Off-types so far (2010)

[Tania]

Another offtype added to the list - Gerig. I got RL seedling instead of PL.

This brings it to:
24% of new to me PL varieties grown this year show some degree of crossing.

I am still waiting for the last LP to get the true leaves to get the final %-ages.


In a meantime, I am also checking my own PL seeds for purity - 2 batches of KBX, Brandywine Sudduth's, Orlov Yellow, and Aunt Gertie's Gold. 20-25 seeds planted in each batch, 100% seedlings are PLs. Still waiting for Gary'O Sena seeds to emerge...

Tania

[mensplace]

Tatiana
Thanks for the sanity check! Noticed yesterday in my potting from seedlings of Jeff Davis that although I was very careful in organizing my seed rows with 1/2 inch between seeds in rows and an inch between the rows, there was a mix of those with RL and PL. In fact, as you noted, also saw this among other PL varieties. Does this mean that the actual fruits will not be, for instance, Jeff Davis, or simly that the plant with the RL simply carries a gene for a different leaf type? I saw this in so many PL varieties that I was seriously wondering how in the world I could have made such a mistake in seeding and was considering assigning the RL's to my UK (unknown) collection as they bore different leaves than what I knew they were "supposed" to be.

Next year I will be spacing my rows and individual seeds in the rows a bit further apart. I used the ESPOMA with organics and micro-organisms and the root systems are prodigious and I hate having to so damage the root mass by such close planting that I lose a considerable percentage of the roots when using and fork an some pulling apart to separate the individual plants.

[carolyn137]

Does this mean that the actual fruits will not be, for instance, Jeff Davis, or simly that the plant with the RL simply carries a gene for a different leaf type? I saw this in so many PL varieties that I was seriously

*****

I wish I could remember where I just did a long post about this here, but I can't remember, so....

I'm not going to go into the genetics of the leaf genes but will just make a few summary comments.

There are two genes that determine leaf shape.

Let C =RL, let its allele c = PL and C is dominant to c

CC is homozygous dominant and RL is the leaf from

Cc is heterozygous and the leaf form is RL b'c C is dominant to c

cc is homozygous recessive and the leaf form is PL.



If a variety is RL and then you see some PL's popping up in the same seed batch what can you conclude.

It has to do with the way in which an RL can go to PL. If it's a single spontaneous mutation, and those are permanent, genetically stable and thus heritable, then the only difference between an original RL and it's PL is a change in the leaf form and all else will be the same. And that would be Cc going to cc.

But there's more than one way that can take an RL to a PL, different molecular ways such as looping out of the DNA, inversions, repeats, etc., and in that case more than one gene, such as the leaf gene, can be involved and thus a PL variant of an original RL will not be the same in all ways as the original RL. That could be CC going to cc or Cc going to cc.

If I'm sowing seed for AGG, for instance, which is PL, and all are PL from self pollenization that's fine.

If I get RL plants from AGG then I know that some x pollination has occurred and I discard such RL's. True back mutations from cc to Cc seldom if ever occur.

If I grow Jeff Davis which is PL, which I have, and I get RL plants I discard them b'c it means that x pollination has occurred.

RL is dominant to PL and that's how you know that if a known PL has RL seedlings that X pollination has occurred.

There's Spudakee, a PL Cherokee Purple, as well as the variety Cherokee Purple Potato Leaf and the question is whether Spudakee and Cherokee Purple Potato Leaf are identical to each other and how each of them relate to the original CP. Some who have done comparisons say that they are the same, some don't. You have to grow the original RL and any PL variants in the same season before you can make any con clusions.

So, I do not assume that a PL variant of an RL is the same in all ways except leaf form b/c of different genetic mechanisms that can allow for an RL to become PL.

If a PL variety shows some RL's it's a safe bet that it's the result of X pollination b'c the gene for RL is dominant to PL. Also, going from a PL back to an RL is called a back mutation and is very very rare indeed.

Of course X pollinations can and have led to some new varieties, it's one of the major ways in which new varieties appear, if one has the sapce and time to make selections from that initial hybrid that appeared b'c of X pollination.

But in general I discard all seedlings that are not the right leaf form from the get go, b'c I have no way of knowing if the leaf form change is the only genetic difference from the original.

And I'll end by saying that PL's can cross pollinate with PL's giving you a PL hybrid that has fruits that are not right, but the leaf form is and RL's can cross pollinate with RL's giving you RL plants that are hybrids as well where the leaf form is correct but the fruits are not correct.

