Granule-bound starch synthase (GBSSI) gene phylogeny of wild tomatoes (Solanum L. section Lycopersicon [Mill.] Wettst. subsection Lycopersicon)

Eight wild tomato species are native to western South America and one to th e Galapagos Islands. Different classifications of tomatoes have been based on morphological or biological criteria. Our primary goal was to examine th e phylogenetic relationships of all nine wild tomato species and closely re lated outgroups, with a concentration on the most widespread and variable t omato species Solanum peruvianum, using DNA sequences of the structural gen e granule-bound starch synthase (GBSSI. or waxy). Results show some concord ance with previous morphology-based classifications and new relationships. The ingroup comprised a basal polytomy composed of the self-incompatible gr een-fruited species S. chilense and the central to southern Peruvian popula tions of S, peruvianum, S. habrochaites. and S. pennellii. A derived clade contains the northern Peruvian populations of S. peruvianum (also self-inco mpatible, green-fruited), S. chmielewskii, and S. neorickii ( self-compatib le, green-fruited), and the self-compatible and red- to orange- to yellow-f ruited species S. cheesmaniae, S. lycopersicum, and S. pimpinellifolium. Ou tgroup relationships are largely concordant with prior chloroplast DNA rest riction site phylogenies. support S. juglandifolium and S. ochranthum as th e closest outgroup to tomatoes with S. lycopersicoides and S. sitiens as ba sal to these, and support allogamy, self-incompatibility, and green fruits as primitive in the tomato clade.