Author Topic: General Tomato Breeding  (Read 6634 times)

joseph

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General Tomato Breeding
« on: 2015-July-01 11:53:08 AM »
Over the past few years I have been working on a few tomato breeding/selection projects.

I started out in 2009 and 2010 by trialling hundreds of varieties of heirloom and modern hybrid tomatoes: Looking for anything at all that would produce fruit in my garden before frost. Most of them were spectacular failures! Brandywines and beefsteaks self-eliminated very quickly. I don't like providing the labor to pick cherry tomatoes, so they were mostly culled except for yellow pear and Sungold. I was mostly saving seed as bulk lots. Any variety that produced well got dumped into a common fermentation, and mixed with everything else. I did a little bit of selection for frost/cold, because about 10% to 50% of my plants get killed by frost every year, so the most susceptible got eliminated.

In the 2013 growing season I did a  frost/cold tolerant trial in collaboration with Darrel Jones. He provided seeds from varieties that are known for cold or frost tolerance. I found one variety Jagodka, which is quite susceptible to frost, but it grows robustly and fruits quickly in spite of the cool nights. It ripens every fruit in spite of the short season.

One thing that we learned from the trial, is that I should be focusing on determinate tomatoes because they are more productive earlier in the season. I suppose that my plants had already shown me that, because my bulk seed had ended up being mostly determinate varieties. In the bulk seed collection this fall, I'm intending to do careful screening to only select for determinate plants.

I do a little bit of frost tolerance testing each year. One of these years after I get some of the other breeding projects further along, I'm intending to make some crosses to screen for better frost resistance.  I grew a flat of tomatoes this year that survived a two day long snowstorm without visible damage. Many plants had already been culled from the flat due to previous radiant freeze damage.

Another thing that I noticed during the frost/cold tolerance trial, is that the two varieties that were the most productive were also highly attractive to bumblebees. I'm speculating that they set fruit earlier and more reliably because they were being better pollinated. The flowers shed a dust cloud of pollen when jostled. So that triggered the idea for the breeding project I expect to work on for the next few years: Developing a landrace of tomatoes that are promiscuously pollinating. I'm hoping that will allow me to spin the genetic roulette wheel more frequently in my garden, and lead to quicker development of tomato varieties that really thrive in this area. It will also lead to my garden being full of hybrid vigor. I won't have to suffer through the inbreeding depression that seems so commonplace among the heirlooms that I have grown.

Part of my motivation for pursuing promiscuously pollinating tomatoes is that I think they will do a better job of acclimating to late blight. Rather than throwing one highly inbred variety at the problem, I intend to throw a field of tomatoes at the problem, with each plant being genetically unique and diverse. Then those plants that are most tolerant can share genes readily with each other. It might be many different traits working together that provides the best tolerance. And not just a single tolerance gene. To further this project, I am collecting wild tomato genes, and crosses with wild tomatoes. This year I'm mostly expecting to grow seed, so that I can have gobs to sacrifice to testing.

Last summer I made a few hybrid crosses between Jagodka and varieties with open flower structures. I grew out the seed over the winter and collected F2 seed this spring. The final variety to produce seed is ripening now in plenty of time to grow it out this year. The other two crosses already have F2 plants growing. Some of the crosses were with determinate mates. Some were indeterminate. This summer I intend to screen for determinant plants with open flower structures.

Last fall at the farmer's market, a lady asked me about the taste of my tomatoes. I finally had to confess: "My tomatoes taste horrid". I decided after tasting lots of gaggy tomatoes that I like yellow and orange tomatoes better than red tomatoes. Therefore this spring I started another breeding project to develop tomatoes that are pleasing to my taste buds. I expect that they will end up being orange or yellow. I'm expecting that I will mostly use the orange/yellow tomatoes that I planted this spring as pollen donors to some of the F2 plants -- with determinate growth and loose/open flowers  -- from the promiscuous pollination project.

One of the F2 Hybrid tomatoes is a cross: [a yellow/red indeterminate beefsteak with open flowers X a determinate pollen donor], [Hillbilly X Jagodka]. Perhaps I'll be able to find what I'm looking for in one of the offspring: yellow/orange fruit, open flowers, determinate plants.

If I'm interpreting what I'm seeing properly, it looks like:

Yellow fruit is recessive
Open flowers is recessive.
Determinate vines is recessive.

I love working with recessive genes, because once I isolate a phenotype, then it is fixed until the plant cross pollinates with something that doesn't carry the recessive gene.

joseph

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Re: General Tomato Breeding
« Reply #1 on: 2015-August-29 11:41:16 PM »
Here's examples of some of the seeds I am saving this week:

Descended From Sungold-1


Descended From Sungold-2


Descended From Sungold-3


Descended From Sungold-4


None of the Descended from Sungold plants has the taste that the F1 hybrid is famous for.

F2:[DX52-12 X Jagodka]-1


F2:[DX52-12 X Jagodka]-2



F2:[DX52-12 X Jagodka]-4



F2:[DX52-12 X Jagodka]-5


F2:[DX52-12 X Jagodka]-6



F2:[DX52-12 X Jagodka]-7


F2:[DX52-12 X Jagodka]-10. This plant would have been culled already, except that I numbered the plants after the first culling, and it would mess up my numbering scheme to cull it now.



