Promiscuous Tomatoes

Mission Mountain X Lofthouse promiscuous fruity strain open cross hope

I am to a point with tomatoes where I have exserted strains (that is the female part of the flower sticks out where bees can get to it) I can put into crossing blocks. The height of this technology is exserted potato leafs because then I can find the hybrids with regular leafs in the seedlings.

I can do these crossing blocks before the varieties are perfected for traits like exsertion of the stigma- though it works best with the individuals whose female parts stick out the furthest.

So this year one of these crossing blocks was between some of my Mission Mountain potato leaf tomatoes and the regular leaf offspring of two individuals I liked from the 2021 grow out of Joseph’s promiscuous tomato projects one of which may have been from three plants Joseph selected in 2020 called S35, S36, and S37 for exceptionally fruity flavors. I liked it so much I called it “The One” The other one from where it was in the row was almost certainly from my savings of bicolor seeds from the 2020 grow out of the same project. It was weird producing mostly seedless tiny pumpkin shaped cherry tomatoes and I called it “little pumpkins”. The Mission Mountain tomatoes in the block included both Mission Mountain Sunrise or MMS and Mission Mountain Morning or MMM the main difference is I crossed MMS with Big Hill so it has larger tomatoes and better exsertion.

I also tried the cross as a hand cross but “The One” has difficult floral features to grab on to in some ways- the anther cones fall apart for instance. So that didn’t work.

In theory the cross should have happened though on its own. And a block like this last year with the arthropod resistance project was very productive.

So I’ve saved packets of MMM and The one’s fruity children from the block and their should be hybrids in there somewhere. I even have a few packets from the best of the MMM for exsertion of the stigma. Though generally MMM is better for this trait then MMS. Like Exserted Orange and Exserted Tiger before it MMM will require some selection to fully develop this trait- but I think it will be possible to tease out a more reliable version than MMS has because of the addition of Big Hill.

However last Sunday I decided to grab enough seed to direct seed and it is a mix of MMM and The One possibly with the other two as well. I was a little shy about what all I grabbed because I didn’t want a bucket full of MMS. Still that’s a lot of tomato seeds!

My ultimate goal with this is a fruitier and more exciting version of a Mission Mountain centric tomato.

Edit: for the potential of a 2022 cross between MMM and The One! I have almost exhausted all hope- but not completely. I didn’t see any regular leaves amongst the potato leaves. So now I have direct seeded almost all seed from the crossing block a grex of all possible parents and a grex of The One from all crossing blocks. If the intended cross happened we may yet find out when and if fruits form and have a bit of a half strength blue blush on a regular leaf cross.

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Debbie A
Hey, William, I didn’t understand everything you just posted, but I gather you’re pretty excited about it. Would it be ok to ask you to post a diagram of your crossing block? I would like to know how it’s done. Is it an orderly way of generating crosses between plants?

When you hand cross, are you using tools like forceps to open the flowers?

Are you direct seeding now (fall), or waiting until spring?

William S
See figure attached for an example of what this could look like in my six isolation gardens in 2023: Take two different tomato plants of two different varieties and plant them about one foot or less from each other with one of those varieties but ideally both having exserted stigmas. Then isolate by 150 feet from any other tomato varieties. You can repeat if you have more than two plants. Just intermix the two varieties. The technology here if you call it that is selection for exsertion, selection for potato leaf- because a potato leaf mother crossed with a regular leaf father will produce regular leaf offspring, and spacing- sufficient to minimize the likelihood of an unintended tomato cross. I think it is a super orderly way to generate crosses. See in the diagram how I use MMM or Mission Mountain Morning as the base for each of the six crosses? It is the potato leaf offspring of Big Hill and Mission Mountain Sunrise. I’ll use plants descended from the most exserted individuals of 2022 in 2023.

I do indeed use botanical forceps to make my crosses. I also use a pollination tool that vibrates the flower and a black plastic spoon that came with a different pollination tool that has since been replaced.
Now to make a hand cross you do what this gardening in Norway youtuber does:

He has shaky hands and mine are still steady, I think this illustrates nicely that we can keep doing this work for a long time in our lives!

