Genetic Susceptibility to Rot

David Silverberg wrote:

:  Someone asked what makes certain iris rot when no others will.  If we
:  investigate the hybridizer and his practices you will find that in many
:  instances that there is a lot of line breeding ( iris incest if you will
:  !!!).  Continued practice will alway magnify the weak spots in the genetic
:  character, as with the classic biological case studies of the Jukes and the
:  Kallikaks (sp?).  I may be right or I may be wrong.  COMMENTS?????

"Never say 'always' or 'never' ! " -- Herb McKusick

I certainly agree that too much line-breeding can lead to problems, just as too
much out-crossing can make it difficult to recover desirable traits.  The
"secret" to success is maintaining an appropriate balance.

In this case, I think it depends a great deal on whether the hybridizer has been
consciously selecting for rot resistance.  After doing so for many years, I've
found I have better results from crossing clones that are "cousins" (sometimes
rather distant ones) than from crossing to either sibs or half-sibs or from
crossing "unrelated" ones.  

Next question for the opinion poll:  how distant must the relationship be, for a
cross to be considered an "outcross"?

Sharon McAllister (73372.1745@compuserve.com)
Coping with monsoon season in southern New Mexico
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