We were shaking some Kanza trees today, when I noticed a few bright green shucks still up in the tree. Most often its just one nut in a cluster of 3 to 4 nuts (photo at right). If you look closely at the still-green nut, you'll note that the shuck hasn't even split open. The fact is, this nut will never split open and will become what we call a stick-tight.
I pulled some nuts off of our pecan cleaner's inspection table to find out what going on inside the nuts that remain stick-tights. In the photo at left, two stick-tights are shown next to two normal Kanza nuts. I cut each of the nuts in half to reveal what is inside the shell. The normal pecans had nicely filled kernels while the stick-tights had kernels that never fully formed.
It is the maturing seed inside the shell that triggers normal shuck opening. Without a fulled developed kernel inside, the shuck will never open.
What causes kernels not to fill out? In this case it is not clear. Stinkbug feeding can cause a similar lack of kernel development but the interior portion on the nut would be jet black in color. Disease is not the cause because the nut appears perfectly healthy. This lack of kernel fill is most likely due to a miscue in tree physiology. For some reason the kernel filling process was switched off during the water stage of kernel development.
The appearance of these kind of stick-tights at harvest is not exclusive to the Kanza cultivar. When we cleaned our Pawnee pecans, I found stick-tights with a similar lack of kernel development (photo at right). Thankfully, the number of stick-tights we harvest is only a small fraction of the total number of nuts we collect each Fall. It just drives me crazy to pull stick-tights off the cleaning table and think--what did I do wrong? The answer is probably, nothing. I guess our pecan trees are just not perfect when it comes to filling out every kernel on the tree.