You can also transplant a whole anther cone in some instances- which is something Walt Pickens told us about on Alan Bishop’s old Homegrown Goodness forum . Works good with using the fragile stigma currant tomatoes as a pollen parent. I used it this year to cross two currant tomato varieties into the Mission Mountain tomato project.

I direct seed in the spring. I plant about 20 days before expected last frost because in what I now know is a rare occurrence it is possible for warm weather to allow germination about 10 days before the last frost and 10-day old seedlings are pretty good at surviving because they are so short. However, for unknown reasons volunteer rates are far lower than direct seeded success. This leads me to conclude that fall planted direct seeding success would be low. Though volunteer rates seem to be higher in some varieties. For instance, in 2021 I direct seeded a mix of promiscuous, Big Hill, and exserted tiger. In 2022 about five plants of exserted tiger volunteered- ET was almost entirely a product of direct seeding and volunteerism. Its ancestors both worked well direct seeded and its ancestor Amurski Tigr both volunteered and was direct seeded in 2017.

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Debbie A
After watching the hand cross video, I would probably encourage the bees to do the work for me! Do you have other species between the ‘islands’ of tomato pairs? Have you found that bees favor certain plants over tomatoes? Just wondering if there are plants to avoid so the bees won’t ignore the tomatoes.

William S
I have mostly grass that came with the property between gardens.

On the property there are several areas where I have intentionally planted pollinators gardens both within and between gardens. There is also a hill which still has much of the native flora and some naturalized flora and which still supports native pollinators.

I do not believe that this is a zero sum game where some other plant will outcompete tomatoes for pollinators. I think what will happen instead is that you will get more pollinators the more diverse food you feed them and the more food total you feed them.

Some pollinators researchers in California did a study and they basically found that the older and more diverse the garden the more species of native bees. The plants did not have to be solely native but they had to be flowers and diverse flowers.

My wife has a two year old interest in cut flower farming and seed growing. This has resulted in a only partially intentional pollinators garden that I think puts mine to shame. While the bees seem to be constantly working there, the massive increase in diverse floral resource has not threatened my crops pollination.

Four plants you should plant for bees in the western u.s. in my opinion are bee’s friend Phacelia tanacetifolia, Bee balm Monarda fistula, nettle leaved hyssop Agastache urticifolia, and common yarrow Achillea millifolium.

If you were to strategically plant a solid row of these plants in between your isolation blocks it would probably result in bees stopping and loading up on other pollens in between. This would probably result in less unwanted cross pollination between blocks.

I started a thread here on the OSSI forum to talk about the important link between gardening for pollinators and vegetable breeding especially this sort of vegetable breeding: Pollinators, Pollinator Gardening, including diverse bees and others

Emily S
I am so intrigued by the sound of those fruity flavored tomatoes Joseph Lofthouse has developed. I really want to try some.

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Tomato prebreeding for stigmas and styles that are exserted from the pollen cone


In 2017 when I was just getting started with tomato breeding. I read some things Alan Kapuler and Joseph Lofthouse had to say about an important trait in tomatoes.

This trait is a stigma that is exserted that is sticks out a bit from the anthers which in tomatoes usually form something called an anther cone. The cool thing about tomatoes like this is that they are more likely to cross.

In 2017 Joseph had been low on seed for his new tomato Big Hill so he didn’t send me that seed, but he did send me an enormous amount of variable tomato seed. So, I had about 70 kinds of tomatoes including Lofthouse landraces of an earlier version than current promiscuous lines. I searched through them looking for exserted stigmas. The best ones I found were on a variety bred by a physics teacher in New Mexico called Blue Ambrosia. 4 / 5 plants had stigmas that stuck way out. I bought a pollinator tool and grabbed pollen from just about everything I could and daubed it on those stigmas. Then I saved all the seed and grew it out again the next year and found hybrids. From that effort I ultimately ended up with a tomato called exserted tiger from a cross with Amurski Tigr. Tomato, Exserted Tiger – Snake River Seed Cooperative
I reselected it for that long exserted stigma. I did get more seed from Joseph and that included Big Hill in 2018 and seed in 2019 for the F2 of a cross with Big Hill and something orange- maybe a habrochaites hybrid? In another Lofthouse collaborators garden. I took that orange tomato, and I did the same thing with it- simultaneously that I did with exserted tiger.
Tomato, Exserted Orange – Snake River Seed Cooperative
I reselected the best F2 plant for exsertion and orange and the best F2 plant for exsertion and tiger stripes.

