Thought I would share some current results of the micro-tomato breeding from this summer. Remember, the idea is to create new varieties that do well in small pots. I’ve been working on two crosses predominantly this summer and have gotten them through to F3 plants (three generations past the original cross), that are just now setting fruit.
Let’s take a look at one of the crosses (Chibikko x Green Zebra) in the F2 generation from earlier this summer. The F2 is the first generation where we should see different traits. As expected, I have a mix of plant types and fruit characteristics. The two types of plant are determinate and indeterminate. Determinate plants have shoots that end in flower trusses and then stop growing from that point. Determinate plants are often desirable if you want fruit all at one time, or in batches, for canning, sauce making etc. Many paste type (e.g. Roma) and commercial processing tomatoes are determinates. The determinate trait is controlled by the Self Pruning (SP) gene. Determinate is also nice in a micro-tomato so it stays even more compact. The trade-off is that you get lots of fruit all at once.
One of my favorite selections from this cross was a determinate plant that was loaded with fruit and got only 13″ tall. The fruit was light red and decent tasting.
The fruit characteristics are more complex genetically. Lots of variation here as well! My favorites were the striped red and orange (#2) and the black fruit (#10). Many of these plants were indeterminate and grow more like a typical dwarf and get maybe 5′ tall when planted in the ground and produce fruit continually.
From the above F2 fruit I saved a lot of seed. I planted five seeds from each of F2-2 and F2-1 in 1 gallon pots for a Fall crop. The resulting F3 plants and fruit will be assessed later in the month to decide which to keep, if any (assuming the blights and squirrels leave me any!) I will harvest the F4 seed from the good fruits for next year. This is the half-way point to genetically stable lines!
2014 is the year I plan to turn the backyard into an urban breeding farm! I hope to plant 10-15 of each of the good F4 lines in the ground and pots. Hope the neighbors like cherry tomatoes.
I have other crosses that are yielding some fun things. Updates later this month!