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Solanum section Petota has been the subject of intensive taxonomic work since the description of the cultivated potato in 1753. In total, there are 494 epithets for wild taxa and 626 epithets for cultivated taxa. Different taxonomists applied various taxonomic philosophies and species concepts to the section. Hypotheses of the number of species and their interrelationships have differed greatly among authors. A taxonomic treatment of section Petota by Jack Hawkes in 1990 recognized 228 wild species and seven cultivated species, divided into 21 taxonomic series. In 2014 Spooner and collaborators more than halved this number to 107 wild species and four cultivated species, partitioned into four clades; not using series. The purpose of this paper is to provide a retrospective of the methods and philosophies that have resulted in this drastic decrease in the number of species and their infrasectional classification. [ABSTRACT FROM AUTHOR]

Wild potato ( Solanum L. sect. Petota Dumort.) species contain diploids (2 n = 2 x = 24) to hexaploids (2 n = 6 x = 72). J.G. Hawkes classified all hexaploid Mexican species in series Demissa Bukasov and, according to a classic five-genome hypothesis of M. Matsubayashi in 1991, all members of series Demissa are allopolyploids. We investigated the genome composition of members of Hawkes's series Demissa with genomic in situ hybridization (GISH), using labeled DNA of their putative progenitors having diploid AA, BB, or PP genome species or with DNA of tetraploid species having AABB or AAAaAa genomes. GISH analyses support S. hougasii Correll as an allopolyploid with one AA component genome and another BB component genome. Our results also indicate that the third genome of S. hougasii is more closely related to P or a P genome-related species. Solanum demissum Lindl., in contrast, has all three chromosome sets related to the basic A genome, similar to the GISH results of polyploid species of series Acaulia Juz. Our results support a more recent taxonomic division of the Mexican hexaploid species into two groups: the allopolyploid Iopetala group containing S. hougasii, and an autopolyploid Acaulia group containing S. demissum with South American species S. acaule Bitter and S. albicans (Ochoa) Ochoa. [ABSTRACT FROM AUTHOR]

The article focuses on the revision of the Solanum medians Complex (Solanum section Petota) which are widely distributed along the coastal lomas and up the western slopes of the Andes Mountains from central Peru and northern Chile. Research shows that its fertile diploid and sterile triploid cytotypes are common and believed to be associated with morphological variants. It was found that so much overlap of their taxonomy is impractical to use morphology for reliable identifications.

The article presents the morphometric study of species boundaries of the wild potato Solanum series Piurana (Solanaceae) and putatively related species from seven other series in Solanum section Petota in Peru. The morphological similarity of its constituent species has led to conflicting taxonomic treatments. Solanum series Piurana's limits and validity of constituent species are unresolved. Among its other series are Conicibaccata, Cuneoalata, Ingifolia, Megistacroloba and Simplicissima.

Solanum sect. Petota (tuber-bearing wild and cultivated potatoes) are a group of approximately 190 wild species distributed throughout the Americas from the southwestern United States south to Argentina, Chile, and Uruguay. Solanum series Conicibaccata are a group of approximately 40 species within sect. Petota, distributed from central Mexico to central Bolivia, composed of diploids (2n = 2x = 24), tetraploids (2n = 4x = 48) and hexaploids (2n = 6x = 64); the polyploids are thought to be polysomic polyploids. This study initially was designed to address species boundaries of the four Mexican and Central American species of series Conicibaccata with AFLP data with the addition of first germplasm collections of one of these four species, Solanum woodsonii, as a follow-up to prior morphological, chloroplast DNA, and RAPD studies; and additional species of series Conicibaccata from South America. AFLP data from 12 primer combinations (1722 polymorphic bands) are unable to distinguish polyploid species long thought to be distinct. The data suggest a complex reticulate history of the tetraploids or the need for a broad downward reevaluation of the number of species in series Conicibaccata, a trend seen in other series of sect. Petota. Separately, through flow cytometry, we report the first ploidy level of S. woodsonii, as tetraploid (2n = 48). [ABSTRACT FROM AUTHOR]

Morphological data and single- to low-copy nuclear DNA restriction enzyme site data were used to test subspecies circumscriptions of Solanum bulbocastanum and S. cardiophyllum. A prior chloroplast DNA analysis showed these species to be part of two main clades: 1. S. bulbocastanum subsp. bulbocastanum, S. bulbocastanum subsp. dolichophyllum, S. bulbocastanum subsp. partitum, S. cardiophyllum subsp. cardiophyllum and S. cardiophyllum subsp. lanceolatum, and 2. S. cardiophyllum subsp. ehrenbergii and other Mexican diploid species. The nuclear DNA and morphological data showed S. cardiophyllum subsp. ehrenbergii to be slightly distinguishable from the other subspecies of S. cardiophyllum, and do not support the distinction of subspecies within either species. These data add to a growing body of evidence that there are too many wild potato taxa recognized. [ABSTRACT FROM AUTHOR]