D. Jagatheeswari, Cytological Investigation of Brazilian Nightshade (Solanum seaforthianam Andr.), Volume 15, International Letters of Natural Sciences (Volume 15)
https://www.scipress.com/ILNS.15.44
Abstract:
    Solanum genus namely Solanum seaforthianum Andr. belongs to the Solanaceae family, and comprises only dioeciously species. These plants are distributed between 29º and 40º south. All species of this genus are diploid with chromosome numbers of 2n = 24, 28 and 30. According to literature, the basic chromosome number in this genus is x = 12, 14 and 15. Solanum genus with a chromosome complement of 2n = 30 has a symmetric karyotype with a median and sub median centromere position. Because ancestral species have a symmetric karyotype, it seems that x = 12 is the initial basic chromosome number in this genus and the x = 14 and x = 15 derived from x = 12. So it seems that diploid phenomena played an important role in evolution and speciation
Keywords:
    Brazilian Night Shade, Chromosome Study, Cytological Investigation, <i>Solanum seaforthianum</i>, <i>Solanum</i> Species