North American Fruit Explorers mailing list at ibiblio

[dwoodard@becon.org]

--- In nafex@egroups.com, Claude Jolicoeur <cjoli@g...> wrote:
> Douglas,
> I was reading in more depth your well documented note on hardy 
apricots and
> a few questions raised...
> 
> 1. Are P.mandshurica and P.sibirica really different species from
> P.armeniaca or simply strains? 
> 
I actually know very little about this, but I have noticed that 
authorities seem to differ; some treat them as species and some as 
subspecies or botanical varieties.

> 2. Other than cold hardiness, are there important difference 
between them?

Again, I am confident of very little. I have a vague impression, and 
I am not sure whether it was formed from reading direct statements or 
from inference, that P. sibirica is a smaller tree, has poorer fruit, 
greater coldhardiness (resistance to deep cold) and less 
susceptibility to dormancy problems that P. mandshurica. I understand 
that P. sibirica has been favoured on the prairies as an apricot 
rootstock. Possibly the Morden station would know of a source of P. 
sibirica, or possibly Arthur Coutts (or his son)(A. W. Coutts, Box 
539, Unity, Saskatchewan  S0K 4L0).
> For instance, you wrote :
> >I understand that Scout has tended to have dormancy problems in 
the 
> >East which makes me suspect that it may have some P. mandshurica 
> >ancestry.
> Does this mean that there is a fundamental dormancy problem with
> P.mandshurica in the East?
> 
Yes, very definitely. I have not grown either P. mandshurica or P. 
sibirica, but this has been reported by others, including Ken 
Taylor's comments to me. I was told by the Vineland station (seven 
miles west of me) that they had tried to keep Scout and Sansin (both 
Manitoba-hardy) in their collection (they bred apricots in the past)
but found it impossible, especially with Sansin. The trees had no 
problem with our deep cold in this commercial peach growing area, but 
they could not take the cold weather following long warm thaws in 
late winter. An extreme example occurred in the winter of 1980-1981. 
I was living on Amherst Island near Kingston at the time. We had 
minus 25 or 30 F. just after Christmas which did not seem to bother 
some young Harrow apricots that I had. In February we had a thaw 
lasting 2 or 3 weeks during which day temperature peaks got close to 
50 F. In March we had a cold snap with temperatures down below zero 
F. My apricots couldn't take this and the branches started to shrivel 
up and the trees died. P. mandshurica will take very little of this 
kind of stress; it is a sucker for thaws. As I mentioned, there is 
one recent cultivar which has a reputation for being more resistant 
than the others, but I am not sure which one it is.

> 
3. In my notes, I had Scout listed as a Manchurian seedling, which 
goes
> with what you suspect (above), but then Brooks and Olmo would be 
wrong. Or
> maybe the explanation could be that if Manchurian is a strain of
> P.armeniaca, then Brooks and Olmo would also be right???
> 
I get the impression that fruit authorities get things wrong from 
time to time. Maybe Brooks and Olmo made the mistake, maybe it was 
Woykoff, maybe a translator or some other intermediary. There are 
lots of opportunities to make mistakes in this kind of work; 
including relying on memory, one's own or other peoples', when one 
should not. Maybe Woykoff reported (sheer speculation) that he was 
sending seedlings of a cross in which the seed parent was P. 
armeniaca and this got garbled to both parents being P. armeniaca.

Whether species or strain, there is a difference in dormancy.

> Thanks, Claude
> 
> ---------------
> A 14:28 00.12.11 -0000, vous avez écrit :
> >Claude, have you tried Westcot and Morden 604? They were both bred 
at 
> >the Agriculture Canada station at Morden, Manitoba in Agriculture 
> >Canada zone 3b and have been reported successful by several people 
in 
> >cold areas of Eastern Canada. They have Prunus armeniaca ancestry 
(or 
> >mostly) and are not unusually prone to dormancy problems. [....]

I have read or been told some time ago that Central Asian P. 
armeniaca are relatively resistant to dormancy problems but tend to 
be susceptible to brown rot. I have also heard that the P. armeniaca 
from Hunza (N. Pakistan) tend to dormancy problems in eastern North 
America.

Douglas Woodard     dwoodard(at)becon.org     (905) 682-4349
56 Maple Street, St. Catharines, Ontario  L2R 2A9


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