Vitis shuttleworthii, commonly referred to as callose grape, is a wild grape species endemic to Central and South Florida and serves as a valuable genetic resource for the development of subtropical and tropical scion and rootstock cultivars. V. shuttleworthii can thrive in a humid environment and grows readily in nutrient deficient soils. This species is also resistant to anthracnose, downy mildew, Pierce’s disease and root knot nematodes. This study explores the genetic diversity and phylogenetic relationships among V. shuttleworthii populations sampled from diverse regions across Florida. The overarching objective of the current study is to characterize the extent of natural genetic variation within and among populations and to identify promising genetic sources for resistance to key grapevine diseases. DNA obtained from 72 V. shuttleworthii individuals, along with 25 reference grape accessions, were sequenced using the Illumina platform (2 X 150 bp configuration). We identified over 64 million SNPs from the 97 accessions and 376,753 high-quality SNPs were retained for downstream analysis. Phylogenetic and principal component analyses revealed geographically structured clustering among V. shuttleworthii populations, indicating patterns of local adaptation and evolutionary divergence. The phylogenetic tree delineated clear genetic separation between wild Florida populations and cultivated Vitis species or breeding lines. Principal Component 1 accounted for 61.65% of the variance, while Principal Component 2 explained 9.86% of the variance. This spatial genetic structure suggests significant genetic diversity and restricted gene flow across regions. This study highlights the natural genetic variation present within the V. shuttleworthii population and provides a valuable resource for grape breeding programs.
