HYB - SI-JI: Reg. 7 Irisarian Reprints #18

> A series of articles reprinted from the Region 7 IRISARIAN with myself as
> Editor in 1990-91.  [Gary Sides--Jan. 1998:  Posted to Iris-L]
> 
NOTES ON HYBRIDIZING SIBERIAN AND JAPANESE IRISES 
Currier McEwen    So. Harpswell, Maine
	    
These notes will be somewhat general but, as Gary Sides has suggested,
chiefly concerned with my own program.  Hence they are limited to Siberian
and Japanese irises (J.Is).  The general principles of hybridizing them
are, of course, like those for all irises but with one important
difference.  Most crosses of the bearded irises are made after the bud has
opened but this cannot be done with Siberians or J.Is if one wants to know
the pollen parent.  This is because the anatomy of the blossoms is such
that any opened flower has very likely been crossed by an insect or even
the wind.  Hence the bud at balloon stage (due to open in a few hours) is
opened by hand, the anthers carefully removed with forceps and the falls
then brought up and fastened so the stigmas are safe from any foraging bee.
 Hours later or next day when stigmas and anthers are mature, the flower is
opened, crossed with pollen of the other parent selected for the cross
(which had been prepared in the same way), the falls fastened up again and
the tag tied on.  Also, in these days when both Siberians and J.Is exist as
diploids and tetraploids one should select diploids to cross with diploids
and tetraploids with tetraploids.  Theoretically a mixed cross can succeed
giving a sterile triploid but it is scarcely worth the effort.
	    
Of course many fine cultivars, such as that all-time great, WHITE SWIRL,
have come from wild crosses in which only one, or perhaps neither parent is
known but obviously much surer progress can be made by having goals toward
which one chooses to work and selecting parents that seem like good bets
for those purposes.  Every hybridizer must decide on his or her own goals. 
I started merely crossing flowers that I particularly liked but gradually
definite goals evolved.  Currently, with both Siberians and J.Is, I am
working for new colors, existing ones closer to true color, better
branching and bud count, miniatures, repeaters and continuing bloomers,
vigor and resistance to disease.  I should add fragrance to this list but
so far have had no success.  Of course I would especially urge the beginner
with these flowers to be interested in fine form but in this to have
concern for a variety of forms, the traditional more dainty flowers with
arching falls as well as the currently more popular ones with round,
flaring form and overlapping falls.  All these goals apply, for me, to both
Siberians and J.Is.  In the case of the latter I have one more:  the
development of plants that will do well in neutral or even alkaline soil
and also have less need for water.  (I would like to hear from any reader
who would be interested in joining in this effort and who has lots of space
and alkaline soil.)
	    
In these days of both diploids and tetraploids I urge working with both.  I
have a somewhat special interest in tetraploids because they have been "my
thing" but it would be sad if interest in the diploids should diminish and
I work avidly with both.  Especially in the case of the J.Is, the
tetraploids offer new potential.  One of my Japanese friends has remarked
that with 500 years of hybridizing J.Is in Japan much of their potential
must have been exploited and the tetraploids open up a new challenge.
	    
I started growing tall bearded irises and daylilies about 1954 stimulated
by the lovely pictures in a Schreiner's catalogue.  The catalogue also
urged joining AIS.  I did and the first issue of the Bulletin I received
had in it two articles about hybridizing.  That sounded great to me so I
began and made my first crosses in 1956.  In 1960 a medical meeting took me
to Chicago and while there I had the temerity to phone David Hall and
Orville Fay and visit them.  Both were most kind to this very green
beginner.  Fay was then well on with his use of colchicine and explained
how he used it to convert his diploid daylilies to the tetraploid state.  I
was fascinated and began to try it as soon as I got home - which then was
in the Riverdale section of New York.  That was when I switched from tall
bearded irises to Siberians and J.Is.  The TBs had become tetraploid in
nature and so were not a challenge but that was not known to have occurred
in the beardless irises.  I was lucky with the Siberians and had some
induced tetraploids within a few years.  However, such first generation
tetraploids can revert to the diploid state and I did not introduce the
first tetraploid Siberians until 1970 when I had two second generation
ones, ORVILLE FAY and FOURFOLD WHITE.  Success with the J.Is was much
slower and for years colchicine treatment gave me only chimeras (partly
diploid and partly tetraploid)  and when they were crossed only diploids
resulted.  Finally however, I had advanced generation tetraploids and
introduced the first, RASPBERRY RIMMED, In 1979.
	    
When we lived in New York my space was limited to two beds each about 20 x
30 feet but when I retired in 1970 and we moved to what had been merely a
summer home in Maine, space became ample.  I now have about an acre of iris
beds with a total of several thousand Siberians and J.Is.  I put out about
500 to 700 combined Siberians and J.Is yearly and each fall must empty the
three year old hybridizing beds to make room for the next year's seedlings.
	    
Our Siberians at Seaways Gardens are at peak about mid-June and the J.Is
mid-July
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