Friday, August 12, 2011

Checking nut development

    Pecan growers are often curious to see how their nut crop is progressing. Cutting nuts open at this time of year  is a good way to check on kernel development. The photo at left shows a native pecan that has almost made it to full water stage (you can even see the drips of liquid endosperm.spilled near the nut halves). If the nut is cut just right (like the one in the photo), you can see both halves of the expanding kernel. If you cut the nut open the wrong way, all you'll see is the area of the kernel that connects the two halves. So here is a brief lesson on cutting open pecans to check nut development.

    When you pull a nut off the tree, look at the stem end of the nut. Notice that the attachment scar is oval in shape (photo at right). The long axis of the oval is in line with the partition that separates the two kernel halves. The short axis of the oval cuts across the kernel halves.

    To see kernel development, you need to cut the nut along the short axis of the oval. In other words, cut on the red line shown in the photo at right. Note that on many pecan cultivars, there is a scruffy tan line on the outside of the shuck that marks the location you need to cut.

     To cut the nut open, I use a pruning shear. With the blade wide open, I push the nut into the blade right along the cut line (photo left). The stem end of the nut is located at the top of the photo, in a position I can see that the nut is properly oriented in the shear. I then cut the nut in two. Make sure you hold the clippers and nut away from your body, the water inside the nut will stain your hands and clothes black.

   Once the nut is cut in two, you should be able to see both sides of the kernel. The yellow arrow in the photo at right points to the kernel. At this point the kernel appears empty but it was filled with liquid endosperm before the nut was cut open.