I pricked out 60 seedlings of Amsonia hubrichtii yesterday (seeds from
my own plant), sown in spring. I was most surprised to see that there
was a marked variation in stem colour; five in six were deep pink, the
rest were a pale green. There was no difference in size.

I have never seen this sort of variation in colour before. I assume that
A. hubrichtii is self-fertile - it's not exactly a common perennial,
although I have seen it for sale at the odd garden centre. I haven't
seen any other Amsonia plants around, even tabernaemontana, which is a
lot more common and might cross-pollinate hubrichtii.

Any explanations for the variation in colour, and the 5:1 ratio?

--

Jeff

In article ,
Jeff Layman wrote:

Any explanations for the variation in colour, and the 5:1 ratio?

Some plants do that, but I don't know why. In others, it can be an
indication of flower colour or some other interesting property.
However, 5:1 is as likely as any other ratio, because the optimal
level of a gene in a population can be almost anything. Also, in
60 plants, 5:1 is not significantly different from 4:1, which is
the proportion that an equiprobable recessive gene exposes itself.


Regards,
Nick Maclaren.

On 26/09/2016 13:27, Jeff Layman wrote:
I pricked out 60 seedlings of Amsonia hubrichtii yesterday (seeds from
my own plant), sown in spring. I was most surprised to see that there
was a marked variation in stem colour; five in six were deep pink, the
rest were a pale green. There was no difference in size.

I have never seen this sort of variation in colour before. I assume that
A. hubrichtii is self-fertile - it's not exactly a common perennial,
although I have seen it for sale at the odd garden centre. I haven't
seen any other Amsonia plants around, even tabernaemontana, which is a
lot more common and might cross-pollinate hubrichtii.

Any explanations for the variation in colour, and the 5:1 ratio?


The obvious explanation is that the parent plant is heterozyous for stem
anthocyanin (or other pigment, but google provides a citation for the
presence of anthocyanins in Amsonia) production, and a proportion of the
seedlings are homozygotes for the recessive allele. Perhaps you'll later
find a pleiotropic effect on flower colour.

The expected mean ratio of offspring from a self-pollinated diploid
dominant/recessive heterozygote is 3:1. 50:10 isn't that far off 45:15 -
you'd need someone with more current statistical expertise to say
whether the difference is statistically significant for a sample of that
size.

--
SRH

On 26/09/16 13:56, Chris Hogg wrote:
On Mon, 26 Sep 2016 13:27:18 +0100, Jeff Layman
wrote:

I pricked out 60 seedlings of Amsonia hubrichtii yesterday (seeds from
my own plant), sown in spring. I was most surprised to see that there
was a marked variation in stem colour; five in six were deep pink, the
rest were a pale green. There was no difference in size.

I have never seen this sort of variation in colour before. I assume that
A. hubrichtii is self-fertile - it's not exactly a common perennial,
although I have seen it for sale at the odd garden centre. I haven't
seen any other Amsonia plants around, even tabernaemontana, which is a
lot more common and might cross-pollinate hubrichtii.

Any explanations for the variation in colour, and the 5:1 ratio?

Not really answering your query, but as I've never heard of it I
Googled for images. http://tinyurl.com/ze5nmst I'm puzzled, as two
foliage colours seem to be available: golden yellow and bluish green.
Is the golden yellow it's autumn colour before it dies back, or are
there different cultivars? If the latter, might this account for the
different stem colours in your seedlings?

I've never seen foliage colour other than green, except in the autumn.
Some of my seedlings are changing foliage colour, but it isn't just the
green or pink stemmed ones - it seems pretty equally divided.

--

Jeff

In article ,
Stewart Robert Hinsley wrote:

The obvious explanation is that the parent plant is heterozyous for stem
anthocyanin (or other pigment, but google provides a citation for the
presence of anthocyanins in Amsonia) production, and a proportion of the
seedlings are homozygotes for the recessive allele. Perhaps you'll later
find a pleiotropic effect on flower colour.

For every complex problem there is an answer that is clear, simple, and
wrong :-) That may be the explanation, but it may well be mistaken.
If the flower colours are different according to the stem colour,
I agree that would make this fairly certain.

