Topic: Blight resistant tomato varieties

[Jayb]

i got some free seeds from t&m  dont know the variety watch this space for cropping and plant health

Great, look forward to your progress. How many are you going to be growing?

[gray1720]

i got some free seeds from t&m  dont know the variety watch this space for cropping and plant health

I have some too, must get them in. As the toms and tatties get blighted most years here, should be a decent test for them!

Adrian

[amphibian]

Crimson Crush does not have f1 in its name but according to the symbol at top right Suttons are claiming it is an F1 in some places.

That's confusing, when I emailed them they wrote back to say they were not an F1 variety.

I think Suttons are being a bit evasive on purpose. It is possible that the variety is an OP but they'd rather create the illusion of an F1 in the hope people don't save seed.

[johhnyco15]

ive put all 5 seeds in and shall plant them along side my fandango to see the difference

[Robert_Brenchley]

They sometimes put 'F1' on an OP variety because some people have got the idea F1's are 'better'.

[Jayb]

i got some free seeds from t&m  dont know the variety watch this space for cropping and plant health

I have some too, must get them in. As the toms and tatties get blighted most years here, should be a decent test for them!

Adrian

Yes normally blight here too, hope they do well for you   
It's encouraging there seems to be several new 'blight resistant' varieties being introduced. Let's hope they are up to the job!

[Jayb]

ive put all 5 seeds in and shall plant them along side my fandango to see the difference

A nice little trial, I wonder if they will let you know the variety later on?

[kGarden]

Crimson Crush does not have f1 in its name but according to the symbol at top right Suttons are claiming it is an F1 in some places.

That's confusing, when I emailed them they wrote back to say they were not an F1 variety.

I can't remember - are Suttons saying that seed will be available next year, but only plants this year?

If no seed promised I wonder if it is only vegetatively reproduced, and thus cannot be crossed (e.g. from F1 parents) reliably and thus will only be grown from "cuttings" (or maybe tissue culture)

I think Suttons should say if it will NOT grow from self-saved seed, otherwise well meaning folk will save seed, grow it next year,a nd lose all their plants to blight :(

[Robert_Brenchley]

Of course it'll grow from self-saved seed. If it's an F1, the result will be variable, but you just pick out the best and save seed from those. It's easy to test for blight resistance; expose them to the disease and see what happens. I'm guessing, but commercial resistance is usually 'vertical resistance' based on a single gene. That makes it easy to select for once you have the gene, but it's probably going to be homozygous - with two copies of the gene - in which case you can't lose it. The weakness is that with vertical resistance the disease is one mutation away from becoming immune to whatever the plant's doing.

[johhnyco15]

I've put all 5 seeds in and shall plant them along side my fandango to see the difference

A nice little trial, I wonder if they will let you know the variety later on?

well i hope so if there any good that is ill still be growing my money maker alicante gardeners delight and 5 other variety's love my toms ill let you know how they all get on

[amphibian]

Of course it'll grow from self-saved seed. If it's an F1, the result will be variable, but you just pick out the best and save seed from those. It's easy to test for blight resistance; expose them to the disease and see what happens. I'm guessing, but commercial resistance is usually 'vertical resistance' based on a single gene. That makes it easy to select for once you have the gene, but it's probably going to be homozygous - with two copies of the gene - in which case you can't lose it. The weakness is that with vertical resistance the disease is one mutation away from becoming immune to whatever the plant's doing.

We're almost certainly dealing with vertical resistance with Ph2 and Ph3 being the deliverer of resistance - these genes are nothing new however and I think Suttons may be making unduly bold claims generally. Unless there is a wild parent providing some horizontal resistance.

There is no reason to assume homozygousity if an F1 because both Ph2 & Ph3 are codominant so if each parent carried just one then the F1 would be dual resistant but heterozygous for both genes. In the F2 only 1:16 plants would be homozygous for dual resistance and 1:16 no resistance with the remaining 14:16 having partial or heterozygous resistance. In any given season it may be very hard to separate the plants with partial from full resistance depending on blight varieties in a given year.

I suspect this is why we have hithertonow seen no dual resistant homozygous varities.

[kGarden]

Of course it'll grow from self-saved seed.

I was meaning "come true". Of course.

[Silverleaf]

There is no reason to assume homozygousity if an F1 because both Ph2 & Ph3 are codominant so if each parent carried just one then the F1 would be dual resistant but heterozygous for both genes. In the F2 only 1:16 plants would be homozygous for dual resistance and 1:16 no resistance with the remaining 14:16 having partial or heterozygous resistance. In any given season it may be very hard to separate the plants with partial from full resistance depending on blight varieties in a given year.

I suspect this is why we have hithertonow seen no dual resistant homozygous varities.

I'm not sure you mean "codominant" here. Codominance (or incomplete dominance) is a relationship between two alleles of the same gene which don't show the typical Mendelian one-or-the-other dominance pattern. The heterozygote shows a different phenotype to the homozygotes, often some kind of intermediate (e.g. a red flower crossed with a white flower showing all pink heterozygous F1s).