That same year I made another cross a potato leaf red in a Lofthouse landrace mix had a modestly exserted stigma and I daubed Blue Gold pollen on it from a Brad Gates tomato. The result was ultimately Mission Mountain Sunrise. In 2021 I had one with an awesome exserted stigma and because it was potato leaf and potato leaf is recessive, I knew all the regular leaf offspring were hybrids. I also made a deliberate cross on it. I crossed it with Big Hill. I even rushed to grow the F1 over the winter. Then after I saw all the hybrids from Mission Mountain Sunrise. I wondered if I had needed that Big Hill cross after all. Then they bloomed- no exsertion! I remembered that the potato leaf seedlings of unknown Lofthouse landrace red weren’t always exserted. Yep, the trait from that source is temperature dependent. The warm spring of 2021 led to exsertion and the cold spring of 2022 led to none. So, it turns out I needed that Big Hill cross after all- and I had a very favorite plant with the best exsertion from the F2 and potato leaves.

So where am I going with all this? This is a process called pre-breeding. I am breeding tomato plants for a trait. Now where I am at with this is I have four or five varieties in my garden with a good form of that trait and another group with lesser forms. The neat thing about this trait though is that it leads to outcrossing. So, I now have a set of tools potato leaves + exsertion that I can use to do isolated crossing blocks with a high degree of success and no manual crossing. Oh and because of the power of sharing tomato seed, you will soon have these tools in your garden as well. How soon? Well, I linked to two of them I released through Snake River Seed. The third will need a generation in an isolation block so I can grow enough seed to share. I call it Mission Mountain Morning.

Next year I am going to cross potato leaf seedlings of Mission Mountain Morning with Exserted Orange and Exserted Tiger. I am also going to search for crosses with by growing trays of Mission Mountain Morning from various crossing blocks and looking for regular leaf seedlings. Those attempted crosses include a fruity strain of Joseph’s promiscuous project. In 2021 that fruity strain had exserted stigmas and open anther cones- but they were more closed up in 2022- so maybe a bit weather dependent on that strain!

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Lowell M
Wow, this is awesome! Thank you for providing all this detailed information and links. I really, really appreciate it. I am looking forward to trying your two varieties in North Florida next year. We typically have a lot of issues with pests and some diseases here which I think could be minimized by having short, determinate tomatoes, and then the promiscuous genetics would also be helpful to further adaptation. Your breeding work is inspiring me to continue working with tomatoes.

William S
Solanum pimpinillifolium famously grows well in Florida. Like the variety called everglades. If I lived there I would cross it with my exserted lines even if I had to make the initial cross indoors. I can’t guarantee anything is determinate. Exserted tiger is indeterminate. Exserted orange could be either.

Lowell M
I will try that with pimpinillifolium next year. Thanks!

Gregg M
Great work William. I will continue to watch how this develops from afar.

Mission Mountain Tomato project

In my first year of tomato breeding 2017 several crosses happened. One of these was between a unknown land race mix pre-promiscuous project potato leaf exserted red from Joseph Loft house and a Brad gates bred blue bicolor named blue gold. After several generations this became something I called Mission Mountain Sunrise. A potato leaf bicolor with a blue blush and in a warm year decent exsertion. Potato leaves are extremely useful as a marker in breeding tomatoes because any regular leaf seedling is a cross with a regular leaf variety. Last year I crossed MMS x Big Hill. Big Hill has exsertion without so much of the tendency to become inserted in cold

Open Source Arthropod (insects and others) Resistant Tomatoes

Several years ago, I watched a YouTube video of a presentation by a researcher named John Snyder who had made some arthropod resistant tomatoes.

He crossed Solanum habrochaites accession LA2329 with known arthropod resistance to domestic tomatoes. I have had great luck with direct seeded tomatoes, but my collaborators Joseph Lofthouse and Andrew Barney had a lot of predations from an Arthropod pest- perhaps flea beetles. I thought maybe this could be a solution! So I requested some LA2329 from the Tomato Genomics Research Center (TGRC) they were kind enough to oblige, and I have been growing it for three years. This year I have promiscuous x LA2329 from last year’s crosses so next year will be the exciting F2 generation. Also, I think I have managed to make more crosses including Mission Mountain Morning x (promiscuous x LA2329), Big Hill x LA2329, MMM x LA2329, and some new promiscuous x LA2329.

