http://www.ncbi.nlm.nih.gov/pubmed/12589545
The abstract mentions the original 'dg' allele was discovered in the 1960s-era commercial variety "Manapal".
The variety seems to be available :
http://www.reimerseeds.com/manapal-tomato.aspx
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Correction: the 'dg' mutation was first found in "Manapal", but the variety is not characterized by the trait.
http://forums.gardenweb.com/forums/l...220447895.html