Monday, August 28, 2017

Pecan cultivars: Checking on kernel development

    I collected nuts from 24 pecan cultivars and cut open nuts to check on kernel development. The four cultivars shown above are some of our early ripening pecans. All four have developed kernel tissue but they still have a ways to go until the nut becomes fully packed with kernel. The Peruque nut was heavily infected by pecan scab which translated into a smaller nut and poor kernel filling.

     The four cultivars pictured above represent some of our earliest ripening cultivars. Warren 346 and Lucas look pretty well packed with kernel but judging from the width of the inner-wall partition these two cultivars are still developing more kernel. Mullahy and Goosepond are only slightly behind Warren 346 and Lucas in terms of kernel fill.

    The four cultivars in the photo above illustrates the wide differences I observed in kernel development during late August. Pawnee and Faith have laid down a thin layer of kernel with Pawnee being further advanced than Faith. The Mandan nut has a developed a thin layer of translucent kernel (under-developed cells) while Mohawk is still in the water stage.

    These next four cultivars are all in the early stages of kernel deposition (photo above). Posey and Surecrop are ahead of Greenriver and Oswego. It is interesting to note that both Posey and Surecrop have prominent wings on the sutures of the shuck. Surecrop originated as a seedling in Carlinville, IL. Could it be that Surecrop is a seedling of Posey. Large suture wings are fairly rare among pecan cultivars.

    Although SWB617 is a Giles seedling, this cultivar is far ahead of its parent in terms of kernel development (photo above). On the other hand, Jayhawk, another Giles seedling, lags behind its parent. Chetopa is in the earliest stages of kernel development.

    This last group of four cultivars include Major and three of her progeny; Kanza, Lakota, and Hark (photo above).  Kernel development of Major and Kanza is roughly the same, while Hark appears slightly advanced. Lakota was still in the water stage and showed no signs of kernel development at this point in the growing season.