If you have an F1 tomato with many positive properties but very sensitive to cracking. Is there a real chance to find a selection in F2 that is not or much less sensitive to cracks?
Or is the cracking of tomatoes mainly influenced by recessive genes, so that the chance of a less sensitive F2 selection is minimal?
Neither.
Can u explain?
I’m not sure what the precise answer to your question is.
Since i don’t know how many and what gene’s lead to a sensitivity to cracking.
I think tomato cracking is mostly due to the inside of the fruit swelling/growing faster than the skin. Likely multiple gene’s and environmental conditions are involved. I would not expect a single recessive or dominant gene to influence all factors that can lead to a tomato splitting (or not splitting)
Generally though, F2 plants have large variability and thus are dissimilair from the F1. (F1 hybrid that is)
So you might find a few plants that don’t have the cracking susceptibility. But most likely they will miss some of the other good properties the F1 had.
However, if i try to guess the “goal” of your question. I think you have a F1 hybrid your very happy with, but it splits a lot. Thus you want the positive properties of that F1 without the splitting?
If this is the case, i would first look to culture measures. Splitting usually occurs due to large swings in soil moisture. (rain after dry spel)
Keeping the soil moisture more consistent. (watering during dry period, mulch etc. good soil drainage)
This alone might solve your problem with the F1 plants.
Another option might be grafting them to a more forgiving rootstock (either commercial disease resistant rootstock. Or from a vigorous cultivar or wild tomato)
i have limited experience growing tomato’s, compared to some seasoned gardeners. So take this all with a grain of salt.
I am planning to do some tomato grafting experiments this year. I want to graft some tomato’s to more cold hardy stock. To see if that helps them deal with our climate a little better. (soil temperature takes quite a while to get up to the range tomato’s prefer where we live)
if however you want to recreate the F1 but with improved splitting resistance that would become a lot of work. You would first have to “stabilize” it. (or get the stable parents of the F1 hybrid) and than cross the splitting resistance trait into the parent(s) without affecting to many other traits. I think that would be a hobby project of roughly 6-10+ generations of seeds.
some interesting reading if you want to stabilize an F1 or improve it
basics.
http://kdcomm.net/~tomato/gene/genes.html
what continual self fertilizations does to the genotypes.
http://kdcomm.net/~tomato/gene/genes2.html
how to “stabilize” a hybrid
http://kdcomm.net/~tomato/gene/genes3.html
some things in the explanation are oversimplified. But it gets you there most of the way.
Stabilizing an F1 hybrid
F1 (hybrid)'s are mostly heterozygous. And thus the dominant gene’s tend to give the F1 plant it’s properties.
So you want to have a reasonably large F2 to select your best plant(s) from to self for F3. Each subsequent population can be a little smaller.
The wanted population size will also depend on the amount of traits you want to keep from the F1.
Each time you self-pollinate the tomato you have a 1/4 chance for a homozygous recessive gene (or trait). Likely in the case of the F1 hybrid. This homozygous recessive trait will differ from the F1 (because the F1 traits are mostly dominant) and thus should NOT be used to self and continue to the next generation. Thus you will on average loose 1/4 th of traits from the F1. (lost trait)
Each time you self-pollinate the tomato you have a 2/4th chance for a gene (trait) to stay the same as the F1 has it, heterozygous. (no improvement on that trait)
Each time you self-pollinate the tomato you have a 1/4th chance for a gene (trait) to become homozygous dominant and thus stabilized the trait
these chances are for the average plant. By sowing multiple seeds each generation and picking the plants that most closely resemble the F1. You can loose only a few traits (or none) while **stabilizing more than 1/4th each generation.
There are stil some other effects (like linked gene’s etc) but this will get you mostly there.
I
Thanks for your reaction about the genes. We know how this work and what to do to get a open pollinated variety from F1 to about F7.
We know the cracking and splitting is a combination of many genes and environment. So because its caused by many genes we where thinking its maybe possible to find a F2 that will not crack.
@Fusion_power do u have some experience with this?
What we want is to create a OP variety that we can grow outside in Europe. The commercial F1 that we got have a the desired traits but one very important drawback.
Desired:
Nice color fruit
Very good tasting fruit
Nice shape of fruit
Good production
Earliness is good
A lot of disease resistance
Heterozygous for ph2 and ph3 (very important genes)
Drawback:
Splitting and cracking when there is rain.
