Monday, March 18, 2013

What about USDA 63-16-182?

  During the Annual Meeting of the KNGA there was a lot of discussion about a USDA clone known as 63-16-182 (photo at left). It seems that down in Georgia, a grower had found a tree of this clone and assumed he had discovered a superior chance seedling. The grower then applied for, and received a patent for this clone calling it "Eclipse". Genetic tests of trees grafted to 63-16-182 and to Eclipse revealed that the trees are genetically identical. Regardless of the name, we have had this clone under test at the pecan Experiment Field since the mid 90's.
    USDA 63-16-182 resulted from a cross of Mohawk and Starking Hardy Giant and is a full sibling of Pawnee. We grafted 63-16-182 into a block of trees that also included USDA 64-6-502, now known as Lakota. Lakota resulted from a cross of Mahan and Major. With these two scab-resistant cultivars established at the same time in the same location, its only logical to compare them. Lets first look at nut quality.

                    63-16-182                  Lakota
              -----------------------     -----------------------
              Nut wt.  % kernel     Nut wt.  % kernel
2010        6.51        60.02         8.81        58.22
2011        5.74        59.68         7.36        56.92
2012        6.31        58.35         7.68        58.67

    USDA 63-16-182 is a long, narrow nut that weights less, on average, than the wider, more-blocky Lakota cultivar (photo at right). The shape (long instead of blocky) and the extremely high % kernel of USDA 63-16-182 makes this clone very susceptible to shell breakage during mechanical harvest.  Kernel color of USDA 63-16-182 is not consistently straw-colored. Darker kernels often appear in cracked samples or kernels may display dark blotches (photo above).

     In terms of yield, a comparison with Lakota is also useful. During the early years of production (2001-2006), USDA 63-16-182 produced, on average, 245 lbs/acre. Lakota trees of the same age in the same block averaged 400 lbs/acre. In 2007, we loss the crop to the Easter Freeze. Later in the December 2007, we suffered an ice storm that severely damaged our orchard. USDA 63-16-182 was among the hardest hit cultivars by ice with over 75% limb loss (photo at right). In contrast, Lakota trees lost between 31% and 50% of their canopy limbs. Since the ice storm, the yield  of these trees reflect the differences between USDA 63-16-182 and Lakota in terms of the severity of canopy loss, rate of yield recovery since the ice storm, and overall productivity.

                Yield (lbs/acre)
           63-16-182    Lakota
2008          0               246
2009          0               710
2010         87             1081
2011        271            1428
2012        881            1694

USDA 63-16-182 ripens about 6 days before Pawnee at our location. That's about the same time as Peruque and 3 weeks earlier than Lakota. The early ripening characteristic of USDA 63-16-182 makes this clone adaptable to many northern pecan growing areas but that advantage is overshadowed by numerous deficiencies we've observed in kernel quality, tree productivity, harvest-ability, and tolerance to extreme weather conditions.  Simply stated, USDA 63-16-182 is a clone I would not include in my orchard.