Final summary: I would not assume that an RL variant of a PL is identical in all ways to the RL original except for leaf form for two reasons, first b'c back mutations are extremely rare and second, the most common occurence for that to happen is that the RL variant is the result of X pollination of the original PL with an RL b'c RL is genetically dominant to PL.

[Tania]

another off-type to add to the list today: Black Elephant.
All my seedlings are RL, but this variety should be PL.

This brings it up to 28% off-types.
Sigh.

Tania

[Tania]

mensplace, if you are observing PLs instead of RLs, I'd suspect seed mixup - it is much more likely than a Rl->PL mutation.

[Tania]

Carolyn,

thank you so much for such a wonderful introduction into the tomato genetics!

Tania

[carolyn137]

Originally Posted by Tania

Carolyn,

thank you so much for such a wonderful introduction into the tomato genetics!

Tania

Tania, it seems to me that you're seeing a fairly high rate of wrong leaf varieties this season.

Do you acquire most of your new ones by buying commercially from some place or by trading or via SSE requests or a combination of those sources and can you make any conclusions as to which sources for you have been the worst in terms of problems?

I'm just curious, and by the way, you know I'm not a strong advocate of trading seeds in general, not only b'c my past experiences showed that many I received were cross pollinated, but also b'c I feel very strongly about folks buying their heirloom tomato seed from places such as yours and other small family run businesses.

it's you folks who do the most to help with seed preservation as I see it, along with those who offer and reoffer their listings in the SSE YEarbooks as you and quite a few others also do.

[mtbigfish]

Originally Posted by carolyn137

Tania, it seems to me that you're seeing a fairly high rate of wrong leaf varieties this season.

Do you acquire most of your new ones by buying commercially from some place or by trading or via SSE requests or a combination of those sources and can you make any conclusions as to which sources for you have been the worst in terms of problems?

I'm just curious, and by the way, you know I'm not a strong advocate of trading seeds in general, not only b'c my past experiences showed that many I received were cross pollinated, but also b'c I feel very strongly about folks buying their heirloom tomato seed from places such as yours and other small family run businesses.

it's you folks who do the most to help with seed preservation as I see it, along with those who offer and reoffer their listings in the SSE YEarbooks as you and quite a few others also do.

Carolyn
I am really glad you wrote that because for me it has been difficult because of separation issues and to take the time to bag, save and ferment seed etc.
Since this is the first time I have ever traded or received seeds privately over the internet in trade I have been a bit anxious to see if the seeds grow true.

When I no longer received family saved seed from relatives in Missouri, Kentucky, Pa, Iowa, Chili and other So American countries and Ohio(all have passed on) I started buying seed from commercial or small private businesses. Never a Burbpee or big company though this year I got curious over someones post on $.20 seeds from Wally mart.(got some beens, herbs and peppers)
I do not mind growing extra plants to give away to neighbors etc schools etc or trading with a friend who bought commercially however he is no longer around so tried the trade scene this year.

Thanks
Dennis

[Tania]

Originally Posted by carolyn137

Tania, it seems to me that you're seeing a fairly high rate of wrong leaf varieties this season.

Do you acquire most of your new ones by buying commercially from some place or by trading or via SSE requests or a combination of those sources and can you make any conclusions as to which sources for you have been the worst in terms of problems?

I'm just curious, and by the way, you know I'm not a strong advocate of trading seeds in general, not only b'c my past experiences showed that many I received were cross pollinated, but also b'c I feel very strongly about folks buying their heirloom tomato seed from places such as yours and other small family run businesses.

it's you folks who do the most to help with seed preservation as I see it, along with those who offer and reoffer their listings in the SSE YEarbooks as you and quite a few others also do.

Carolyn,

Out of the 7 PL varieties that showed incorrect RL seedlings, 4 are commercial seeds, 2 from SSE members, and 1 from a trade.

The remaining 3 RL that showed incorrect PL leaf: 1 from commercial, 1 from SSE member, and 1 from a trade.

So the majority of the incorrect seeds are from commercial sources and SSE members.

Tania

[Tania]

I should also comment on the ones that did grow true (PLs that is):

6 - from SSE members
9 - from trades with non-SSE members
4 - from commercial sources

This shows that my own very limited experience with seed trading is actually quite positive wrt the seed purity - but I only traded with very few folks that I know well (not sure it this qualifies for a 'trade' ).

