Thursday, May 5, 2016

Pecan pollination season rapidly approaches

   Yesterday, I took a quick trip around the Pecan Experiment Field to check for pistillate flowers (female flowers) on our pecan trees. The catkins or the male flowers have been out for some time but the female flowers are just now starting to show themselves at the ends of new shoots on protogynous cultivars. Lets take a look at the 2016 pecan pollination season as of 4 May 2016.

Pawnee catkins
   The first thing I noticed was that early pollen shedding cultivars (protandrous), like Pawnee, had large fully developed pollen sacs (photo at right). The pollen sacs will eventually turn yellow just before they split open and release millions of pollen grains into the air.

Kanza catkins

    In contrast, late pollen shedding cultivars (protogynous) have long narrow catkins with pollen sacs that are still far from obtaining full size (photo at left). It will be a couple of weeks before pollen is released from these Kanza catkins.

City Park pistillate flower cluster
   The only pistillate flowers I could find yesterday appeared on protogynous cultivars. In looking at several cultivars, I found flower clusters in several stages of development. Pistillate flowers on some cultivars were just beginning to peak out of a terminal's new growth (City Park, photo at right), while others had fully formed flower clusters (Mullahy, photo below). I was very glad to see a good pistillate flower crop developing on my Kanza trees (photo below).

Mullahy pistillate flower cluster

Kanza pistillate flower cluster