Improving the Tomato Genome by breeding with wild tomatoes [2017]

20170613_165801_zpst2ebyfmd
Solanum peruvianum (wild tomato with desert tolerance)

So i haven’t written a blog post in some time. Sorry about that. It has been very hectic this year. That’s not to say that i’m completely dead. And despite my busyness and absence i am still dabbling a little bit in the garden and plant breeding scene. I didn’t have the time, energy, or space to work on my purple Indian Corn or Teosinte this year. I barely made room for beans, peas, tomatoes, and a row of watermelon.

The beans are my special four corners native beans which include, New Mexico Red Appaloosa (aka. Gila River bean), Anasazi, Zuni Gold, Rio Zape, and maybe a few others. The Peas are a large growout of my 17-23 different varieties of genetically unique and rare pea varieties, some of which are segregating crosses that i did two seasons ago. And tough i don’t have many pictures i will post one below of a purple podded umbellatum-type (aka. crown pea) where all the pods come out in a jumble all at once. To have a purple podded one of these is new and kind of cool. I hope to have a yellow and red-podded umbellatum-type pea someday. The watermelon are the result of mine and Joseph Lofthouse’s Watermelon Landrace project. Joseph Lofthouse seems to be world famous now for his widely successful landrace seed varieties and breeding techniques.

20170618_165017_zpstwhhddhz
Purple Podded Umbellatum Crown Pea

Anyway, back to the tomatoes. The Tomatoes are a brand new project and sort of an offshoot of one of Joseph’s new landrace breeding projects as well and a few other fellow collaborators and breeders as well. It all started when Joseph was working on wanting to convert tomatoes to a landrace like many of his other successful crops. But there are a number of problems with that and domestic tomatoes in general.

The first problem is that domestic tomatoes are entirely self pollinating and don’t outcross all that much and have tiny closed-up flowers. Another problem is that domestic tomato flowers are not very attractive to pollinators. And the third major problem is that domestic tomatoes went through several genetic bottleneck selection events when they were domesticated that they have a very narrow genetic base. This narrow genetic base means that 1. Most tomatoes are subject to easily succumbing to disease and 2. that when they do outcross there is not much variation anyway. An average bad-tasting disease susceptible red tomato that crosses with another average bad-tasting disease susceptible red tomato means that in the end all you really get is more of the same.

My interest in all of this starts with the basic fact that in my climate here in Northern Colorado with my soil (mostly a dry clayish sandy soil where mostly desert plants grow), and the high altitude with intense sunlight and UV and the dry wind that wicks moisture out of the ground means that most garden varieties of anything don’t do all that well here unless intensely babied. This applies most especially to tomatoes. Even worse when it comes to Heirloom tomatoes. Sure heirloom tomatoes generally taste better, but to have a tomatoe plant produce like ONE good tomato through a whole season… That’s a MAJOR FAILURE in my book.

There are lots of tomato freaks out there that try to tell me that here in Colorado i can grow ANY tomato variety and be successful. And while that might be true if i replaces all my soil with compost or potting mix and provided massive amounts of water, and started them all early and planted them all out perfectly then yes maybe that would be true. But that’s not what i want to do, not should i have to do that. I should be able to just start a tomato plant and plant it where i want and not have to worry about it all that much and have it produce a decent harvest (whatever that happens to be). And not have to worry about disease, or growing slow, or not being adapted to my soil or the intense UV light or whatever. That’s where all this plant breeding comes in.

The goal(s)

  • To breed a superior tomato variety that does well for me (in dry N. Colorado)
  • To increase the genetic diversity in the tomato genome by using wild tomatoes
  • To create or recreate a tomato that is highly attractive to pollinators
  • To create a population of tomatoes that are highly outcrossing
  • To create a tomato that i actually think tastes good and NOT like cardboard

.

OLYMPUS DIGITAL CAMERA
wild tomato seeds. photo courtesy of Joseph Lofthouse

This project is still in it’s early stage, but it is progressing nicely. On Joseph’s end he is having huge success by using wild tomatoes bred with domestic tomatoes that have large showy flowers with exerted stigmas and have lots of pollen available that make them attractive to bumblebees. He is using mostly Solanum habrochaites but is starting to branch out to other wild tomatoes as well. Others are working on breeding tomatoes that produce a good harvest in under 100 days from being direct seeded and that have frost tolerance.