It will be a while before this project actually tastes good though! I think it was about the seventh generation of the original project that did.

Oh, I am also working on a Solanum galapagense version with accession LA1410.


Ray S
That’s very intetesting. I knew S. habrochaites imparted off flavours initially but 7 years! Wow! Oh well, it will be worth it I think to have some wild genes in there.

William S
The initial seven generations took less then seven years with 2 generations a year some in Josephs home and some with a California collaborator. Some really elite tomatoes appeared as early as 2019 and Joseph shared seeds of those in 2020. So I’ve been growing the elites for three years. There are still off flavors though. Also extra good flavors maybe from the penellii. I sometimes can’t believe I have gone back to the drawing board with a new habrochaites line. Also this LA2329 isn’t the only habrochaites line I am working with! Working with the extremely unpalatable hard green when ripe species tomatoes is definitely not the easiest tomato breeding.

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I found out today for sure that the TGRC MTA does not apply to derivatives. That means that if I can cross them, I can give them away without an MTA. So my LA2329 crosses are not something I need to worry about MTA’s on anymore since they are derivatives now.


Got my 2023 starts going for the promiscuous tomato project, also a few wildlings to try for some fun flavors there

a couple of the wildlings look very interesting almost like they could be dwarfs which would be very cool

MMM x The One! is still only a hope! The crossing block has so far not produced a cross! Wondering about direct seeding it in again in 2023!?!

ok, so the goal of this is still to save seed from any plants with stigma’s that hang out past the rest of the flower? Are we looking at flavor or growing habits at all yet? Do we just cull stuff that isn’t? I’m only growing about 9 from the promiscuous mix, and about 15 wildlings (i assume i’m looking for fun flavors there)

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I would say the goal is up to you! If you like stigmas that stick out a bit for the occasional natural cross that is fine. If you like certain flavors that is fine too. If you don’t like those things but find something else that you do like that is also fine.

oh, i thought we were all trying to pick out the same things for the project, though I guess ya if we’re all just “doing our own thing” then it won’t matter.

I have thought of it a bit as a duality over the years. Searching for plants that you personally like is reasonable. Searching for plants that meet the goals that my friend Joseph set is also reasonable.

If we all looked only for the same things it would result in a narrowing of what may be possible. One of the explicit goals here is diversity- so saving and enjoying a fuller range of that diversity is possible!

It is reasonable to say “Oh I like this!” and it is also reasonable to say “Oh, I think my friend, or my group of friends might like this!” Also if you like something you find in a segregating plant population. It is likely that someone else will also like it.


Am I understanding correctly that “the one” is more likely to receive pollen in a random cross rather than the other way around? Also is it more likely to cross with pimpinellifolium than domestic varieties? I’m not at all skilled in hand pollinating tomatoes but thought I might try to cross it to my Mr. Stripy for sure and maybe some others too.

On a somewhat related note, I have a very odd-looking tomato that showed up in my cherry mix this year. There is a lot of pimpinellifolium in that mix, but this thing looks very different from anything I’ve seen before. I’ll post a picture later and see if you might have a guess what it is.


It seems possible that “The One” might be a better receiver than giver. Though I can’t currently verify that. I’ll be mixing strains that may have received with others and direct seeding them and there could be tells! If any prove crossed it will be very exciting!

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Wow, so much information, super informative. Thank you William for sharing sonmuch of your process and expertise!
I am new to growing promiscuous tomatoes (i love the whole concept!!) but have a few started to go along with the family’s favorite OP varieties and I noticed that the seedlings close up at night. Like their first 2 baby leaves (cotyledons?) fold upwards at night but during the day are behaving perfectly normal and assume a “T” shape. Has anyone else noticed that? I am super curious to see what happens once there are more leaves.

This was seed from the experimental farm network from the Promiscuous tomatp project

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Some of the ancestors of the Beautifully Promiscuous and Tasty Tomatoes project fold up at night. I suspect that the trait helps with frost/cold tolerance at high elevation when radiant cooling occurs.


Oh, that’s cool! Think that may be a trait to watch for in seedlings?

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