trifluralin applied to diploid rose pollen may produced tetraploid seedlings with tetraploid mothers

It may be possible to use diploid rose pollen with tetraploid mothers and get tetraploid offspring if this technique that works with maize also works with roses.


Hi Henry,

This is a great idea. We had a nice thread about this in the past.

I’ve actually tried it a number of years ago in a pretty complete experiment with several replications of each treatment. I used Carefree Beauty as a female and from the top of my head diploid R. macounii as a male as well as the tetraploid R. palustris from the arb too. I can go back to my records to see if I used other males as well. I wanted to use one time blooming species because of non-recurrent bloom as a phenotypic marker.

I applied trifluralin to the stigmatic surface at different concentrations with a brush. I then pollinated them with this pollen. Roses have binucleate pollen at maturity rather than trinucleate like maize. Kato applied trifluralin to the developing tassels to prevent that last post meiotic mitosis. Roses have this occur in the pollen tube as it goes down to the egg, that is why I decided to apply the trifluralin to the stigmatic surface. As the pollen tube germinates and grows it will come into contact with the trifluralin and hopefully I wouldn’t interfere with any normal processes before that. This final post meiotic mitosis is just to take the generative nucleus and divide it into two copies- one to fertilize the egg and the other the central cell for endosperm.

By preventing that last division, there is only one nucleus to fertilize either the egg or pollen. Heterofertilization seems rare, but involves two pollen grains fertilizing the ovule. One can have a nucleus to fertilize the egg, another the central cell. This may allow for a generative nucleus disrupted in its final cell division to have twice as many chromosomes to fertilize lets say the egg and then some other pollen grain will hopefully fertilize the central cell with a normal or otherwise nucleus for successful endosperm formation and a viable seed.

I used one time blooming species because I wanted to have this marker to look for among the seedlings. If there was a repeat blooming seedling that would allow me to consider if the seedling is a haploid from an egg that developed into an embryo without fertilization and the nucleus from that grain didn’t divide normally and fertilized only the central cell for successful endosperm development.

In the end, I had very very very poor seed set using the trifluralin treatments, even at the lowest levels. Among the relatively few seedlings they were of the ploidy level expected.

Perhaps other concentrations or application methods (perhaps to the pollen itself) would yield better results.




Thanks Dave. Normally I check old threads when I come across articles as old as this one; but this time I did not.

I came across this article in a search for articles that added pollen in paraffin oil to maize. I was surprised to find that they apparently did not have to remove the paraffin oil from the pollen before using. Unfortunately all of the articles that I found referred to a M. G. Neuffer and E. H. Coe, Maydica, volumn 23, pages 21-28, (1978) article for the experimental details. I do not have computer access to that paper.

The following article does state that the oil/pollen mixture is added directly:

I am interested in this not because I plan on using EMS but because I am storing many pollens in oils and it would be nice if I could skip an acetone wash - filter step before using the pollen.