Alleles of different genes can't be codominant. Maybe you're thinking of complimentary genes?

I know very little about tomato genes, but it strikes me that it would be relatively easy to get a dual-resistant homozygote from an initial cross of parents with two different resistance genes given enough time and growing enough seeds, simply because tomatoes are self-pollinating.

Homozygotes continue to breed homozygotes, but heterozygotes breed half heterozygotes and half homozygotes. Each generation you'll get fewer and fewer heterozygotes as they segregate. Completely non-resistant plants can be culled. And some of the resistant homozygotes will very likely be double resistant. The only drawback is it takes at least 7 generations to let genetics do all the work for you like this, possibly more. But there's no real work other than the initial cross and growing out plants every year.

[amphibian]

There is no reason to assume homozygousity if an F1 because both Ph2 & Ph3 are codominant so if each parent carried just one then the F1 would be dual resistant but heterozygous for both genes. In the F2 only 1:16 plants would be homozygous for dual resistance and 1:16 no resistance with the remaining 14:16 having partial or heterozygous resistance. In any given season it may be very hard to separate the plants with partial from full resistance depending on blight varieties in a given year.

I suspect this is why we have hithertonow seen no dual resistant homozygous varities.

I'm not sure you mean "codominant" here. Codominance (or incomplete dominance) is a relationship between two alleles of the same gene which don't show the typical Mendelian one-or-the-other dominance pattern. The heterozygote shows a different phenotype to the homozygotes, often some kind of intermediate (e.g. a red flower crossed with a white flower showing all pink heterozygous F1s).

Alleles of different genes can't be codominant. Maybe you're thinking of complimentary genes?

I know very little about tomato genes, but it strikes me that it would be relatively easy to get a dual-resistant homozygote from an initial cross of parents with two different resistance genes given enough time and growing enough seeds, simply because tomatoes are self-pollinating.

Homozygotes continue to breed homozygotes, but heterozygotes breed half heterozygotes and half homozygotes. Each generation you'll get fewer and fewer heterozygotes as they segregate. Completely non-resistant plants can be culled. And some of the resistant homozygotes will very likely be double resistant. The only drawback is it takes at least 7 generations to let genetics do all the work for you like this, possibly more. But there's no real work other than the initial cross and growing out plants every year.

Cornell describe ph2 and ph3 as having incomplete dominance, North Carolina State University used the term codominance and North Californiua used the term 'partially dominant'.

Having read your explanation and various papers on these genes I agree that Codominance is not the correct term. What we are discussing is really incomplete dominance, so I stand corrected I followed the erroneous use of NCSU.

Thinking further though, the incomplete dominance here connotes less resistance within the heterozygous populations - meaning self-selection for the homozygous population should occur easily through repeated selfing in blight active areas/seasons. As the homozygous population are more resistant I suspect that what we may actually have here is the first tomato release of a homozygous cultivar - hence Sutton's fanfare.

[amphibian]

Sorry Silverleaf I've read back through our posts and I think there's been a misunderstanding - Ph2 and Ph3 are separate genes so each could be codominant or partially dominant at their own loci - I was not suggesting they are alleles of the same gene.

[amphibian]

"Thank you for your email.
I am sorry if we have given any conflicting advice.  I can confirm that the Tomato Crimson Crush is definitely an F1 variety"

Suttons reply to me.

However, if the Ph2 and Ph3 are codominant or partially dominant then an F1 that is heterozygous at these loci would not be as resistant as a homozygote. So further breeding should still be bale to produce more resistance.

[Jayb]

How balmy is that! The answer I had was "The Tomato Crimson Crush is not an F1 variety."
Perhaps we should ask Suttons again and make it best out of 3!

[squeezyjohn]

My blight resistant cherry tomatoes "tomatillo de jalapo" bought from real seeds have just come up by self seeding for the fourth year in a row so if you direct sow there will still be time.  In three years not one has shown any blight even when the others have collapsed right next to it ... they eventually die off with the first frosts dropping any remaining fruits and seeding for the next year!

They're definitely a "wild type" tomato which makes thousands of very small cherry/berry tomatoes that are almost all juice and quite sweet when ripe.  The plants don't have much structure - they just sprawl all over the place.  The only down side is they ripen quit unevenly and if you try to pick them by hand they can burst very easily ... I just snip them off with scissors.  A very easy way of adding to the salad bowl.

[Jayb]

I was thinking about growing some tomatillo de jalapo this year but ran out of room and they can be a bit wilful! 

[Jayb]

How balmy is that! The answer I had was "The Tomato Crimson Crush is not an F1 variety."
Perhaps we should ask Suttons again and make it best out of 3!

I emailed Suttons again and asked for clarification, they apologise for the confusion, but Crimson Crush is an F1 variety.
So an F1 they are, by a 2 out of 3 majority!

Seeds will be available this autumn from them.

My little plants don't seem to be growing since I had them, perhaps they are putting out root and the leaves will get going before long.