In a message dated 7/31/11 6:46:38 AM, Theo Sanders writes:
The chips developing little bulbs shall be treated with oryzalin for > chromosome doubling.
Hi Theo,
What concentration of oryzalin are you using?
Do you add DMSO to it?
At what stage do you apply it (such as immediately after cutting), or do you wait any period of time before oryzalin treatment?
The tetraploid and hexaploid tazettas I developed from using colchicine back in the 1980’s (when I actually had the time for this sort of thing!) were produced using twin-scales.
I copied the published technique of Dr Chris North (Scottish Horticutural Research Instutute) who successfully converted to tetraploid a number of poetaz varieties such as Cragford.
Immediatley after cutting, I applied a drop or two, as needed, of 0.1% colchicine solution (no DMSO though) down in between the two scale layers of the twin scale, to treat the tissue in between from which the bulblets will later arise. These were allowed to sit overnight (or up to 24 hours), then they were soaked for a half hour in a fungicide such as chlorothalanil and then put into bags of slightly moist vermiculite (just the standard twin scaling procedure). One thing i did notice with vermiculite is that the coarse type usually available here stays too wet, it is the more fine-grained form that works by far the best.
Best wishes,
Bill the Bulb Baron (William R.P. Welch)