Let's follow the "lineage" of one of the more promising varieties, one that I selected for an named for my wife - "Dwarf Sweet Sue". So back in 2006, my friend Patrina, in Australia, decided to cross a relatively new, delicious heirloom type - Green Giant - with a historic dwarf variety, Golden Dwarf Champion. The cross took, creating a hybrid that Patrina named Sneezy. She sent seeds of Sneezy to me in early 2006, allowing me to grow it out that summer.
Sneezy was a nice hybrid - very vigorous, regular leaf indeterminate (as expected), producing medium sized, round bright yellow fruit with a delicious flavor. As expected, the hybrid showed the various dominant traits that should show up in a hybrid - regular leaf foliage (Green Giant is potato leaf), indeterminate growth, and yellow fruit midway in size between the two parents. I saved plenty of seed (considered the F2 generation) and sent them back to Patrina so she could distribute them and grow them out.
David Lockwood, one of Patrina's Dwarf Project volunteers, grew out a number of plants from the Sneezy F2 generation seed I sent during their summer of 2006/2007, and one of them he named Summertime Gold 3. His description was a dwarf growing, potato leaf plant producing "large pale yellow oblate fruit with a pink blush and good flavor". Patrina gathered seeds, now F3 generation, from all of her volunteers and sent them to me.
In the summer of 2007, I grew out many different Sneezy offspring from both Patrina and David - and one of them, from David's Summertime Gold 3 seed, was a winner. The fruit from the particular potato leaf dwarf plant was slightly variable in shape, from round to oblate, pale yellow with a pink blush on the bottom, in the 8 ounce range, with an outstanding sweet but complex flavor. I christened it Dwarf Sweet Sue (named after my wife - who, though not dwarf in stature, is very sweet!), saved seeds, now at the F4 generation, and sent them off to Patrina for further testing -I also sent it to a Tomatoville friend, Michael, in Texas, whose growing season essentially echoes the timing of the Australian grow outs.
David and Michael both had good luck with Dwarf Sweet Sue, liked it very much and had results consistent with my selection criteria in 2007. Seed was returned to me, but I now had two different seed lots to choose from and test out, to check how consistent the newly emerging variety was becoming.
In the summer of 2008, I grew two plants of each - from David's saved seed, and Michael's saved seed. I was now growing out the F5 generation, meaning that there should be more consistency, less variation, as stability of this new variety was approaching. I was delighted to find that all four plants yielded very similar results - all potato leaf dwarfs, all producing slightly variably shaped bright yellow fruits with the pink blush, all in the 6-10 ounce range, with exceptional flavor.
So seeds (now F6 generation) were saved and sent back to Patrina, who got them back to David. He grew them out, they met the description criteria we set for Dwarf Sweet Sue, and they were returned to me as F7 generation seeds. Last summer, 2009, I grew them out and found them to grow as I hoped, and my saved seed from those fruit were now at the F8 generation. At this point, Dwarf Sweet Sue can be considered as a new variety.
So, this is a good little "case history" of how we are developing new varieties in the Dwarf Project. This is one of the varieties we hope to have in seed catalogs soon!
A few pictures of Dwarf Sweet Sue