The expected mean ratio of offspring from a self-pollinated diploid
dominant/recessive heterozygote is 3:1. 50:10 isn't that far off 45:15 -
you'd need someone with more current statistical expertise to say
whether the difference is statistically significant for a sample of that
size.

Current, I can't do, but I don't need it. That is the mean ratio
ONLY if it is a single, Mendelian gene AND the parent reproduces
purely by haploid/diploid self-pollination. In my previous post,
I missed that it was a single parent, so said something irrelevant.
I agree that is the simplest plausible explanation. Anyway, as I
said, 50:10 isn't significantly different from 45:15.


Regards,
Nick Maclaren.

On 26/09/16 18:59, Nick Maclaren wrote:
In article ,
Stewart Robert Hinsley wrote:

The obvious explanation is that the parent plant is heterozyous for stem
anthocyanin (or other pigment, but google provides a citation for the
presence of anthocyanins in Amsonia) production, and a proportion of the
seedlings are homozygotes for the recessive allele. Perhaps you'll later
find a pleiotropic effect on flower colour.

For every complex problem there is an answer that is clear, simple, and
wrong :-) That may be the explanation, but it may well be mistaken.
If the flower colours are different according to the stem colour,
I agree that would make this fairly certain.

The expected mean ratio of offspring from a self-pollinated diploid
dominant/recessive heterozygote is 3:1. 50:10 isn't that far off 45:15 -
you'd need someone with more current statistical expertise to say
whether the difference is statistically significant for a sample of that
size.

Current, I can't do, but I don't need it. That is the mean ratio
ONLY if it is a single, Mendelian gene AND the parent reproduces
purely by haploid/diploid self-pollination. In my previous post,
I missed that it was a single parent, so said something irrelevant.
I agree that is the simplest plausible explanation. Anyway, as I
said, 50:10 isn't significantly different from 45:15.

I'm sorry to say I have been wasting your time. The plant I have is
*not* Amsonia hubrichtii (although that's what it said on the seed
packet). It has a number of almost ripe seeds heads and I thought I'd
have a look at them today. It was then that I examined the leaves - they
are lanceolate, glabrous under a x10 lens, and around 16 cm long and 5
wide. The stems are over a metre long. That probably makes it A.
tabernaemontana, a cultivar of it, or possibly a hybrid.

It will be interesting to see if the flowers vary between the green and
pink-stemmed plants.

--

Jeff

In article ,
Jeff Layman wrote:

I'm sorry to say I have been wasting your time. The plant I have is
*not* Amsonia hubrichtii (although that's what it said on the seed
packet). It has a number of almost ripe seeds heads and I thought I'd
have a look at them today. It was then that I examined the leaves - they
are lanceolate, glabrous under a x10 lens, and around 16 cm long and 5
wide. The stems are over a metre long. That probably makes it A.
tabernaemontana, a cultivar of it, or possibly a hybrid.

It will be interesting to see if the flowers vary between the green and
pink-stemmed plants.

You haven't :-) It's not a plant I know, and both Stewart's and my
points apply generically, so are equally relevant. Yes, I agree
that it will be interesting. I have seen other plants with varying
seedling stem colour, that disappeared without other visible effect
once they developed a proper stem - and, as Stewart says, there are
plants where it indicates the presence or absence of a pigment.


Regards,
Nick Maclaren.

On 27/09/2016 16:59, Jeff Layman wrote:
On 26/09/16 18:59, Nick Maclaren wrote:
In article ,
Stewart Robert Hinsley wrote:

The obvious explanation is that the parent plant is heterozyous for stem
anthocyanin (or other pigment, but google provides a citation for the
presence of anthocyanins in Amsonia) production, and a proportion of the
seedlings are homozygotes for the recessive allele. Perhaps you'll later
find a pleiotropic effect on flower colour.

For every complex problem there is an answer that is clear, simple, and
wrong :-) That may be the explanation, but it may well be mistaken.
If the flower colours are different according to the stem colour,
I agree that would make this fairly certain.

The expected mean ratio of offspring from a self-pollinated diploid
dominant/recessive heterozygote is 3:1. 50:10 isn't that far off 45:15 -
you'd need someone with more current statistical expertise to say
whether the difference is statistically significant for a sample of that
size.

