Sunday, October 13, 2013

Pecan diversity

Nuts from seedling pecan trees compared to Pawnee (circled)

    Most pecan growers understand genetic variation in pecan simply because they have grafted a dozen or so cultivars into their orchards. We have large pecans and smaller pecans. There are cultivars that bear heavily and those that are shy producers. Some cultivars seem to have a crop every year while other trend towards alternate bearing. Everyone has grafted cultivars they wish they hadn't, and sometimes we wish we had grafted more of a particularly outstanding nut.
    The genetic diversity within pecan is amazingly wide. In our breeding plot, we used Pawnee as one of the primary parents in making controlled crosses. In the photo above, I've arranged some of the seedling nuts we have collected that ripen before or at the same time as Pawnee. The two nuts circled in the center of the photo are Pawnee nuts to give you a reference for comparison.
    There are a couple of seedling nuts that remind of the Pawnee parent, but the vast majority are drastically different in size and shape. Some of these seedlings will have thick shells while others will be thin shelled. But remember, nut size and percent kernel are just two traits that we need to look at in searching for new pecan cultivars. Disease resistance, good tree structure, and high yield are three major traits are also on the top of my wish list. Its no wonder that new, exceptional, pecan cultivars are so hard to come by.