Because we want to grow outside and get a lot of rain the splitting is very bad for us. This F1 is cracking much more as other varieties. But these varieties did not have the ph2 and ph3 gene so all get infected with late blight.
So before we start to grow multiple plots with 50 F2 seedlings we want to know if its possible to get a real change to find a less splitting and cracking plant?
If not is maybe better to take a different F1 with ph2 and ph3 genes that have less desired traits but is les sensitive to cracking.
Cracking and splitting take two forms, radial and concentric. Both are related to thickness of skin and how fast the fruit grows. Both are nature and nurture meaning the interaction of genetics with growing conditions. Thicker skin is the boon and bane of crack resistance meaning that it is very effective preventing cracking but customer acceptance goes down fast as the skin gets thicker. If you are just growing seedlings of a commercial hybrid, there is a good chance of finding a stable line that does not crack very often. Unfortunately, most hybrids with packaged disease resistance are from a cross of a highly disease resistant line with a line that has better culinary traits. This means it is a roll of the dice for getting both disease tolerance and crack resistance and other culinary traits by growing out the offspring. You would have to grow about 250 plants per year for a couple of years to find 4 or 5 that are acceptable. You would then have to grow for 7 generations minimum to stabilize the traits. There are a lot of contributing traits such as fruit load. A heavily loaded plant tends not to crack where a lightly loaded plant will split like a limbo line.
If interested in making your own cross: You are in an endemic late blight area. You will have to stay with highly resistant genetics to maintain that tolerance. So this gets down to making a cross where the combination of ph2+ph3+crack tolerance is already present.
You don’t specify any other requirements so I will give you some options to obtain the type tomato you are looking for.
Do due diligence with Mountaineer Delite and I think you will find it could make a very good parent in a cross where good flavor and disease resistance are goals. Amelia has ph2, ph3, F1, F2, and F3. Each of the varieties listed brings a set of very good traits to the breeding plot. Each brings genetic gotchas where traits are either not homozygous or are missing from the variety.
What would I do if I were looking for a commercial tomato to your requirements? I would make a list of each trait that is important and pick parents that have some of those traits.
If I were making a cross and wanted really good flavored disease resistant tomatoes in an indeterminate plant, I would start with Mountaineer Delite and Lynnwood. Cross them and select for disease resistance and good flavored medium size slicers with low cracking.
Here are detailed descriptions of the varieties listed:
Burgess Crackproof - small to medium size, 1.5 to 2 inches diameter, decent flavor but not very sweet. Skin is thick and very resistant to cracking. This tomato is acceptable for canning whole and for sauce.
BBXEPB - A stabilized hybrid of Big Beef X Eva Purple Ball that I selected about 12 years ago. Fruit size is about 2" to 2.5" with relatively thin skin. Production is very high and cracking is very low. This line has the smallest core of any large fruited tomato I grow. Most important, crosses with BBXEPB tend to emphasize production. Flavor is reasonably good. Disease tolerance is very good but does not include ph3. I don’t know if it has ph2, but it grows like it might. It is a compact indeterminate meaning it can be used with Florida Weave type production systems.
Druzba - large round fruit about a pound in size, good flavor, decent crack resistance. Druzba probably does not have ph2/ph3, but it does have decent early blight tolerance and some septoria tolerance. The “round” genes are dominant meaning any crosses will be round in the F1. Core is medium size. Growth habit is indeterminate and tends to be fairly large. Stake culture is difficult because of plant size.
Mountaineer Delite - Combines late blight and septoria tolerance in a large slicing size fruit. It can crack but not usually more than some radial cracking around the stem. The combination of disease tolerance makes this a possible parent for breeding better culinary and production traits.
Mountaineer Pride - Selected for thicker walls, medium size and ability to be shipped along with late blight and septoria tolerance. This is probably your best choice in developing an outstanding flavored disease tolerant non-cracking variety. A cross with Lynnwood or BBXEPB would bring other required traits to the table.
Red Mortgage Lifter - this is a pure play for size. Fruits average large to very large with many up to 2 pounds. It has some fusarium and nematode tolerance but does not have ph2/ph3. If you are looking for huge fruit, consider using RML because it has the size along with a few other useful traits. It is indeterminate and requires very good support meaning either a cage or a fence type trellis.
