Google Scholar finds

* Weese & Bohs, A Three-Gene Phylogeny of the Genus Solanum
(Solanaceae), Systematic Botany 32(2): 445-463 (2007)

at
URL:http://www.ingentaconnect.com/conten...00032/00000002
/art00013

but this is not accessible to me.

The most recent stuff I've seen is

* Bohs, Major Clades in Solanum based on ndhF Sequence Data

at
URL:http://www.nhm.ac.uk/resources/resea...cts/solanaceae
source/taxonomy/publications/Bohs2005MonSysBotMBG104.pdf
--
Stewart Robert Hinsley