ARS | Publication request: SPECIES AND SERIES BOUNDARIES OF SOLANUM SERIES CONICIBACCATA AND PHENETICALLY SIMILAR SPECIES IN SERIES PIURANA (SECT. PETOTA): MORPHOLOGICAL DATA FROM A FIELD STUDY IN PERU

Submitted to: Solanaceae International Congress Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: May 29, 2006
Publication Date: July 30, 2006
Citation: Fajardo, D., Salas, A., Castillo, R., Spooner, D.M. 2006. Species and series boundaries of solanum series conicibaccata and phenetically similar species in series piurana (sect. petota): morphological data from a field study in Peru [abstract]. Solanaceae International Congress Proceedings. p. 152.

Technical Abstract: Solanum series Conicibaccata is composed of about 40 wild potato (sect. Petota) species distributed from central Mexico to Bolivia, and form the second largest series in section Petota. They contain diploids (2n=2x =24), tetraploids (2n=4x =48) and hexaploids (2n = 6x=72). Many species are morphologically very similar to each other and species in series Piurana, and species boundaries and relationships are unresolved. This study is a replicated morphological study of a prior one by Castillo of germplasm accessions planted in the US. This study, conducted in a field station in Andean Peru, examined accessions from the prior study, and many more, by combining the germplasm resources of both the US and CIP genebanks; in total 117 accessions were examined in replicated trials. We analyzed out data by Stepwise Discriminant Analysis (SDA), Principal Components Analysis (PCA), Canonical Discriminant Analyses (CDA), and simple statistics (means, ranges, and standard deviations of individual character states). Support for species boundaries, like in the Castillo study, is mostly through a range of overlapping character states (polythetic support), and some species have no to little support. For example, S. colombianum (4x), S. moscopanum (6x), and perhaps S. orocense (4x), S. otites (4x), S. tundalomense (4x), S. lobbianum (4x), while all highly variable, cannot be reliably distinguished from each other. Also hard to distinguish from each other were S. laxissimum and S. santolallae (both 2x). Some species in series Piurana (S. irosinum, S. paucijugum, both 4x) are morphologically similar to those in series Conicibaccata, but are placed in series Piurana by prior molecular data. The taxonomic difficulty of species and series delimitations are likely caused by narrowly distributed local species evolving from more widespread species (pleisiospecies), hybridization, and allopolyploidy, which form questions for out on going molecular studies in the group.