andyb
gardener
Posts: 179
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Post by andyb on Aug 23, 2015 0:39:38 GMT -5
I have a 1 1/2 year old son and he absolutely loves tomatoes, so I want to help him breed his own variety of tomato as he's growing up.
The core plan is to start with a four-way cross of very different varieties. Each year from the F2 on, I'll plant some number of plants and let him pick his favorite. Seeds from his favorite will be the F(x+1) generation.
That's all pretty simple and should work out just fine. I'll over-plant and cull any weak plants each year and will save backup seeds in the freezer in case of disaster.
The interesting bit, and the part of the plan I'd like feedback on, is that I'd like the final tomato to have late blight resistance. My plan for that is to start with a cross between a resistant variety and the selected F2 plant. Each following year, I'll grow out a separate batch of seeds, evaluate for resistance, and make crosses with the plant my son selects.
It should be like a normal back-crossing project to introgress disease resistances to a variety, but done at the same time as breeding the variety itself. By doing it this way I can keep the basic project really simple and always keep my son's favorite tomato each year without having to worry about genetic drag from the resistant tomato. Shouldn't take too much extra space since all I care about is getting a tomato or two for seed while evaluating disease resistance.
What do you think?
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Post by templeton on Aug 23, 2015 2:47:41 GMT -5
Andy, sounds like a great project. My limited experience with tomatoes is that they jump around a fair bit generation to generation, so expecting the same desirable traits to show up in following generations might be a bit of a gamble. Not too clear on the back crossing- Have you read Carol Deppe's discussion of LBR in her latest book?. |
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Post by verdeperto on Aug 23, 2015 3:53:57 GMT -5
I have a 1 1/2 year old son and he absolutely loves tomatoes, so I want to help him breed his own variety of tomato as he's growing up. The core plan is to start with a four-way cross of very different varieties. Each year from the F2 on, I'll plant some number of plants and let him pick his favorite. Seeds from his favorite will be the F(x+1) generation. That's all pretty simple and should work out just fine. I'll over-plant and cull any weak plants each year and will save backup seeds in the freezer in case of disaster. The interesting bit, and the part of the plan I'd like feedback on, is that I'd like the final tomato to have late blight resistance. My plan for that is to start with a cross between a resistant variety and the selected F2 plant. Each following year, I'll grow out a separate batch of seeds, evaluate for resistance, and make crosses with the plant my son selects. It should be like a normal back-crossing project to introgress disease resistances to a variety, but done at the same time as breeding the variety itself. By doing it this way I can keep the basic project really simple and always keep my son's favorite tomato each year without having to worry about genetic drag from the resistant tomato. Shouldn't take too much extra space since all I care about is getting a tomato or two for seed while evaluating disease resistance. What do you think? That sure left me with a smile on my face. A good warm smile. Made me remember the first time my own own son (who also loves tomatoes) understood they come from plants. I showed him one pointing out the ripe fruit and, for a couple of seconds, you could see his eyes searching the surrounding plants as he comprehended the concepts involved. After those initial seconds, he just wanted all of them. I actually kept seed from the first tomato he picked himself, a Black Krim, and thought of doing something similar to what you propose. Anyway, back to your project. It sounds like your son's choosing criteria might be a set of filters worthy enough on which to base the selection/culling upon. The late blight resistance (as relevant as it is) is something you are looking for... maybe that's daddy's project? Either way, hope you both have a lot of fun doing it. |
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Post by nicollas on Aug 23, 2015 4:22:25 GMT -5
Maybe you could cross some good cultivars with commercial disease resistant lines like Iron lady or Panzer and then select for fruit quality, hoping to keep the disease resistance in (or be sure to keep it but i guess this will be less fun to breed)
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Post by philagardener on Aug 23, 2015 6:39:07 GMT -5
Welcome, andyb ! Fun project that will grow on you! Do you get Late Blight in your garden every year? Otherwise, it is going to be hard to know which plants are carrying resistance alleles. Sounds like a great project in any case! |
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andyb
gardener
Posts: 179
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Post by andyb on Aug 23, 2015 16:53:30 GMT -5
templeton, the back crossing scheme is right out of Carol Deppe's newest book except that, instead of using an established heirloom variety, I'll use the current generation of the variety my son is selecting. The jumping around in the first few generations should add to the fun.
philagardener, I think we get late blight most years when the fall rains start. I'm planning to play around with some resistant varieties in the next couple of years so I guess I'll find out. In any case, if it doesn't hit me one year, I can just replant the next year.
nicollas & verdeperto, Iron Lady is a good candidate for the resistant variety. I could include it from the start, but then I'd have to decide whether to fix the trait and delay another year or two before letting my son start selecting his favorite, or to just take my chances and maybe not get the resistance at all. By doing the back crossing in parallel, it keeps the resistance part of the project from muddying my son's part and increases the chance of getting the resistance in the final variety.
