Monday, July 6, 2015

Using Unknown Pollen

While on a recent trip I came across a most beautiful and floriferous rose.  It was labeled as the species rose, Rosa arvensis.  A fellow rose breeder from France, Pascal Heitzler, who had used Rosa arvensis extensively, was able to definitively say that the rose was mislabeled, and was definitely not R. arvensis.  Unfortunately, he was not able to identify this amazing rose. 

As seen below, it is a small flowered rose, blooming in very large clusters on a vigorous plant.  The flower buds are light yellow, though the blooms fade to nearly white a few hours after opening.  The foliage is medium green, semi-glossy and appears to be very clean since I did not see any disease on this specimen although there were many other roses in the garden infected with powdery mildew, black spot, and some even had downy mildew on them.

So, being the rose breeder that I am, I needed to see if this rose could be crossed with some of my own seedlings.  I wondered whether the rose was fertile and whether I could manage to get some of it's pollen home with me.

I collected 10 unopened flower buds, in various stages of development (1-2 days from opening).  These were gently wrapped in a moistened paper towel and placed in a zip-lock bag.  Upon arriving home, the zip-lock bag was put in the refrigerator and 2-3 buds were removed each day to gather pollen for drying.  Over the course of the next 4 days I was able to make over 100 crosses onto some of my better seed parents.  Below is the pollen cup that was used (the pollen was labeled with "R. arv" even though it is not the correct name). The three buds in the photos below were the last of the 10 that had been collected.

Five or 6 days after the buds were collected, there was still some apparently viable pollen on the last 3 buds as seen below.

The last photo was taken to demonstrate how small the flower buds were.

Now, one month later, it appears that the pollen was fertile since hips are beginning to form on the selected seed parents.  Although I hope that someone will one day be able to identify this rose, more importantly, I am hopeful that I will have some seedlings from it sprouting in my greenhouse next year.  I wonder whether this rose is remontant, or if it is a once-blooming rose, will I have to wait 2 or 3 years to see the first blooms on it's seedlings?  That is a question that will be answered next year.