Tuesday, June 2, 2015

Pecans don't grow true from seed

    Over 30 years ago, we planted Giles seedlings in our pecan grove to help fill in the gaps that existed among much larger native pecan trees.  Since that time, the trees have grown and matured into nut bearing trees. In the photo above, I have outlined a pair of Giles nuts. The rest of the nuts in the photo were harvested from the Giles seedlings. Note that not one of the nuts produced by the seedlings looked exactly like a Giles nut.
    The Giles seed we used for these trees dates back to the 1980's and originated from our field trials at that time. Since pecan is a wind pollinated crop, the pollen parent for these seedling trees could have been anything from a native tree to a large improved cultivar such as Mohawk or Maramec. Its obvious from the photo above that some of the seedling trees received  some "large nut" genes from the pollen parent.

     The table at left provides some additional data on these Giles seedlings. For the 2014 crop year, our Giles nuts averaged 6.36 g/nut and 52.66% kernel. All but one of the seedlings produced nuts that were smaller than the parent tree. Only four seedling trees produced nuts that had higher percent kernel than the Giles parent.
    Of all of the seedling trees, KS800 has consistently produced nuts with outstanding kernel quality and appearance. However, this tree has 2 negative traits. It has an upright growth form that produces numerous narrow angled branch connections. But more importantly, the tree is a light nut producer.

     The moral of this story is that it is very difficult to find outstanding new pecan cultivars by just growing out some open-pollinated seed. We planted these trees in our native grove knowing full well that we wouldn't discover a new "super Giles" tree. We did, however, establish some new trees in our native grove that preserved the genetic diversity of our tree stand while improving the average percent kernel of our native crop (natives average 45% kernel, the Giles seedlings averaged 50.64% kernel).