Title: “Colchicine induction of ‘Old Blush’ 2n pollen for the hybridization and breeding of tetraploid rose”
See:
Wow, this is fascinating!!! Hmm. I wonder if we’d have even better success using trifluralin or oryzalin as they seem to be more effective against plant microtubules and at lower concentrations. I have to think about which diploid parents I may want to try this on.
Thanks Henry for passing along the paper. This seems more doable for a person than trying to get more 2n pollen through laughing gas or other means people have tried.
Forgive the newbie, but say if David used his Candy Oh! Vivid Red and doubled the chromosomes. Would it change any of the characteristics of the plant, or would the pollen just change?
If you doubled the chromosomes of the whole plant then yes, there’d be some differences, often bigger/thicker/stiffer parts as the cells are bigger.
You don’t necessarily need to double the whole plant to get reproductive parts of a higher ploidy though (as shown in the paper where they were just injected flower buds)
Colchicine, and probably other substances, sometimes do not work as neatly as we may suppose. For example, Traub (typed manuscript) injected colchicine into the old daylily clone ‘Europa’ (3x). This resulted in yellow-flowered sports in a clone that has been remarkable unwilling to mutate in any way in the past few centuries that it has been spreading around the world. No seeds, but the darned thing spreads just the same, and always just the same.
http://bulbnrose.x10.mx/Heredity/Traub/TraubHemerocallis.html
In addition, “colchicine sports” are rarely mentioned these days, but were discussed in the “olden days” (before my time). These occur when chromosome-doubled cells “decide” to slip in an additional cell division, returning them to their original ploidy. Thus, a diploid cell becomes tetraploid for a few rounds of mitosis, then does a somatic meiosis, resulting in four diploid daughter cells that are not quite like the original.
http://bulbnrose.x10.mx/Heredity/PickardRabbit1929.html
http://bulbnrose.x10.mx/KKing/SomaticSegregation.html
This is really interesting, thanks Dr. Kuska.
How do I implement this using available materials which, for me, are winter crocus bulbs I bought last fall when I was contemplating yet again trying something like this? Shredding the bulbs in a blender is an obvious route, but does anyone know how much bulb to use with how much water?
I can see a practical problem with this, too, in that the technique is a bit of a numbers game which the amateur breeder might not be able to play. Between killing a lot of pollen in the bud, so to speak, by overdose and the relatively low transformation rates even when successful you would need to screen a lot of seedlings to find one that’s been derived from doubled pollen grains. It might be easier to try old fashioned bud transformation which gives some predictable morphological cues.
Never forget that colchicine is poisonous to humans as well as to plants.
According to the IPCS Inchem entry on Colchicum autumnale:
All parts of the plant contain toxins. The greatest concentration of toxins is found in the seeds and the bulb (corm) (Cooper & Johnson, 1984; Frohne & Pfänder, 1983).
Colchicine is present in the flowers (0.1 to 0.8% in fresh flowers; up to 1.8% in dried flowers), in the seeds (0.2 to 0.8%) in the bulb (corm) (0.4 to 0.6%). The leaves contain very low amounts of colchicine (Gessner & Orzechowski, 1972).
And in Toxicity of Houseplants by David G Spoerke Jr and Susan C Smolinske we learn that, “…as little as 20 grams of G. superba tubers provide 60 milligrams.” That’s Gloriosa superba, the beautiful Gloriosa lily.
There are more links here: Chemicals in Plant Breeding