Re: Re: CULT: ROT: Is it genetic?

My reservations on the genetic disposition toward rot stem from my
experiences with growing irises and my background on raising cattle.

If it were a simple matter of dominant vs recessive traits at the genetic
level, then it would be relatively easy to select against.  But, and it's a
major but, if on the genetic level it involves the interaction of genes,
then it could be confoundedly convoluted in how it actually works.  My
experience indicates it is not simple.  If, e.g., some combination of genes
makes an iris susceptible to rot in wet conditions in heavy clay soil,
suppose that same combination makes it resistant in a sandy situation.
Partial dominance of genes and how they act when combined prevent ruling
such scenarios out altogether.  When you mix in the myriad factors that
influence how an iris may or may not grow in conditions and how that genetic
interplay may help or hinder its growth, then it would seem unlikely that
selecting by the hybridizer is going to have a lot of impact.   Add to that
the possibility that more than a single gene and combinations thereof may
dictate how a plant reacts and the can of worms just gets worse.

With the genetic makeup existing in almost any iris you choose, combining it
with any other iris could result in a wide array of how it performs on its
home ground, much less when it gets exposed to the variability of numerous
gardens.  If things like weather conditions, trace minerals, soil nutrients,
drainage, soil texture, sunlight etc. may effect how that interplay of the
genes manifests in the growth and health of the plant depending on the combo
of genes it has inherited, then not even siblings from a cross would
necessarily perform the same.

And they don't for me.  Nor do cultivars always behave the same.  A poor
grower can turn into a good one just by moving it.  Or, sometimes, simply by
leaving it alone in place for a period of time.  Moving one can change
everything, even when I can't discern any real difference.  Moving one can
also make a world of difference when the growing conditions are altered
significantly.  They can also have a string of good seasons, then start to
dwindle and nothing alters that path.

My benchmarks for good, solid growing irises are the old homestead iris and
the grandmother irises.  They have been in place for decades.  But even they
can be affected by changing conditions.  They can also do new tricks, like
nearly dying off when it gets bad enough.  The first time that happened, it
was unexpected and a complete surprise.  Here were plants that could
seemingly take anything and then they sulked and nearly disappeared after a
move.  Subsequently, they got moved again and despite more or less constant
neglect, thrive again.  But currently even those are on hold for growth.  I
have no more now than I had after bloom last season.  It's a sad measure of
just how troublesome the season has been.

These are my current opinions based on what I've seen.  My thoughts on
things change from time to time.  Currently I just think the genetic
disposition will not prove a feasible method of curbing or eliminating
rot....or some other maladies.  I do think it is likely a factor, but I
don't think it simple enough to draw any broad conclusions from.  Perhaps my
conditions are too variable for me to draw a bead on it.

Donald Eaves
donald@eastland.net
Texas Zone 7b, USA



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