Amelia - Determinate, ph2/ph3, F1/F2/F3, but no Septoria tolerance in a determinate package. Amelia is a commercial hybrid with relatively bland flavor as compared with Lynnwood. It tends to be very productive. You could grow Amelia and save seed for a few years with very good possibility of stabilizing required traits. Unfortunately, flavor will always be that special commercial bland mix. In a cross with a better flavored parent such as Druzba, ph2/ph3 will segregate in unusual percentages. It will take years of work to find a good flavored late blight tolerant non-cracking line. If you are in it for the long term, start with Amelia and make a few carefully chosen crosses.
Lynnwood - I got this from Chuck Wyatt about 20 years ago and have maintained it since. Flavor is excellent and production ranges from good to very good. It does not have ph2/ph3 but does have early blight tolerance and some tolerance to septoria. Lynnwood is a flavor parent meaning it tends to produce good flavored offspring.
The above are available from Southern Exposure, Sandhill Preservation, Tomato Growers Supply, Harris Seed, and others. Nobody carries all of them, but several places have a few. I don’t think any of them carry BBXEPB, but you can substitute Eva Purple Ball or I might be able to send you a few seed.
The F1 we are talking about is Pruple Zebra and the strange thing is that it have a thick skin.
For the project we already have these lines in F2 and F3:
Galahad, Damsel, Mountain Rouge, Mountain Merrit, Defiant, Cocktail Crush, Crimson Crush, Short Phil, Rubilicious, Abigail, and a few more.
I think Pruple Zebra F1 is the best in flavor but we have to remove the cracking. So u think its possible to find a few plants out of the 250 that have less cracking? That is good news because we can add 250 plants in the project.
Mountaineer Pride (West Virginia 17A) and Mountaineer Delight (WV 17B) I have grown them.
WV 17A resistance is very good here and is homozygous for ph2 and ph3. The growth is weak and the taste is bad.
Still I made a cross WV17 x Sungreen 4029 and these F2 seeds we will add in the project.
WV 17B (Mountaineer Delight) does not have the ph3 gene so it only have ph2 homozygous and the resistance for late blight is to weak. There is a big difference between 17A and 17B.
My goal is to get some different OP varieties that we can grow outside. So how more different F1 plants we use how bigger the chance to get some nice varieties with different traits.
Its also nice to the difference in all the F2 plants from all these different lines.
Ps also Gallahad, Mountain Rouge and Damsel do crack a lot but less as Pruple Zebra F1.
That gives a lot more information to work with. It looks like you are selling in a market or possibly commercially. Do you want a tomato that is visually appealing and also combines the desired traits of late blight resistant as well as crack resistant?
I see you are growing commercial hybrids and attempting to select stable open pollinated lines from their progeny. Are you able to make some crosses of your own?
Are you trying to grow some of the dark flesh tomatoes similar to Carbon, Black From Tula, or Black Krim?
The project is not commercial.
We want OP varieties that can be grown outside without a greenhouse for home grown. Hence taste is important.
Because of rain we need Late blight resistance.
Some F1 varieties give cracked fruit because of rain but if its only a crack its not so bad. But if the fruit cracks and get rotten and its 50% of the fruit its bad.
Yes I also made own crosses and I have black Krim, Cherokee purple and some other high brix Cherry like Lucky Tiger, Sungreen 4029, Opal. But we do not use these for the project.
We are trying to add Medusa F1 in the project because its heterozygous for ph2 and ph3 and have good taste. But that is for 2024.
At this moment we use commercial Hybrids with late blight resistance. Maybe over a few years when we can get homozygous plants for ph2 and ph3 we can make own crosses and ad new better tasting varieties. But is seems in the USA we will get a lot of commercial hybrids with ph3 genes and better taste like Purple Zebra F1 and Hot Streak F1.
So do u think we can ad Purple Zebra F1?
These i gow in a greenshouse to prevent late blight infection.
This is a bit of an unusual recommendation, but Doug Heath developed a tomato for Burpee that they sell as Tye-Dye hybrid. The article I read about it says he included ph2 and ph3. I don’t have a link to the original article. Burpee.com lists it. Be careful as there are other tomatoes that have similar names. I’m fairly certain Burpee picked it up as an exclusive.
The other tomatoes I think you could grow are still tied up in proprietary breeding programs. I’ll ask around to see if you could get some seed. Sometimes they will be released after several years of breeding use.
I would really appreciate that
Hi lovely people,
thanks so much for your important work and for all the valuable information you´re sharing!
