4088Ploidy in plants... and people too!
- Dec 1, 2005Hello all,
There are only two conclusive ways to determine IF any species is
tetraploid. Well... one for sure (karyotyping) and another (GC- Mass Spec)
will confirm it and tell you the size of the genome as well. The first
method is simple... staining the chromosomes and making a karyotype. This
has been done with some azaleas. For reference see:
Li, Hui-lin. 1957. Chromosome Studies in the Azaleas of Eastern North
America. American Journal of Botany 44:8-14.
Sax, Karl. 1930. Chromosome Stability in the Genus Rhododendron. American
Journal of Botany. 17: 247-251.
The second method... GC-mass spec literally counts the number of base pairs
of each chromosome as it passes through an extremely small pore. It will not
accurately determine if the plant is tetraploid because you must first have
an image of the chromosomes to see if there are identical chromosomes
present (hence tetraploid). Together, both methods would give a very
accurate measurement of ploidy and genome size.
Hope this helps. Just keep in mind that guessing on ploidy is a tricky
business. Wheat is a great example. Wheat is a synthetic hexaploid yet is
neither more vigerous than its ancestors nor self/cross incompatable despite
having sets of chromosomes from a vast array of the Triticum genus.
Peace be with you all.
Matthew R. Chappell
Georgia Agricultural Experiment Station
Horticulture Dept.- Plant Breeding & Genetics
1109 Experiment Street
Griffin, GA 30223
Office- (770) 229-3369
Cell- (770) 715-6585
From: firstname.lastname@example.org [mailto:email@example.com] On Behalf Of
Sent: Thursday, December 01, 2005 3:16 PM
Subject: Re: [AZ] Doing crosses with Rhododendron occidentale?
I just repotted a few seedlings of a cross of Rh. atlanticum and Rh.
luteum that a friend in California made. I think both are probably
Mike Creel, Zone 8A, SC
This study reported R. atlanticum as diploid and a single triploid.
There must be tetraploids elsewhere.
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