Fig. 2.

First-degree relationships within the USDA grape germplasm collection. (A) Number of first-degree relationships was evaluated for each of the 583 unique vinifera cultivars. A total of 74.8% of the unique cultivars are related to at least 1 other cultivar by a first-degree relationship, and some cultivars have many first-degree relationships (i.e., >10; SI Appendix, Table S4). (B) Pedigree structure of vinifera is represented as a set of networks. Edges in the network represent inferred first-degree relationships. The vertices, or dots, represent grape cultivars and are colored by grape type (legend). The sample size of each grape type is shown in parentheses. Lone dots represent cultivars with no first-degree relatives in the dataset. Note that one single interconnected network is clearly visible and includes 384 (58.3%) of the 583 unique cultivars that are interconnected by a series of first-degree relationships.