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Essay on Culls from Tissue Culture (Introduction)

Dear Group,

As promised, and because there is a little LULL in e-mail traffic and
things are getting a little DULL, thought I would MULL over some ideas
that we discussed previously...that of CULLS from Tissue Culture.

Several points of view were expressed in recent e-mail posts on TC and
OS. The general impression I received is that there is a wide range of
differences of opinions about tissue culture and the plants that result.
I must remind all that opinions are just that....opinions, including my

The discussions reminded me of the conflicting opinions I read 12 years
ago in the 1986 Spring Edition of the Hosta Journal (see "Close-Up on
Tissue Cultured Hostas" and a written debate "Cultivar or Clone", both
by Warren I Pollock, Editor, Hosta Journal, Vol 17,No.1).Various
"experts" presented their views...one of which made me realize how wrong
he was. He described plants which were "merely tc-ed progeny and not
vegetatively produced divisions". This expert stated that it was his
contention that "because of the chemicals and techniques used in tissue
culture which "encouraged" the production of sports and variations, that
it is improper to classify tissue culture as a vegetative method of
propagation which produces offspring which are in all respects identical
(i.e. clones) to the plant from which they were produced." 

IMHO, this expert has been proven wrong by the many studies made on the
origin of Chimeras and by practical and experimental experiences in TC
to date. If my opinions are not convincing to readers, I suggest you
read, better yet, study the reference documentation which will be
presented at the end of this essay. You will become convinced as I have

I have arrived at the conclusion that hosta plants from TC are indeed
divisions. I have expressed these views in "Mid-Winter Hosta Musings"
(see Hosta Journal, Vol.25,No1.pg44) In it, I attempterd to make the
case that it makes no difference whether:

   1. a nurseryman digs a huge clump with a tractor and a backhoe and   
chops them up with an axe or

   2.a gardener digs small clumps with a shovel and separates
divisions    with the tip of a machete or

   3.one Rossizes hostas still in the ground or in pots or

   4.one propagates hostas from leaf bud cuttings or

   5.one transfers proliferations of meristems from tc media into      

that all of these methods are types of vegetative propagation in which
there are no changes either in the nuclear or cytoplasmic genetic
characteristics transferred from parent plant to the tc liners.

Before getting into a discussion of what are culls, off-types, rogues,
sports ot whatever one wishes to call them, let me brifly address the
'problem" we are discussing.

I personally know dozens and dozens of "growers". Among them, I know of
three who have expressed their personal views that hosta tc liners are
not as represented by TC labs, are very variable in their appearance,
are not vigorous growers and that their customers are dissatisfied with
them. I consider this anecdotal type  evidence of an expressed problem.

I can present as many non-growers and customers representing similar
anecdotal type evidence that they are happy and delighted  to be able to
purchase juvenile plants of known cultivars at low tc prices. While
there may be occasional incidences of known poor vigor or other
detrimental characteristics, I know of none in this group who attribute
these problems to the method of propagation but rather to the 
characteristics of the cultivar, itself.

One must look to the motives of the growers as well as those of the
non-growers for clues of why they believe as they do. The motives of the
two groups are different, thus their views about tc plantlets are
different. Personally, as a collector and breeder, I am delighted to
find the rare examples of sports from tc because they represent
possibilities for new and exciting genotypes and phenotypes of hostas. I
know of some who shop weekly at garden centers looking for off-types,
culls and sports, especially streakies which represent potential breeder
plants. I wish I could find them myself. Many of the most famous hostas
today are tc sports including 'Striptease', 'Guardian Angel', 'Lady
Isobel Barnett', 'Patriot','Guacamole', 'Winter Snow' and 'Ferris
Wheel', so what is so bad about culls anyway? There certainly are
tradeoffs which I have just identified. 

Now this is just the introduction to the Essay, folks,. I haven't gotten
into the what, why,  how and the who of it all. But I will get to it in
a later post. So if you will forgive me for now, I'll break it into
several pieces and resume later. OK?

Jim Hawes Oakland Md

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