Purple Haze

[dice]

Travis is right, Purple Haze was an F4 x Black Cherry cross
(history is here:
http://t-garden.homeip.net/mwiki/index.php/Purple_Haze
).

My point still stands, though, in that the F4 parent was
a unique combination of genes as far as we are concerned
and not reproducible. Even if someone tried, how would they
get the right F2, F3, and F4? Ask Keith to taste a few thousand
of them and see if one of them is it? Face it, anyone who tries
is only ever going to get close at best, even the original breeder.

The suggested crosses and possible backcrosses above are
ways to cross Black Cherry with sets of genes that are at least
in the neighborhood of the original F4 parent of Purple Haze
(and are stable OPs as well, which leads to reproducible
results).

BC x Spudakee and BC x Vorlon would probably eliminate
the Brandywine lineage, but the F1s might still compete with
Purple Haze as a desireable, quality tomato. (Vorlon
is a stabilized Cherokee Purple x Pruden's Purple. Spudakee
is Cherokee Purple x unknown PL, as far as I know. So some
subset of the Cherokee Purple genes and all of the Black Cherry
genes would still be there.)

[dice]

A little background for anyone confused by this discussion:

The web site at the link below explains in simple terms Tomato
Genetics and what happens with the various F? generations
after a cross:

http://kdcomm.net/~tomato/gene/genes.html

(The above explanation pretty much applies to all plants
that self-pollinate, by the way.)

The thing to remember is, if you have, say, an F2, second
generation of self-pollinated offspring after a cross, and it
has 50% matching gene pairs and 50% not matching gene
pairs, which out of its hundreds of genes are the non-matching
pairs? The answer is likely to be different for every F2 seed
saved from a particular F1 plant, up to some huge number of
seeds beyond all of the possible combinations.

Say a tomato plant had 100 gene pairs (I don't know the exact
number that they actually have). The first F2 seed might have
matching gene pairs in positions 1-50, and not matching gene
pairs in positions 51-100. A second F2 seed might have
matching gene pairs in positions 1-12, 14-18, and 59-92, and
non-matching pairs in the other positions.

And that same randomness is apparent in several succeeding
generations of self-pollinated offspring. Even at F4, with only
on average 12.5% non-matching pairs, that 12.5% will be
scattered randomly across all of the possible gene pairs in the
plant's DNA for any given F4 plant.

This makes it difficult to reproduce a new F1 (like Purple Haze)
once the original F4 parent plant with its random set of
non-matching gene pairs is no longer growing. That F4 parent
was likely the only plant in existence that had its exact set of
matching and non-matching gene pairs.

This problem mostly goes away when both parents are stable,
open-pollinated plants with virtually all matching gene pairs.
You can always grow another parent plant from a different seed
and get the same set of genes to produce F1 seeds with.

Unfortunately that was not the case with Purple Haze.
Recreating the gene set of that particular F4 parent plant
that Keith used as a parent of Purple Haze is not practical.
So the alternative is to look for something close enough to
that F4 to produce a slightly different F1 (or even an OP if
going forward with Purple Haze growouts) that is just as tasty
and productive as Purple Haze.

[travis]

Originally Posted by dice

Recreating the gene set of that particular F4 parent plant that Keith used as a parent of Purple Haze is not practical.

So the alternative is to look for something close enough to
that F4 to produce a slightly different F1 ...

Yes, impractical to the nth degree as you pointed out.

Therefore, the alternative to use something close enough to the F4 parent is the more practical approach, and one that should result in a close approximation.

[rnewste]

OK, Thanks for all the information dice and travis. I think I now understand about 7% of how all this gene stuff works.


So I guess that if I want the "real deal" Purple Haze F1 tomatoes, my only option is to over-winter suckers every year from the original plant. I have 3 of them going at the moment and I just need to keep them from turning into stick figures. Any suggestions on how to build up the stem vigor in a window-box setting like this?



Ray

[Gobig_or_Gohome_toms]

I am by far no expert on this subject but depending on the time left to transplant would it be possible to root another sucker and time it so it does not get to leggy prior to being put in the tainers?

[rnewste]

Go Big,

I was just looking at the plants 10 minutes ago - - thinking the same thing!!