We´re also working on new open pollinated varieties with high late blight resistance. We´re located around Graz/Austria. We´re currently also focusing on the ph-2 and ph-3 combo, but we´ll also trial as many lycopersicum varieties with (potential) alternative resistance as we can. we´ll pyramide (combine them all) and see to which level of resistance we´ll get that way. third approach (and absolutely neccessary, because at some point in the future ph-2 and ph-3 will be overcome by the pathogen): obtaining new resistance genetics from solanum habrochaites and solanum pimpinellifolium accessions and getting them into bigger fruited lycopersicum.
btw i just discovered that lee of j&l gardens in new mexico offers a probably stable new variety resulting from a cross of a lycopersicum parent with solanum habrochaites accession LA1777. that´s great news! LA1777 is one of the most promising habro accessions i came accross several times when i checked out various studies.
Wild Child
Lee of J&L: “This is a dwarf version of a cross I originally made to LA1777, a wild tomato species. It bears loads of pinkish orange cherries on a mounded plant about 1 foot tall. By midseason, it looks like there are more tomatoes than leaves. The flavor is fresh and crisp without the musky aroma of the wild parent. Wild Child inherits resistance to blight and cold tolerance from LA1777. The particulars of the genetics would indicate it is stable, but these lines have tricked me before.”
we should definitely try to get seeds of wild child over to europe. and maybe lee even has bigger fruited lines resulting from crosses with LA1777.
…i´ll share more about what we do and plan to do sometime later, when i find the time…
i had to join the board, because i might be able to help out with some infos as well:
Vivagrande (red beefsteak)
Rondobella (red saladette)
Resibella (red cocktail)
Primabella (red cherry)
from bernd horneburg / the organic outdoor tomato project in germany (and available via culinaris seeds) all contain ph-2 and ph-3 homozygous according to a trustworthy source. so they should all be good parents. i might be able to share seeds. i might also have a significantly bigger (slightly plum shaped) version of primabella that might be especially valueable. found it last year and will check if it´s stable this season. primabella contains some alternative resistance in addition to ph-2 and ph-3. so it´s probably the variety with the highest overall late blight resistance available today.
@Roland maybe Vivagrande and/or Rondobella might be good parents for you? I´m sure you already trialed them, right? How did you like them? Did they crack? They didn´t crack at my place in 2022.
btw would you be willing to share some f2 seeds of purple zebra with me? that´d be appreciated a lot! i heard that it is somewhat late ripening. was it mid-season for you?
Again, thanks so much, @Fusion_power, @Roland, ea!
LA1777 has been a hobby horse for several breeders. IMO, LA2175 has more potential.
thx for the info,@Fusion_power! have you been working with habrochaites when it comes to breeding? btw do you know from whom we might be able to get ph-5.1 and ph-5.2 material?
The tomato breeder at NCSU may be using some PH-5x material. Florida has some literature showing it on chromosome 1 and attempting to map it in fine detail. I don’t know anyone who has seed currently.
Yes is have grown:
Primabella
Rondobella
Resibella
Vivagrande
Form me the fruit of Galahad F1 and F2 is much better tasting and also production of Galahad is much better as Vivangrande.
For example Galahad F1 have a brix of 5. Galahad F2 have a brix of 4,5 to 6,0 and Vivagrande have a Brix of 3,5.
In the F3 I found a Galahad that have some fruit with Brix 8,0 beef size.
From DNA test we found that Vivagrande is homozygous Ph-3, the others are homozygous Ph-2 and Ph-3.
The resistance is very good in Netherlands. But the fruit quality can be much better. So we hope to breed better resistant varieties.
In 2023 we will test 5000 plants and about 10% is F2 Purple Zebra.
We mainly focus on dehybridising hybrids that possess Ph-2 and at least Ph-3. Only Ph-2 appears to be insufficiently effective in Northern Europe.
What is your source that Vivagrande is also homozygous for Ph-2?
To provide an update on the project and Purple Zebra F2.
We found a lot of variation in the F2 from small fruits, round fruits and even beef size.
And there are some very tasty fruits with a brix of 7, they have a very sweet aftertaste while other tomatoes lose the aftertaste.
And as you can see in the picture, most of them are not sensitive to cracking. These do have a somewhat thick skin.
Fruit on the top row, 4th and 5th from the left have some potential. You are getting some effects from the “sun” gene which elongates fruit. How do they taste?
