Wednesday, May 18, 2022

Notes on pecan pollination

     Last weekend I took advantage of calm winds and sunny skies to photograph pecan flowering and pollination. I also like to scout my orchard at this time of year to get a feel for this year's nut crop. During the month of May, my trees are always covered with catkins--the long worm-like structures that hang down from last year's shoot growth. Male flowers (pollen sacs) cover each catkin and eventually split open to release millions of yellow pollen grains into the air to hopefully find their way to a receptive female bloom.

    Pecan female blooms are not very showy (photo at right) and can be found at the terminal new spring shoot growth. Look carefully at the flower cluster in the photo and you will note that the ends of each flower (the stigmatal surface) has started to turn dark brown-black indicating these flowers have been pollinated. The flower cluster pictured here is from a Kanza tree. Kanza is a protogynous cultivar meaning the female flowers on the tree become receptive early in the pollination season while Kanza pollen is released late.

     When scouting my orchard for yield potential, I concentrate on counting the number of terminals on a tree that have developed female flower clusters. The good news for my orchard is that the 2022 crop looks very promising at this point.

On my trip around the orchard, I decided to concentrate recording the flowering habits of the pecan cultivars originating from my breeding project. I took 2 photos of each cultivar. The first shows the entire fruiting shoot. The second is a close-up of a female flower cluster. All photos were taken on May 14th. I've noted the flowering habit of each cultivar.


Caney was actively shedding pollen at the time this photo was taken.

Caney pistillate flowers were still growing and not yet receptive. The stigmas will be bright red at receptivity.









Earlton has long slender catkins typical of protogynous cultivars.

A Earlton flower cluster shows signs of already being pollinated.


Look carefully. See if you can spot the female flower cluster held at the end of the new Labette shoot.

Labette female flowers look ready to receive pollen.


Liberty was shedding pollen and should make a good pollinator for Kanza.

Liberty female flowers were still growing in size. Stigmas will be red in color.


Pleasanton catkins are starting to turn yellow in color. It won't be long before pollen sacs start to open and release their pollen grains.

Pleasanton female flowers have started to turn brown indicating pollination has occurred.


St. Paul catkins were shedding pollen. So much pollen that I had to clean off my camera lens.

St. Paul female flowers were still not fully formed. These females will have green stigmas.


Thayer catkins have shed most of their pollen and have turned brown in color.

Thayer female flowers are still growing. The stigmas will be bright red when receptive to pollen