My Hybrid Tomato Experiment
A lot of people dismiss the idea of saving seeds from hybrid tomatoes because they don’t breed true. Me, I grow generations of them to see where they go. The results are interesting.
3rd generation Big Mama tomatoes showing a lot of genetic variation
I know a lot of people have never thought about what it means when seeds or plants are “F1” hybrids. But I, as an amateur botanist and all-around curious person, think the subject is fascinating.
The term “F1” means that the seeds (or plants) are the first generation of offspring from two genetically distinct parents. Generally, the parents are from stable lineages (i.e., the traits don’t vary from generation to generation) and crossbred to produce a hybrid that reliably inherits desirable traits from both parents. For example, disease resistance from one parent, and a compact growth habit from the other.
When you see “F1” on a seed package or plant label, you can rest assured the mature fruit is going to look like the picture on the label.
The deal is, though, if you collect your own seeds, the next generation (“F2”) of those plants does not reliably reflect the traits of both parents equally. Rather, through the magic of genetics, those next offspring tend to be more influenced by one grandparent or the other.
That’s why if you value reliability and predictable outcomes in your plants, you look for F1 hybrids. On the other hand, if you’re trying to improve upon a hybrid, or want to de-construct its lineage, or just want “see where it goes”, later generations can provide interesting insights.
De-constructing the Big Mama Hybrid Tomato
Generation One (F1) – Outstanding Results
One of the most impressive tomatoes I’ve run across in the past few years is Big Mama Hybrid.
A friend of mine gave me a packet of the seeds back in 2021, which I planted in a sort of experimental area of the vegetable garden in the spring of 2022. The results were outstanding.
Big Mama is an indeterminate paste tomato. The plants grew to be 6 feet tall, and between July and October produced loads of baseball-sized, dense, meaty red tomatoes perfect for sauces, slicing, and soups.
The fruit of the Big Mama hybrid tomato (first generation)
More importantly, there were no problems with disease, heat, cracking, scarring, blossom end rot, or many of the other issues you run into with tomatoes.
We jarred something on the order of five gallons (20 liters) of tomato sauce that year – about half of which was Big Mama. The results good enough that I saved the seeds from a few of those for planning next year.
Generation Two (F2) – Still Good
In the spring of 2023, I planted the Big Mama seeds I collected the previous year. I started them in the greenhouse in February and planted them in the west end of the vegetable garden. Like the first round in 2022, I made sure they were again well away from other tomatoes to limit the chances of cross-pollination.
As with the F1 seeds, the plants grew to be about six feet tall and they fruited over the same period between early July and October. Their productivity wasn’t quite the level it was the year before, but that may have been the weather as well (it was very cool in spring, and the summer was wetter than usual).
The tomatoes themselves were still baseball sized, oxheart-shaped, smooth skinned, firm, and dense. Again, no problems with disease or pests outside of a mouse or two that learned the fruit was quite tasty.
Along with the other tomatoes, we ended up saucing and jarring about 5 gallons again, although this time the Big Mama only represented about 1/3rd of the total.
Second generation of Big Mama tomatoes are still highly productive
Still, production was good enough that I saved some seeds from this generation to plant again the next year.
Generation Three (F3) – Starting To Vary
This year I once again planted six Big Mama plants I started in the greenhouse back in February. This time around, however, I stuck them in a center bed where they’d be in full south-southwest sun all day.
It’s mid-July now, and once again, the plants are in the 6 foot range, flowering consistently, and producing some of the first big tomatoes of the season (the Valentine grape tomatoes were the first to ripen back in late June).
What’s really interesting about this year’s fruit is the tomato forms are really starting to vary. One of the plants is still producing the familiar oxheart-shaped tomato, but two are now producing a much rounder, slicer style tomato, while the other three plants are producing mid-sized plum-style tomatoes.
What’s also interesting is that the oxheart and plum-shaped tomatoes are growing larger fruit in clusters of 2 or 3, while the round ones are growing in clusters of 4 – 6 fruits.
Regardless of their shape, they’re all still quite dense and meaty, and I’ve yet to have any real disease or pest problems – though one of the plum variations is showing some blossom end rot. It might be the soil in that particular spot needs some sweetening, but the round variants right next to it aren’t showing any.
Since I thoroughly mix and evenly distribute the soil in these beds at the beginning of the season, I’m thinking one part of Big Mama’s family is a plum tomato in the Roma family, which are known to be more susceptible to blossom end rot than other varieties.
Based on what I’m seeing, the other parentage is something in the cluster family, possibly a determinate processor-style tomato like Heinz, which is still meaty and dense but has smaller fruit than Big Mama.
Each of the Big Mama variations in gen 3 (F3)
What’s Next – Only Time Will Tell
Since we’re only halfway through the season, it’s really too early to tell what the final results will be. Maybe they’ll all be as productive over the same period as gen 1 and gen 2 of Big Mama. Then again, maybe the cluster variant will end up being determinants and peter out next month while the plums variants continue on their way (though with the blossom end rot issues).
All I can say right now is that they’re all producing quite heavily and the flavor is very good regardless of their shape. It’ll be interesting to see how they turn out at the end of the growing season, and even more interesting when we plant generation 4 (F4) next spring.
My fingers are crossed they stay productive and delicious regardless of the way they look.
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I’m in the UK and grew F2 from Crimson Crush a blight hesitant variety. Blight is a big problem in our wet summers! They all did well on that front. Some plants were potato leaved, some fruit plum shaped and some fruit dark shouldered – all very interesting. Not sure I’ll try F3 though.
I have a couple experiments — one tomato and one squash — that I ran out to F5 before they both turned into some super weird plants. The tomatoes, which began as 4th of July Hybrid (a cluster tomato) sort of devolved into a grape-sized fruit that was an aphid magnet. The squash, which began as a nice, compact Italian squash, turned into a weird pumpkin/green butternut shaped something that sprawled 60 feet in every direction (even with heavy cutting).
I guess there’s a reason heirloom are heirlooms!