July is the month when northern pecans enter a period of rapid fruit enlargement. Even though pecans are a nut crop, we call it fruit enlargement because the shuck and seed within are collectively termed a pecan fruit. Botanically, pecans are similar to peaches. The hard-shelled seed of a peach tree is surrounded by a fleshy outer-layer that we just love to eat. However, we discard the peach pit or seed. With pecans, we disregard the fleshy outer-layer and eat the seed within.
On Thursday, July 21, I collected a few pecan fruit from several cultivars to check on the status of fruit enlargement. The first group were pecans from early ripening cultivars (photo above right). Cutting open these nuts I found that these nuts ranged in kernel development from 1/4 water stage (Colby) to nearly full water stage (Warren 346).
The next group of cultivars had pecans that were all very similar in size at this point in the growing season (photo at left). However, these cultivars represent a wide range of ripening dates. At harvest, Peruque will be the smallest nut while Maramec will be nearly twice the size of Peruque.
After cutting open each nut, I could see differences in kernel development (photo at left). Peruque was at 1/2 water stage while the Maramec kernel was still at the small heart stage. The Faith and Waccamaw nuts were approaching 1/4 water stage.
The final group of nuts I collected were from four scab free cultivars (photo at right). The Kanza and Hark nuts looked plump and well on the way to full fruit sizing. Lakota looked narrow and not as far along. Oswego, a nut that at harvest will be similar in size to Kanza or Hark looked significantly smaller.
Cutting open each nut I found Kanza and Hark to be at 1/4 water stage. The Lakota had slightly less kernel development. But Oswego kernel development was far behind, still at the small heart stage.