Current, I can't do, but I don't need it. That is the mean ratio
ONLY if it is a single, Mendelian gene AND the parent reproduces
purely by haploid/diploid self-pollination. In my previous post,
I missed that it was a single parent, so said something irrelevant.
I agree that is the simplest plausible explanation. Anyway, as I
said, 50:10 isn't significantly different from 45:15.

I'm sorry to say I have been wasting your time. The plant I have is
*not* Amsonia hubrichtii (although that's what it said on the seed
packet). It has a number of almost ripe seeds heads and I thought I'd
have a look at them today. It was then that I examined the leaves - they
are lanceolate, glabrous under a x10 lens, and around 16 cm long and 5
wide. The stems are over a metre long. That probably makes it A.
tabernaemontana, a cultivar of it, or possibly a hybrid.

It will be interesting to see if the flowers vary between the green and
pink-stemmed plants.



I have grown Amsonia tabernaemontana in the past, though not from seed.

Having googled for images, I am finding that pics of A.t. have green
stems. However, pics of A.t. var 'Salicifolia' show brownish purple
stems. I wonder if what you are seeing is your A.t. showing signs of
the colouring that created A.t. var. 'Salicifolia'?

Do let us know how the seedlings develop, please.

--
Spider
On high ground in SE London
Gardening on heavy clay

On 27/09/16 18:31, Spider wrote:
On 27/09/2016 16:59, Jeff Layman wrote:
On 26/09/16 18:59, Nick Maclaren wrote:
In article , Stewart Robert Hinsley
wrote:

The obvious explanation is that the parent plant is heterozyous
for stem anthocyanin (or other pigment, but google provides a
citation for the presence of anthocyanins in Amsonia)
production, and a proportion of the seedlings are homozygotes
for the recessive allele. Perhaps you'll later find a
pleiotropic effect on flower colour.

For every complex problem there is an answer that is clear,
simple, and wrong :-) That may be the explanation, but it may
well be mistaken. If the flower colours are different according
to the stem colour, I agree that would make this fairly certain.

The expected mean ratio of offspring from a self-pollinated
diploid dominant/recessive heterozygote is 3:1. 50:10 isn't
that far off 45:15 - you'd need someone with more current
statistical expertise to say whether the difference is
statistically significant for a sample of that size.

Current, I can't do, but I don't need it. That is the mean
ratio ONLY if it is a single, Mendelian gene AND the parent
reproduces purely by haploid/diploid self-pollination. In my
previous post, I missed that it was a single parent, so said
something irrelevant. I agree that is the simplest plausible
explanation. Anyway, as I said, 50:10 isn't significantly
different from 45:15.

I'm sorry to say I have been wasting your time. The plant I have
is *not* Amsonia hubrichtii (although that's what it said on the
seed packet). It has a number of almost ripe seeds heads and I
thought I'd have a look at them today. It was then that I examined
the leaves - they are lanceolate, glabrous under a x10 lens, and
around 16 cm long and 5 wide. The stems are over a metre long. That
probably makes it A. tabernaemontana, a cultivar of it, or possibly
a hybrid.

It will be interesting to see if the flowers vary between the green
and pink-stemmed plants.



I have grown Amsonia tabernaemontana in the past, though not from
seed.

Having googled for images, I am finding that pics of A.t. have green
stems. However, pics of A.t. var 'Salicifolia' show brownish purple
stems. I wonder if what you are seeing is your A.t. showing signs
of the colouring that created A.t. var. 'Salicifolia'?

Do let us know how the seedlings develop, please.

This is from Rick Darke's article in The Plantsman (June 2005).
Amsonia tabernaemontana var. salicifolia:
This variety differs from the typical species in its narrower,
consistently lanceolate, glabrous leaves giving it a willow-like appearance.

Of Amsonia tabernaemontana itself, he notes "The lanceolate to broadly
elliptic leaves are typically 7.5–10cm long, up to 2.5cm wide and often
finely hairy beneath.

My plant's leaves are up to 5 cm wide.

As far as I remember, my plant took quite a few years to flower from
seed, but I'll keep and eye on it.

--

Jeff