A large Black Plum
Hmmm....I have in my inventory of breeding lines many that might fit into what you want. Since you are not far from Luther Burbank's old breeding site near Santa Rosa....I might be interested in helping you find a segregating population which would touch the main key words;
- Large
- Black
Plum
It would take me a week to look into the pedigree info of about one hundred lines that may, or may not, fill your specs.
Santa Rosa, (Forestville) and I suppose you are about 10 miles away, should be a fairly mild climate compared to Bakersfield to grow tomatoes. What is you window of opportunity for sowing seed? Or better yet...direct seeding in the garden?
I am test marketing many blacks this year, but I need to add those to this list at
http://newworldcrops.com/wp/tag/tomatoes/
Tom Wagner