Saturday, July 31, 2021

Checking pecan kernel development

     Its that time of year when I really start to notice the pecan crop hanging on my trees. The photo at right shows a cluster of Kanza nuts as they appeared 30 July 2021. At this point in the growing season, pecan nuts are in the phase of rapid fruit expansion  meaning that the nuts you see in the photo will almost double in size over the next 2 weeks.

   To check on the development of the kernel inside the nut, I took samples from several pecan cultivars and cut them open (photo at left). The kernels were less than one half expanded and still filled with liquid endosperm. Compared to previous growing seasons, this year's pecan crop is well behind schedule. An early maturing cultivar, such as Gardner, is usually at full water stage by the first week of August.  Since nut development is delayed this year, I expect pecan ripening (date of shuck-split) to be later than normal.

   If you remember back to earlier this Spring, we had a much cooler than average month of May. This lack of heat delayed the pollination season and slowed the embryo fertilization process. The net result has been that the normal biological clock for kernel development got a very late start.

   From a practical viewpoint, the delay in kernel development will impact the proper timing for crop load management and sprays for pecan weevil.