RE: Seedling Numbering Systems/Chromosome Counts
- To: email@example.com
- Subject: RE: Seedling Numbering Systems/Chromosome Counts
- From: tlittle@Lanl.GOV (Tom Tadfor Little)
- Date: Fri, 26 Jul 1996 08:44:26 -0600
:Is there a good reference which explains the chromosomal relationships
:between the various bearded and non-bearded irises?
The chapters toward the back of _The World of Irises_ are still probably
the best starting place for this sort of information. I also posted a
message to the list on this subject ("A little chromosome essay", March 8)
which you can find in the list archives on the web.
:How do I go about determining the ploidy (is that a word?) and the
:chromosome counts of any existing named varieties of bearded or non-bearded
:irises that I may wish to grow and someday use in a breeding program?
A few have been counted and reported in iris society publications; some
are indicated in the registration data. In many cases, you have to infer
the chromosome count from the parentage. In principle, this involves
laborious pedigree research. In practice, with a little knowledge about
the chromosome groups involved in breeding the class of iris you're
interested in, it's usually pretty trivial. For example, virtually all
TBs introduced since the 1940s are tetraploids with 48 chromosomes. The
more you read, the easier the inference becomes.
:Also how does one go about tracing the pedigrees for various irises?
The AIS publishes official checklists for each decade. With a complete
set of checklists, you just look up the iris, then look up its parents,
then grandparents, etc., working backwards until the data dries up.
Tom Tadfor Little firstname.lastname@example.org -or- telp@Rt66.com
technical writer/editor Los Alamos National Laboratory
Telperion Productions http://www.rt66.com/~telp/