Speed Breeding tomatoes 4 generations a year?

[William S.]

I just picked the first two tomatoes off my winter generation of F1 tomato after about 150 days. Conditions were not optimal I bet a much faster outcome could be possible with better conditions.

I was thinking about maybe planting another plant or two and was doing the math. The shortest season tomato I know of Sweet Cherriette is 35 DTM but that is after about a full 8 weeks of growing before transplant or about 91 days from seed to ripe tomato. That would mean that if I planted Sweet Cherriette now I would be looking at the first few days of April before I got a ripe fruit except that I am almost certain it would be sub optimal conditions and take a little longer.

However with optimal conditions and with certain genetics I bet you could do seed to ripe fruit every 90 days or about every three months.

Other ways to speed things up- dissect out the embryo at minimum viability and start it in tissue culture.

If you did let the seed ripen you could chemically clean it so no fermentation time.

Rather than dry the seed you could plant it immediately.

[Steph S]

I grew a micro called Red Dwarf and got ripe fruit 88 days from seed in the house.
If you wanted to breed micros and select for the in-house environment, I think you could do at least 3 gen in a year, assuming you had enough space for enough plants to make your selections.  That gives time for competing fruit to ripen and be assessed.
The only way to do four, you would have to be breeding for earliness alone, so that the first seed from the first tomato was the one you wanted to grow forward over all others.

[William S.]

Yeah, to do four you would need to have everything you were working with down to about 90 days from seed to ripe fruit. I think it would be really fun though for working with students to have more diversity in that category.

Some or the micro dwarfs I've been working with including Pinnochio and Lizzano? F2-3 seem about the same as sweet cherriette. All three red and boring though.

Have a couple other micro dwarfs to play with for 2022.

I have older plants of MMS x BH F1, Aztek, and a not yet blooming plant of Solanum galapagense and four pots with sweet cherriette that isn't close to blooming yet. Hope to get some hybrids though.
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[Steph S]

Lots of cool work going on with micro toms:
https://www.tomato-talk.com/forum/the-micro-tomato-diversity-project

[William S.]

I grew three microtomatoes last year then of those I am growing Aztek again and I think I've made a successful cross (MMS x BH F1) x Aztek fruits are just starting to swell. I think the mothers parentage has some potential for shortness of season as MMS is unknown Lofthouse land race potato leaf x Blue Gold and BH is Jagodka x Hillbilly and Aztek seems pretty fast as well.

Would be nice to get something like Aztek x Sweet Cherriette going while I have these plants as well. Got to wait for blooms though.

I did just notice the tiniest of buds on LA1410 Solanum galapagense. Now that accession would be fun to cross with just about anything. It has sort of orange hairball fruits. So hopefully it will bloom and I'll get some crosses started with it and these other three Aztek, Sweet Cherriette and the MMS x BH F1.

[Andrew Barney]

An interesting idea. I like the idea of combining 35 day tomato plus early embryo planting. You should teach us how to do embryo rescue and make our own culture media someday. Perhaps an open source breeding youtube series?

Anyway, but don't dwarf and micro plants grow slower? In peas, dwarf plants sometimes take longer to flower and produce fruit and have shorter roots.

[William S.]

Don't know if they grow slower. Krainy Sever, Lizzano? F2-F3, Pinnochio, and Aztec are all early dwarfs. So while they may be smaller plants they produce early enough.

I don't normally make my own media when I do plant tissue culture and video isn't a platform I am currently ready to tackle. In fact I would advise buying media even though many of us are technically capable of mixing tissue culture medium it greatly simplifies life to buy it premixed and tested. Not that I have gotten any tissue culture done in recent years! 

[Greenie DeS]

Steph, that's a great resource for a winter hobby. Looks like folks are just beginning to do some fun things with micros over there.

I have roughly 170 days between first frost and time to plant the first peppers and start using up my lights, 200 days between first frost and tomato planting time. Two in-house generations per year when the equipment isn't doing anything else would seem very doable here. I wonder if there's a benefit to throwing the 3rd generation outside somewhere to maintain some tolerance to that environment?

[Steph S]

I don't see any reason not to throw another generation outdoors.  You'd have F7 in your third year, and plenty of indoor gens to select for indoor critical features if they had mixed traits in something critical.  Ability to grow in the dark  that's what I look for, for a winter indoor tomato.  Selfing is critical too.   You might even pick up on something useful outdoors that might not be tested indoors, such as resistance to aphids.   Can't beat indoor plants that aphids will not colonize ever!
I was growing the Red Dwarf for a bite, didn't do any crosses but I did put the potted plant outdoors during the summer.  It lost all its leaves while ripening fruit, and then after being cut back a bit it returned and greened up and set another crop.
One thing about micros they have really tiny flowers.  The operation of emasculating has got to be difficult.  It would be easier to use the non-micro parent as mother plant.  I figure either determinate or dwarf would be a bit of a shortcut to recover the micro habit.  complex genetics in that, but easy to select that early, I guess.