F2:[DX52-12 X Jagodka]-12



F2:[DX52-12 X Jagodka]-14


F2:[DX52-12 X Jagodka]-19



F2:[DX52-12 X Jagodka]-20


F2:[DX52-12 X Jagodka]-21


F2:[DX52-12 X Jagodka]-24


F2:[DX52-12 X Jagodka]-26


Segregating Hybrid of some sort or other. It has a sibling which is indeterminate.
Large Yellow Determinate:


The Wild Crosses were made by a collaborator. They are F2 or later. Some of them were spectacularly unsuited to my garden. None of them thrived here, but some of them produced a few fruits. Flea beetles were particularly troubling to them. The flowers were all tiny and industrialized types.

Wild Cross-10. Orange Indeterminate Cherry. This is a great tasting tomato. The gel sack around the seeds is green.


Wild Cross-5: Indeterminate. This is a great tasting tomato. The gel sack around the seeds is green.


Wild Cross-8. Determinate. ~18" vines


My tomato seed saving table...

keen101

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Re: General Tomato Breeding
« Reply #2 on: 2016-February-22 02:58:38 PM »
Curious to know how much better DXX-M fared than the Utah cambell's tomato it decended from. Have you tried crossing this line with HX-9 hillbilly-Jagodka line?
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joseph

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Re: General Tomato Breeding
« Reply #3 on: 2016-February-23 01:32:30 PM »
Curious to know how much better DXX-M fared than the Utah cambell's tomato it decended from. Have you tried crossing this line with HX-9 hillbilly-Jagodka line?

DX52-12 was developed for the next valley over from mine, which is a lower elevation and averages a 4 week longer frost free growing season. So DX52-12 is a bit long season for my garden.

The F2 hybrids fared well. They retained the trait of holding their fruits up off the ground when grown sprawling without cages. Fruit size was smaller than DX52-12, but larger than Jagodka. Days to maturity was much quicker. So overall, I am very pleased with the cross.

I haven't yet made any (successful) crosses using DXX-M as a parent. If I find any with open flowers this growing season, I expect to attempt cross pollinations with HX-9.

keen101

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Re: General Tomato Breeding
« Reply #4 on: 2016-February-23 02:47:33 PM »
DX52-12 was developed for the next valley over from mine, which is a lower elevation and averages a 4 week longer frost free growing season. So DX52-12 is a bit long season for my garden.

The F2 hybrids fared well. They retained the trait of holding their fruits up off the ground when grown sprawling without cages. Fruit size was smaller than DX52-12, but larger than Jagodka. Days to maturity was much quicker. So overall, I am very pleased with the cross.

I haven't yet made any (successful) crosses using DXX-M as a parent. If I find any with open flowers this growing season, I expect to attempt cross pollinations with HX-9.

Sounds great. Those 2 (and hopefully 3) lines are the ones i'm the most interested in. So i will be watching them excitedly. I'm going to attempt tomato trials this year. Heres hoping it goes well. Im hoping i'll find something to contribute to your project as i'm interested in tomatoes that are promiscuous, attractive to pollinators, and adapted to my area as well.

I will do my best to watch for differences in flower structure and those more visited by pollinators. Hoping to find any that have uv colors as well.

I think its really cool that your tomatoes have the upright growth without cages. How common is that trait?
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Michael

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Re: General Tomato Breeding
« Reply #5 on: 2016-February-24 01:43:27 PM »
I haven't looked too much at the dwarf tomato project, but I gather they are breeding for plants under four or so feet tall and sturdy enough to stand more or less on their own.

Last year I kept saying everyday that I would definitely stake the tomatoes tomorrow. It was a fairly unruly mess, i had to step all over them, but overall turned out better than I feared it would.  The critters nibbled their fair share, but a decent percentage of the fruit was high enough off the ground to escape unscathed.  As a side benefit I know my seed for this year can withstand me walking all over them.  I do have seed for one dwarf tomato, it might be worth crossing that with my core populations and seeing where that goes.

Carol_A

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Re: General Tomato Breeding
« Reply #6 on: 2016-April-22 08:15:16 AM »
Joseph, have your tomatoes had to deal with late blight in your growing area?  Here in upstate New York (zone 5a) it has become quite an challenge for tomato growers, some years worse than others.  I'll be growing some of your tomatoes this year.  I'll let you know how they do in that respect.

joseph

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Re: General Tomato Breeding
« Reply #7 on: 2016-April-22 09:08:08 AM »
Carol_A: I think that I don't have late blight in my garden. I'll be interested in hearing about how my tomatoes do in your area.

Late Blight resistance is on my list of things to add to my tomatoes. I expect that will be best done after I get them promiscuously pollinating. That way, they can essentially become self-breeding machines. By constantly shuffling the genetics, it will make it much easier to find varieties that are resistant to late blight.  I expect that the selection for blight tolerance will have to be done in collaboration with growers in areas where late blight is a problem. So if you find any plants that are particularly resistant to late blight, I'd appreciate getting some seeds back.

Carol_A

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Re: General Tomato Breeding
« Reply #8 on: 2016-April-23 06:03:57 PM »
Joseph, I'll let you know how your varieties do.  I'm growing HX-9, DXX-M and Short Season Landrace, along with Legend (supposed to be resistant to late blight, bred in Oregon) and several other varieties.  Late blight is hitting almost every year here although sometimes it only gets bad later in the season, so it should be a good test.