There are 3 suckers that are currently about 4 inches long that are candidates to be snipped to keep the "cycle" going.

I am going to try some small tomato cages in the meantime to try to keep the fragile main stems from breaking.

Since tomato plants are supposed to be Perennial, I wonder how many years I could keep this F1 lineage going???

Ray

[kevokie]

Originally Posted by rnewste

Since tomato plants are supposed to be Perennial, I wonder how many years I could keep this F1 lineage going???

Ray

To infinity and beyond!

[Raymondo]

That's what I did with an F2 I grew last season Ray. Kept it going over winter from cuttings, then in early spring took cuttings from the overwintered plant and got them going. Treated them like my normal transplants after that. In the garden this season they grew exactly as they had the season before, producing the same delicious fruit. I intend doing it again this year!

[dice]

There is one other complication in the genetics of
segregation that I described above, and that is
dominant versus recessive matching pairs. If a
non-matching pair of genes is a dominant-recessive
pair, then when it eventually becomes a matching pair
of genes in some subsequent F? generation, that
matching pair could be dominant-dominant or
recessive-recessive, and which it is will produce
different characteristics in the plant grown from
that seed.

So not only are the positions of the matching pairs and
non-matching pairs (among all of those available in the
plant's DNA) random in pre-stable generations after a cross
(like F4s), but whether the matching pairs are two dominant
genes or two recessive genes is also random at gene positions
where the original non-matching pair in the F1 was
dominant-recessive.

(If both parents had dominant genes at that gene position
or both had recessive genes at that gene position, then there
was never a non-matching pair there, even in the F1.)

[travis]

And if as you seem to contend, the F4 parent wasn't stable, even the F1 sibling could express some variations. And I agree there is a 12.5% likelihood there. But none of this is really all that important.

[dice]

And if as you seem to contend, the F4 parent wasn't stable, even the F1 sibling could express some variations. And I agree there is a 12.5% likelihood there.

One would expect so. With non-matching gene pairs, the
F4 parent could contribute either gene to any given seed
from the cross with Black Cherry.

It could have been a lucky accident that the variability
produced by the non-matching pairs in the F4 parent
seemed to have neglible effect on fruit set, flavor, etc
when crossed with Black Cherry.

But none of this is really all that important.

Ray was wondering why the original breeder does not just
produce more Purple Haze F1 seeds. The answer is that
if he has not cloned the original F4 parent of Purple Haze,
that one exact plant itself, there is no practical way to
recreate its unique genetic makeup.

That was the fact that I was hoping to communicate
in discussing the parentage of Purple Haze and the basics
of tomato genetic stabilization, that the lack of supply of
more seeds of the original F1 is not simply the result
of some breeder's arbitrary refusal to produce more of them.

It's like trying to re-breed Seabiscuit.

[travis]

No one has confirmed that the entire batch of original PH F1 seeds came from just one F4 seed mother.

And no one has confirmed yet whether the breeder has or hasn't got additional F4 parent line seeds remaining.

But it has been an interesting discussion. Thanks.

[rnewste]

dice,

Thanks. While I didn't comprehend 93% of the discussion, now I can understand why Keith M. may have run out of a stable and continuous supply of seeds for the same Purple Haze as the original F1.

I don't mind over-wintering suckers at all to keep the "circle of life" perpetuating, I just hope the plants don't come down with a fatal disease in the future, as I would miss the unique taste of the "real deal".

(I'm just glad I muck around in 65 nanometer Semiconductor technology as it is far less complicated than all this gene-pairs stuff).

Ray

[dice]

(I'm just glad I muck around in 65 nanometer Semiconductor technology as it is far less complicated than all this gene-pairs stuff.)

Using the gene mix in plants of pre-stable generations as a parent
of an F1 is like sampling the background hum of the universe (radio
static, et al) to seed a random number generator. It may work great,
but the process that led to the generation of a particular output
number is not reproducible unless you keep a copy of the sample
that you collected. (When can we expect that in actual hardware,
by the way? All of these other ways of collecting entropy seem
like such a high-overhead kludge in comparison.)

Edit:

For the technology layman, "entropy" here means "unpredictable
sequences of 1s and 0s".

[rnewste]

Carl Sagan, where are you when we need you??

Ray