Originally Posted by thefish1337 (Post 943521)

I was looking into the literature surrounding the "runt" hypothesis that Roy has put forward. For reference he also is generally referencing looking through mericloned seedlings to find the polyploids arising from this cloning technique (in the context of his personal anecdote). This allows you to find one "type" of tetraploid as there is multiple mechanisms that result in a duplication of chromosomes. There is documentation that colchicine induced tetraploids in some plant types results in dwarfism and these plants have some disregulation with plant hormones because the doubling of the chromosome increases the amount of a regulatory mRNA which disrupts the signaling pathway. Additionally, runts may also be >4n which also results in other types of regulation of growth, so that precious tetraploid you think you have could just be a crazy chromosome mutant that will be cruddy its whole life.

Which is to say, all polyploids are not created equal and you are better off culling any weak plants, plants that lack characteristics of vigor, ect. than hoping for a rare tetraploid, which may or may not have anything good about it. This is why breeders have moved to oryzalin and colchicine treatment of protocorms because you can generate a lot of tetraploids with select plants and then select the best ones. This results in significantly more "useful" plants compared to the old needle and the haystack approach.

Originally Posted by Orchidtinkerer (Post 943537)

I have no knowledge of what 4N means even though I have some 4N seedlings - from what I have just read here it causes slow growth, dwarf plants, mutated flowers and has been forced onto some plants via some artifcial chemical.
I am well aware that is not going to be the true story, I though 4N made a plant stronger - I have a bit of understanding of plant biology from school but we never covered 4N!
Can I ask if someone knows does it actually occur naturally or is it something man-made?

Originally Posted by Jeff214 (Post 943547)

Oh im jealous of those seedlings! I emailed and called H&R a few times but I never got a response from them. Hope they do well for you!