| North American Vitis species and interspecific hybrids have been the source of rootstocks for Vitis vinifera for the last century. In this study, germplasm collection, morphological evaluation and random amplified polymorphic DNA (RAPD) analysis of native Vitis were made to determine their current status; areas for investigation included north-central Texas, western Texas and New Mexico. Known geographical pockets of grapevines were visited, with specimens taken and identified by comparison to herbarium collections and published descriptions. In locals where more than one species existed, many natural interspecific hybrids with varying morphological characteristics had become established. In North Central Texas, two areas were visited. The first encompassed parts of was Tarrant, Parker and Wise counties where three grapevine species (V. mustangensis, V. berlandieri, and V. vulpina) and many interspecific hybrids were observed. The second was Wilbarger county where V. acerifolia was found growing. West Texas was primarily populated with V. acerifolia with the exception of the Silver Falls Canyon area in Crosby County where hybrids of V. acerifolia, V. arizonica, and V. x doaniana were observed. In New Mexico, two areas were visited: San Miguel County (North Central region), where V. acerifolia, V. arizonica, V. treleasei and V. x doaniana were observed and Otero County (southern New Mexico) where V. arizonica was observed. A rich diversity of Vitis germplasm appears to remain in these habitats.; In this study, extensive polymorphism was detected with the Vitis spp. within the various geographic regions. Eighty-seven initial primers were screened with only twenty-one revealing adequate polymorphism for the continuation of the study. Within the Crosby population unit, many of the plants were morphologically identified as a hybrid of V. acerifolia, but revealed only a low genetic relatedness to the plant previously identified as this species. This also occurred in the San Miguel population unit, but fewer individual plants were a suspected hybrid with this species. V. arizonica was observed as a potential progenitor to the population in both Crosby County, Texas and San Miguel County, New Mexico, which is north of its known distribution. This plant and V. treleasei are thought to be very similar plants. |
