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Title: A Replicated Morphological Study in Peru of Solanum Series Conicibaccata

Author
item FAJARDO, DIEGO - UW MADISON HORT DEPT
item SALAS, ALBERTO - INTL POTATO CTR LIMA PERU
item Spooner, David

Submitted to: Systematic Botany
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/15/2007
Publication Date: 1/8/2008
Citation: Fajardo, D., Salas, A., Spooner, D.M. 2008. A Replicated Morphological Study in Peru of Solanum Series Conicibaccata. Systematic Botany. 33(1)183-192.

Interpretive Summary: There are about 200 species of wild potatoes widely distributed throughout the Americas from the southwestern United States south to Argentina, Chile, and Uruguay. Many of these species are very similar to each other and they may not all be worthy of recognition as valid species. This study studies the validity of recognizing species for a group of 40 of these wild potatoes, technically known Solanum series Conicibaccata. They grow from southern Mexico to central Bolivia. It studies their species status by using the overall form of the plant (morphological data) from an area in the central Peruvian Andes, and compares these data to a prior study of the group from the United States. Both the US and Peruvian studies can distinguish groups of species that are diploid (two sets of chromosomes) from polyploids (multiple sets of chromosomes), but many species within these chromosome groups are difficult to recognize. We conclude that there likely are fewer species in series Conicibaccata. Because species names are used to make inferences on their use, as in potato breeding programs, this study helps us to make better inferences about the useful traits of this species.

Technical Abstract: Solanum series Conicibaccata is composed of about 40 wild potato (sect. Petota) species distributed from central Mexico south to Bolivia. It forms the second largest series in section Petota. It contains diploids (2n=2x=24), tetraploids (2n=4x=48) and hexaploids (2n = 6x=72). Many species are morphologically similar to each other and to species in series Piurana. Species boundaries and series relationships are unresolved. This study, conducted in an upland field station in Andean central Peru, is a replicated study of one conducted in the US, but is larger in that it combines germplasm from genebanks in Peru and the US. In total, 117 accessions were examined of xx species in series Conicibaccata and phenetically similar species in series Piurana. Multivariate analyses are concordant with US data by suggesting that many of the species in series Conicibaccata are conspecific, and that some of the species are related to those in series Piurana. For example, some northern South American polyploid species like S. colombianum, S. moscopanum, S. orocense, S. otites, S. tundalomense, and S. lobbianum, while all highly variable, cannot be distinguished reliably among each other. Even those fewer species that are supported can be defined only by multiple character states, few of which are species-specific (polythetic support). Preliminary data suggest that the taxonomic difficulty of the species and series delimitations are allopolyploids, the focus of our continuing molecular research.