Tania

[dice]

mensplace:

If you are getting PLs from what were supposed to be
RL seeds, those go straight to "unknown" (if you do not
just pull them and toss them). They are stray seeds with
a minimal chance that they were produced by mutation,
as Carolyn explained above. If you are getting RLs from
PL seeds, those can be stray seeds ("unknown") or
chance crosses of an RL plant with the PL plant that the
seeds were saved from ("PL variety x unknown").

In the second case, you do not know which it was until
you save seeds from the RLs and grow several of them
out the following year. If the plants from the seeds saved
from those RLs are a little different from each other
(or very different from each other in some cases) and
different from the original RL plant that you saved seeds
from, then the RL was a cross, probably with the PL that
you were supposed to get, and there should be some PL
plants in that following year's seedlings from that line.
If those next year's plants are exactly alike and the same
as the RL plant that you saved seeds from, then that
"RL from seeds that were supposed to produce PL plants"
was a stray seed of an unknown, genetically stable,
open-pollinated cultivar.

[Tania]

Originally Posted by carolyn137

There are two genes that determine leaf shape.

Let C =RL, let its allele c = PL and C is dominant to c

CC is homozygous dominant and RL is the leaf from

Cc is heterozygous and the leaf form is RL b'c C is dominant to c

cc is homozygous recessive and the leaf form is PL.

Carolyn,

So what happens when a 'Cc' tomato crosses with a 'cc' tomato?

Tania

[stormymater]

50% Cc & 50%cc from Cc x cc

Interestingly isn't the PL in the RL how KBX came into being?
I surely love my KBX!

[carolyn137]

Originally Posted by stormymater

50% Cc & 50%cc from Cc x cc

Interestingly isn't the PL in the RL how KBX came into being?
I surely love my KBX!

I just did a huge long post going thru some genetics and when I went to post it it said server error, so this is just test and if it posts I'll just have to come back later and try to remember all that I wrote in that post.

[carolyn137]

Originally Posted by carolyn137

I just did a huge long post going thru some genetics and when I went to post it it said server error, so this is just test and if it posts I'll just have to come back later and try to remember all that I wrote in that post.

OK, I'll try again but I know I can't remember all that I posted and this time I'll cut and paste what I write before hitting the button.

Tania, Stormy is correct that Cc X cc will be half RL and half PL. Here's how it goes:
c c
C Cc Cc

c cc cc

But we don't know the genotype ( actual genes) as opposed to the phenotype ( what it looks like), for any of the varieties that most of us grow.

I used to think that a PL variant of an RL came about from a single spontaneous mutation of Cc that led to cc. Such spontaneous mutations involve only one base pair in the DNA and are permanent and heritable. But after some discussions with Keith Mueller I decided that I was ignoring other possibilities.

First, to go from CC to Cc to cc is not probable b'c it requires two sequential mutations which is possible but not probable and could be spaced out, time-wise, in years.

But other molecular mechanisms such as looping out, inversions, repeats, deletions, can also occur in which case more than one gene, the leaf form gene, can be affected, such as taste, yield, etc.

Take as one example the variety Spudakee ( a PL Cherokee purple named by Bill Malin) compared with Cherokee Purple Potato leaf as found and named by Jere Gettle in his growouts.

SOme folks have done direct comparisons with one or both of the above with CP (RL) in the same season and some have said they see no difference and others have said they do experience differences.

i then had discussed the one variety I had, Polish C that went from PL to RL, but I'll leave that one out this time.

So I no longer assume that a PL variant is the same as the original RL.

I grew KBX maybe the second year after Martha ( gardenmama) found it b'c we were both posting in the AOL tomato forum at the time so that would have been prior to maybe 2000, and I found that KBX gave a better plant, the taste was the same and yield was higher, and quite a few folks have said the same, so it would appear that more than the leaf gene was affected.

I don't knowingly distribute seeds for varieties that have a leaf form different from the original, nor do I do same for varieties that have had an epidermis mutation that allows for a red to go to pink ( yellow epidermis to Clear), or the reverse. And in the past I've mainteined several varieties in both their red and pink forms.

Cherokee Chocolate, for instance, is the result of the normal clear epidermis on CP going to yellow thus resulting in a mahogany color.

And then I discussed the renaming of known varieties and mentioned Roger's Best Black and Dot's Delight as examples, but won't go through that either.

I feel strongly that seeds that conform to the original description of a variety should be the ones to be distributed, and yes, I recognize that some variants might be better for some folks who might have detected differences, but well, it's just the way I feel.

Hope that helps.