Friday, August 19, 2016

Nut Development: Shellbark hickory vs. Pecan

  Over the past several weeks, I've been recording the development of several pecan cultivars. Hopefully, you have been able to see differences in the rate of kernel development between early ripening cultivars and later ripening cultivars.
    Today, I want to highlight the differences in nut development between two distant cousins in the hickory family--Shellbark hickory and pecan. The shellbark hickory produces a huge fruit that appears to be at least 3 times larger than a pecan fruit (photo above right). To check on the development of the nuts inside these fruits, I cut each fruit in half.

     The pecan shell had only just started to harden up and I could slice through the entire fruit with a pocket knife. In contrast, I had to use a band-saw to open up the hickory. In the photo at left, the huge difference in stage of kernel development between species is very clear. The shellbark hickory is fully packed with kernel while the pecan is still in the water stage.
    The cross section of the hickory nut also reveals some major negative characteristics associated with shellbark hickory as compared to pecan. The hickory has both a very thick shuck and shell. At harvest the shuck of the hickory remains woody, clings to the nut inside,  and is difficult to remove from the nut. Pecan nuts fall from the shucks after a good hard freeze. The thick shell of the hickory and the bony partition between kernel halves make extracting nut meat difficult. In contrast, the Kanza pecan shells easily producing a high percentage of kernel halves.