Quote:
Originally Posted by jmsieglaff
I've read through a good portion of this thread and didn't see it exactly stated--but I certainly haven't read every word. If one were to cross a micro dwarf with a regular dwarf--I assume the F1 would be regular dwarf? Would the F2 segregate out at 25% for micro--or is more than 1 gene involved and it be a smaller percentage? I'm growing a micro dwarf this winter and if I like the flavor reasonably well, I may grow another one this summer to cross with a released dwarf project purple tomato for a fun little project.
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The basic idea of the micros is that they have two distinct dwarfing loci (d, 'dwarf'; sd, 'sun-dwarf'), while dwarfs have one dwarfing locus (d or sd). Other traits like sp ('self-pruning') and various other [unnamed] genes can be involved in producing a particular growth form.
I've been growing out F2s from a micro ("Tiny Tim") X regular (Roma) F1 and have found micros to be near the 1/16th (and dwarfs near the 6/16th) expected from the two-gene model. They have varied from upright to sprawling, but I haven't grown enough to estimate any ratios involved.
With your proposed cross, I would expect the F1s to be "dwarf" and a quarter of the F2s to be "micro". The micro-trait will then be fixed, but it will take the several more (to F8-9) generations to stabilize all/most of the other genetics that are segregating in the population.