State Parks, Fla.; and Garner, Guadelupe River, Pedernales River State Parks and the Hill Country State Natural Area, Texas. We thank Cui Tiecheng from Xian Botanical Garden, China, and John Asbury, Temple, Texas, for field assistance; and Paul Schmalzer, Dynamac Corp., Kennedy Space Center, Fla. for sharing his field observations in Florida. The comments of two anonymous reviewers and Stan Hokanson made this a better paper. We are grateful to the late Michael Moore, who allowed us access to his Vitaceae treatment in manuscript form and for very helpful taxonomic discussions. The cost of publishing this paper was defrayed in part by the payment of page charges. Under postal regulations, this paper therefore must be hereby marked advertisement solely to indicate this fact. Characterizing genetic diversity and its distribution throughout species’ ranges furthers our understanding about the adaptation and survival of wild species and ensures that genetic resources are available for study or potential use in research and breeding programs. Both in situ (i.e., preserving wild populations in their natural habitats) and ex situ approaches are important to the conservation of genetic resources (Bretting and Duvick, 1997; Dulloo et al., 1998; Merezhko, 1998; Nevo, 1998). Most of our staple crops are native to other continents, which means that in situ conservation of wild crop relatives in America will have a limited role in the U.S. Dept. of Agriculture– Agricultural Research Service (USDA–ARS) National Plant Germplasm System (NPGS). However, for wild crop relatives native to the United States, in situ conservation is desirable, since the populations would continue to be exposed to coevolution (host–pest/ pathogen), natural selection (environmental and biotic stresses), and other pressures (mutation, gene flow, and genetic drift) that are the keys to changing adaptations and diversities. The resulting genetic diversity in these populations of wild crop relatives is an underutilized reservoir of potentially novel resistances and tolerances (Burdon and Jarosz, 1989; Maxted et al., 1997; Zencirci et al. 1998). In situ conservation can complement the existing ex situ collections in the NPGS. The crop curator is the essential link in the NPGS between evolutionary conservation and utilization. In establishing in situ conservation programs, the curator will screen wild populations for genetic distinction throughout a species’ range, prioritize the sampled populations as candidates for in situ conservation, arrange conservation agreements with landowners, and make the germplasm available to researchers and breeders. Where appropriate, curators need to implement in situ programs because the risk of losing native genetic resources increases with the habitat loss, land conversion, and changes in land use occurring across America (Waller, 1996). We undertook a 2-year project to examine the feasibility of establishing in situ conservation sites for three grape (Vitis L.) species native to the United States. The initial phase focused on rock grape (Vitis rupestris Scheele), a species of concern to conservationists because of extensive habitat loss. Out of seven rock grape populations proposed as in situ conservation sites, four were finally established as the first such conservation sites within the NPGS. In the final year of the project, work focused on populations of Caloosa grape (Vitis shuttleworthii House), an endemic to central and southern Florida, and sweet mountain grape (Vitis monticola Buckl.), an endemic on the Edwards Plateau in central Texas. Caloosa and sweet mountain grapes are important to agriculture for breeding potential, but are not state-listed conservation concerns. Caloosa grape is reported as being resistant to Pierce’s disease (Xylella fastidiosa Wells et al.), a virulent disease that prevents Vitis vinifera L. (i.e., the commercial wine and table grape species) from being grown in the southeastern United States (Banks et al., 1999; Loomis, 1958; Reisch and Pratt, 1996). However, in the vineyard setting, the wild Caloosa grape may express differential susceptibility to Pierce’s disease (J. Grinstead, Meramec and Vinewood Vitis Vineyards, Rolla, Mo., pers. comm., 1998). Caloosa grape has a globally threatened conservation status of vulnerable (Walter and Gillett, 1998). Currently, the state of Florida does not monitor this species (B. Lenczewski, Environmental Reviewer, Florida Natural Areas Inventory, Tallahassee, Fla., pers. comm., 1997). Although difficult to propagate, sweet mountain grape is tolerant to calcareous soils and to grape phylloxera (Daktulosphaira vitifoliae Fitch) and other diseases (Mullins et al., 1992; Reisch and Pratt, 1996; Wapshere and Helm, 1987). Sweet mountain grape is not currently a species of concern in Texas (D. Scott, Texas Biol. and Conserv. Data System, Austin, Texas, pers. comm., 1998). Both of these species are vulnerable to grazing and often occur only in fencerows where they escape herbivory. Additionally, frequent prescribed or recurrent burns (every 3 to 4 years) will eliminate Caloosa grape (herbarium specimens and personal observation, 1998). The objective of this study was to use molecular and morphological data to characterize populations throughout their ranges and propose in situ conservation sites, following a strategy initially used for rock grape populations.