echinosum says...

K;787276 Wrote:
echinosum writes-
But Bramleys are not in that "most of the time" bit. Bramleys need
to-
be cross-pollinated by TWO different apple trees. So you need at -
least-
two other different apple trees in flower in the vicinity at the -
same-
time to get your Bramley to fruit.

Are you absolutely sure of this? I've just gone back to 3 of my
references and they all agree that the second tree is to pollinate the

pollinator, that the Bramley only needs one to pollinate it. But my
knowledge of genetics is too rusty to argue one way or the other.
--
Kay
No, I'm not absolutely sure. I have only self-education in
biology/horticulture. The wikipedia article on polyploidy is unhelpful
on the matter. But I have always wondered what kind of weird sex is
going on if three partners have to come together, I've never heard of
that happening in general. So I am very attracted by the theory that
the third is only to pollinate the second, which is repeated at many
sources.

But the most reputable horticultural sources I can find seem (emphasis
on seem) to say that two varieties are desirable (desirable, perhaps
not entirely necessary) just to pollinate the triploid:

Brogdale http://tinyurl.com/3frvhj says "To produce fruit the triploid
will need two pollinators" (that seems definitive, no fruit on the
triploid without two pollinators, and Brogdale is our national apple
archive)

RHS http://tinyurl.com/4b4lmz
says "Some cultivars are triploid ? they have sterile pollen and need
two other
cultivars for good pollination" (actually you could read that both ways
- good pollination of what - but the plain reading is that two are
needed for good pollination - note good pollination - of the triploid)

Keepers Nursery http://tinyurl.com/3twqk2 says "Bramley's Seedling is a
triploid variety and should be grown with two other pollination
partners" (again you could take that both ways as with RHS - Keepers
Nursery has the largest number of apple varieties of any commercial
nursery)

The BBC say two for the triploid too, but I don't consider them
reputable.

Searching the web, I found one lady who posted on a forum with a
problem. She had a triploid, and cut down one of the two pollination
partners. The next year, she only got "crabs" on her triploid. Perhaps
it was a bad year, perhaps the one she left wasn't a good pollinator
for it. Who knows. No one answered her post. She didn't update us the
following year, at least not on that thread.

This source http://tinyurl.com/4p9gpy points out that an experiment in
1938 by Crane and Lawrence found 5% self-fertilisation on triploids,
which is more than on most diploids. Which rather goes against the
received wisdom. What is going on? The same source goes for the third
to pollinate the pollinator theory.

This source, which seems well-grounded in real life practice in the
orchard, goes for the third to pollinate the second theory.
http://pollinator.com/effecpol.htm But it makes an interesting point
about an individual fruit needing to be well pollinated in order to
grow large, in other words apples, unlike people, can be half pregnant.
So perhaps that is what the third variety is about, and why the lady
above got small fruit on her triploid.

btw, I was wrong in saying that Cox's Orange Pippin is a triploid, it
isn't. It was Blenheim Orange that I had in mind.

Interesting reply. It looks like I will have to wait and
see if my young Bramley apple bears any fruits. It has
flowers now and there is one apple tree nearby also in
flower. The neighbours also have apple trees, so I'm
keeping fingers crossed.
--
David in Normandy.
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