During the first half of September we received several, much-needed rain showers. The additional moisture has had a big impact on pecan kernel fill, helping to fully pack the inside of the shell with kernel. Last week I collected nut samples from four pecan cultivars and then this week, I collected nuts from the same cultivars. I cut open the nuts in cross-section and then photographed kernels. By comparing the photos taken a week apart you can see how pecans fill their kernels late in the season.
The photo above shows two cultivars. Pawnee nuts are shown on the left and Kanza on the right. The nuts collected last week are shown above the nuts collected this week.
Now let me point out some key differences between last week's and this week's pecans. First, note that the Pawnee shuck has separated from the shell. Pawnee should be in full shuck split by the end of this week. Now focus on the packing material between the kernel halves and the material that fills the dorsal groves of the kernel. On September 14 this packing material was orange in color and still spongy in character. By September 21, the kernels of both Pawnee and Kanza had expanded significantly and compressed the in-shell packing material. The partition between the kernel halves became thinner, changed color, and became harder. The packing material in the dorsal grooves also became compressed and turned brown in color.
I also collected nuts samples from Lakota and Giles. These two cultivars ripen in mid-October so they are still working on filling their kernels. However, over the past week both cultivars have developed much plumper kernels and compressed internal packing material. Over the years, we have noticed that Giles often struggles to develop full, meaty kernels. Based on the number of air pockets still present in Giles kernels at this time, the 2016 Giles crop will be no different.
