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Re: [nafex] With Malus aforethought

1) The hybrid between Malus fusca and the common apple, M. Xdomestica, is classified as M. Xdawsoniana.   The fruit of M. Xdawsoniana is as described -- definitely not fusca-like.   Bark differences are exactly as you describe, Rick.   Leaves too are distinctly different -- usually strap-like, much more similar to common apple than to Malus fusca.
2)  I agree that the wild species is being diluted very rapidly now in the southern part of its range (but not in the northerly stretches). Fortunately the species has been explored rather well by the USDA repository at Geneva.  A diverse selection of the germplasm is now grown there, and, I believe, seeds have been stored  at Boulder.
3)  The fire-blight resistance of Malus fusca was mentioned earlier;  the species is not resistant.  We ran quite extensive tests of Malus fusca  back in the 70s and 80s, working with several seed accessions.  About 25% of the seedlings were very resistant to blight, about 25% very susceptible, and the balance of intermediate susceptibility.
    On the other hand, in parallel tests with the collar rot pathogen, Phytophthora cactorum, Malus fusca  seedlings were 100% susceptible -- perhaps the most sensitive of any set of seedlings we ever looked at.
    In general, both Malus fusca  and M. Xdawsoniana  are sensitive to at least some of the common latent viruses.
    All in all, Malus fusca  doesn't seem too promising in a breeding program.  I did use a couple of the blight-resistant selections in the rootstock breeding program some years ago, crossing with Malling 27 and M.9;  when all those hybrid seedlings were killed in our collar rot testing, though, we got somewhat discouraged with the cross.



rick valley wrote:

Lon says:
>Are you sure you are looking at Malus fusca, Rick?

OK, I'll be serious- here's what I have seen: in many locations, abandoned
field and hedgerow trees, with fruit having many characteristics of Malus
fusca; yellow with a rusty blush on one side, and clustered. I reckon pure
fusca to have fruit @ 1 cm long, oval. Now often the size is larger-
typically 1.5 -2 cm. and they may be round rather than oval, and the clusters
are usually smaller in number of fruit, not a whole handful like with pure M.
fusca. (I suspect I am acquainted with some populations of M. fusca that were
highly selected by native people) The bark is often not such an ash grey and
scaly as pure fusca. I figure these trees are F1 fusca/apple crosses. I knew
one tree that was maybe a back-cross to apple; color pure fusca, round, 4
cm+, clusters of 2-3, juicy, tart, would have been a super tart cider apple,
the tree was GROANING with fruit. It's gone now. Many of the suspected
hybrids I know are in typical M. fusca habitat. I've talked this up with Ken
Priddy and Larry McGraw who've echoed my thoughts on it, Ken knows of many
hybrid crabs, but I haven't asked Pierre. With insect pollenation, and easy
inter-fertility and humans tearing out scrubby woodland and fencerows, I
think there is terrific pressure on Malus fusca. Of course, this is
speculation by someone w/o science training, I haven't done any DNA
sequencing, but it's what I see happening. And I'll be a geezer soon, now, I
turn 50 this year. (Well, I was serious for a little while)

> I keep seeing lots of
>other crab apple species, but very few M. fusca hybrids.  I've seen lots of
>M. fusca in wet areas where other apples are unable to grow, though.  I
>think that will help keep the species pure.  Also a reason it should be
>looked at more closely - M. fusca can grow in wetter soils (I've seen them
>growing partly IN water) than any other apple and according to Dr. Westwood,
>is the most resistant to fireblight of all apples.  Pierre Rotschky in
>Vancouver, WA has done a lot of study of the species and can tell more than
>I, though.  I don't think he is a computer user, though.  He has told me of
>some interesting local blueberry species he has found  that I keep meaning
>to go see and haven't made it yet.

Those blues sound interesting!

Lon; I think I could sell quite a bit of Malus fusca seed with a bit of help
locating it and timing the harvest. the wetland nursery folks I know can't
get enough seed. That'd help preserve the species!

Rick Valley Northern Groves
PO Box 1236, Philomath, OR 97370
Mobile-(541)602-1315, hm.& msg. (541)456-4364  Bamboo catalog $3 or at
"Useful Bamboos and other plants? Permaculture education? Ecological design &
consultation centering on water,landform and horticultural systems"

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