On my end i am experimenting with as many wild tomatoes that i can. I am evaluating several accessions of wild Galapagos tomatoes which so far are not doing much. The S. habrochaites also are not doing much. The ones i am having excitement from are the Solanum peruvianum which have silvery leaves and desert tolerance (in the roots) and a F1 hybrid between a domestic tomato and Solanum pennellii which has a different form of desert tolerance (in the leaves). I am excited about these genetics since they seem to be growing very well in my garden. The largest of any of my tomatoes is this F1 hybrid of S. pennellii. It is HUGE!!

20170613_165811_zpswbxpmtcc
F1 hybrid between domestic tomato and Solanum pennellii
20170618_171140_zpsrcegtafh
Flowers of an F1 hybrid between domestic tomato and Solanum pennellii
20170613_165826_zpsx7ejhhv5
F2 cross of domestic tomato and Solanum habrochaites

A Teosinte Christmas in Colorado

So, i know I’ve blogged a bit about experimentally growing Teosinte in my post about growing prehistoric corn and also in my post about differences between teosinte species. Both posts have gotten quite a bit of traffic over the years and have brought people to my blog who are interested in Teosinte specifically.

For those of you who don’t know Teosinte is a progenitor to modern Corn (Also known as Maize), which is still able to interbreed with Corn. Some teosinte is annual, while others are perennial (or maybe bi-annual). There are many people who are interested in breeding perennial teosinte with corn to make perennial or bi-annual corn.

The major problem with trying to grow Teosinte in a moderate climate as here in Colorado in the United States is that it is adapted to grow in the climate of mexico and our growing season just isn’t really long enough. Even more so since Teosinte is day-length sensitive and does not even start to tassel, silk, and pollinate until the days get short and the sunlight shifts deeper into the red spectrum. By the time that happens here it is usually around August and often we get snow by September or October. Definitely not enough time for Teosinte or Corn seeds to mature and dry down for saving. …Or is it?!

Well, this year it just happened to turn out just barely long enough. I’m calling it my Christmas miracle! haha. I think it was a combination of it being a La Nina weather year with an unusually warm fall with no snow until here in December. But also with the fact that i dug up my clump of teosinte plants and put them in a pot in the garage. Though they were a bit unhappy in the garage and were touching the ceiling.

Still i was able to keep them in there long enough to hand pollinate them. But to be honest i thought i had again failed to get viable Teosinte seeds. But when the plants were dead i went out and happened to find some! Above is a picture of what i believe to be seeds of ‘Zea mexicana’ teosinte seeds.

If there is one moral of this story that you should take away it is this: Never give up even when everyone else thinks you are crazy or tell you that what you believe is impossible. I learned this in gardening from my friend Joseph Lofthouse of Utah. He has had success with so many of his unusual crops that no one else in his valley of Utah is able to grow. He often starts with many varieties of a plant as possible and grows as many as he can. Often more than 90% of them die or fail to produce seeds. But he only needs a few that do. Once he gets seeds he can start to effort to plant them year after year and adapt them to his climate. If they still fail to thrive he lets them die or culls them off himself. But he has a variety of unusual crops, such as Landrace Watermelon adapted to Utah (and by extension Colorado), Landrace Cantaloupe, Landrace inter-species hybrid squashes, Tomatoes that are self-incompatible and are highly attractive to bees (modern tomatoes are not at all and are highly inbred), and more.

 

On the left here is a photo of one small cob of a teosinte hybrid (zea diploperennis-corn hybrid from the USDA) pollinated with what i believe to be flour or field corn pollen. On the right is the same teosinte-corn hybrid cob line but i believe this one was self pollinated with its own pollen. It seems to have popcorn heritage as the seeds show popcorn / flint corn characteristics.

OLYMPUS DIGITAL CAMERA

Here is another strain of day-length neutral teosinte (decended from Zea mexicana) that a collaborator Joseph Lofthouse of Utah is growing and having success with. I believe he got the seed originally from NativeseedsSEARCH in Arizona. He decided to test if it makes good popcorn.

dscf7711_zpsti7nay2v

Here is my Teosinte clump in the summer of 2016.

dscf7334_zpsw6z4l9wi

Here is the same spot with snow on it now in winter.

If you’d like to follow the discussion about growing teosinte in places it is not normally supposed to grow (or other unusual crops) then visit the Alan Bishop Homegrown Goodness plant breeding forum here!