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Post by kazedwards on Aug 26, 2015 10:58:08 GMT -5
What a great project. It sounds like fun and will be great for you and your son.
I am very new to breeding and right now have only gone as far as growing out the any crosses that show up and I like. With that said one of the grow outs I am starting this year is of a tomato called 'Lizzano'. It is a F1 hybrid semi-det. dwarf developed by Pro-Veg Seeds in England. It is said to be the most late blight resistant tomato out there. I have not yet had a problem with late blight so I can't testify to that but I do have F2 seeds from it that I can share if you would like. It is a nice cherry tomato that produce very well and continuously without taking much space. PM me if interested.
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Post by steev on Aug 27, 2015 0:30:39 GMT -5
I must admit that I just think the idea is sweet; best of luck to you and your son.
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andyb
gardener
Posts: 179
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Post by andyb on Aug 28, 2015 1:44:23 GMT -5
Zach, I think I might take you up on your offer of some Lizzano F2 seeds.
I did some googling and couldn't find out which resistance gene(s) it has or whether they are homozygous or heterozygous. Looks like most resistant varieties are heterozygous and F1 hybrids, which makes sense. In any case, if the F1s were heterozygous I could test out my procedure for screening for resistance genes with the F2s. If they were homozygous, compact plants like that might be really convenient in the early years of the project.
Thanks!
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Post by jondear on Aug 28, 2015 23:20:05 GMT -5
It seems there are a lot of fans of Iron Lady on the forum. I guess I should order some from high mowing for next season. This year I made made a cross of Defiant and Big Beef hoping to get a bigger tomato with some disease resistance. Defiant makes decent tomatoes, but they're kind of small for me.
Which brings about a question. Both parents are hybrids will the resulting plant be the same or will there be a lot of variation in them? How many plants should I grow to find some good tomatoes?
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Post by philagardener on Aug 29, 2015 5:31:11 GMT -5
The offspring of two hybrids will vary due to different combinations of genes from the parents (each of whom was diverse).
Think of a bag with lots of different colored marbles and what it takes to draw out a certain set. The more marbles, the more different and complex the sets will be. It's an oversimplification, but there can be a lot of winning combinations. That keeps it interesting!
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Post by nathanp on Aug 29, 2015 22:52:49 GMT -5
If you are looking for homozygous Ph2 and Ph3, here is information I had tracked down in the past.
Homozygous for Ph2 and Ph3
Iron Lady
Lizzano
Skykomish (from Tom Wagner)
Crimson Crush
Heterozygous for Ph2 and Ph3
Mountain Magic
Mountain Merit
Defiant
Jasper (probably has both - not confirmed, unsure if heterozygous or homozygous)
Homozygous for Ph3
Plum Regal
Homozygous for Ph2
Legend (OP)
Possibles/Probables
Matt's Wild Cherry - probably Ph3
JTO-545 - probably Ph2
If you are looking guarantee that both Ph2 and Ph3 are transferred into your F1 (as heterozygous), you need to make sure you are using a homozygous parent.
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andyb
gardener
Posts: 179
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Post by andyb on Aug 30, 2015 1:11:45 GMT -5
Since Defiant is heterozygous for two dominant(ish) late blight resistance genes, on average 1/4 of your cross should be heterozygous for both as well. If you grow 11 plants, this will give you a 95% chance of getting at least one plant with both genes. On average, you're likely to get 2 or 3 plants.
If you save selfed seed from these plants, slightly more than half of the F3 generation should have at least one of both genes. With more selfing and by selecting only the disease resistant ones, the odds get better with each generation.
I don't know how much room you have, but this might be good enough to start with. If you don't like what makes it through the first screening, you can always roll the dice again the next year by planting more F2 seeds.
The main appeal of using Iron Lady or one of the other homozygous varieties is that you get to skip the first step of this process, since all of the children of the first cross will be heterozygous for both genes. As far as disease resistance goes, by the end of next season you should be at the same place if you start over with Iron Lady or if you successfully do the screening with the Defiant cross. I'd say that what you have right now could lead to a fun project.
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Post by jondear on Aug 30, 2015 14:43:06 GMT -5
The sharing of information is what makes this forum such a great place. I am sorely lacking in the technically of it all, but I'm a keen observer in how a plant is performing in my garden. The less than stellar tomatoes will find a home in a canning jar next year and if any really good ones show up, I'll save seed.
I suppose I should grow some of the homogeneous plants as controls if I can acquire seed.
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andyb
gardener
Posts: 179
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Post by andyb on Aug 30, 2015 17:47:01 GMT -5
Agreed on the information-sharing. I've learned a lot while browsing through the archives.
Nathan, your list of resistant varieties is better than I've been able to dig up. Any tips on finding that sort of information?
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