How to differentiate between 2N, 3N and 4N?

[Nelson Wong]

How do we know or differentiate if an orchid is a 2n, 3n, or 4n? are there any characteristics? or do we have to actually do a test?

 

[NYEric]

Visually, increased ploidy plants exhibits thicker leaves, and the foliage is almost imbricated. They are usually slower growing but better shaped blooms.

 

[Nelson Wong]

do you have an example of imbricated foliage? some visual could help

 

[NYEric]

Not me but see if there are photos of 4N plants on this site or on Orchids Limited's site.

 

[CharlesD]

You would have to do some research but for Cattleyas at least there are flower characteristics (beyond just being bigger) that indicate polyploidy. Look at Roy Tokunaga’s writing in the AOS magazine or look up papers by haruyuki kamemoto also don wimber. Without counting chromosomes the breeding behavior of a plant will help you differentiate. Eg 3N being mostly infertile. Sometimes diploids will breed readily but the offspring may not be fertile depending on the other parent. 4N plants will dominate the other parent if bred to a 2N. There’s a lot info to dig into about ploidy

 

[big923cattleya]

4N Cattleya seedlings or plants, with which I am the most familiar, are indeed slower growers, I agree that they often show thicker leaves, rounder leaves and they typically produce flowers with heavier substance. The color of the flowers is often deeper, richer. As seedlings, they often show several new leads at once rather then just one or two.

They could be larger but that is often controlled a bit by culture. If you grow a 4N Cattleya poorly, something tells me that the flowers are not automatically larger.
I agree, unless you run a dna test, how could you possibly know for sure. But like I said, you have to grow them well.

 

[littlefrog]

Indicate only... The only way to know for sure is to count the chromosomes. Problem is if you do a visual analysis you have to compare to a known standard. To get a known standard you need to count. Anything short of that is guessing. Perhaps educated guessing, but still guessing. Breeding behavior is a pretty good indicator, but that takes years to figure out... Longer than I have.

With phrags it is kind of a shorthand to guess that something is polyploid based on the presence of extra tissues or 'teeth' on the flowers.