By Clint Thompson
Quality issues remain a concern for Georgia and Alabama farmers who are on the cusp of harvesting this year’s crop.
Lenny Wells, University of Georgia Extension pecan specialist, talked about nut issues like sprouting and embryo rot during the Georgia Pecan Growers Association field day on Sept. 3.
Pecan quality is vulnerable if weather conditions turn off dry in late September and October. The trees in some areas have received plenty of rainfall this summer. But if the rains suddenly stop, it could be a shock to the tree’s physiological system.
“I think for our Pawnees, we’re already seeing shucks split on them. We’ve had a few rains recently, and they look okay as far as that goes,” Wells said. “But for our major varieties that are harvested a month later, we’ve still got some time to go to determine whether that’s going to be a problem or not.”
Premature Germination
Sprouting can refer to premature germination of the nut.
“That nut, which is the seed, just basically germinates and sprouts. Sometimes it will begin to sprout, and then the little sprout of that embryo that’s trying to grow will die,” Wells said. “That’s where you get embryo rot. If it continues to develop and you see the sprout itself, that little root that’s growing comes out, it survived longer and could can send that root out like that. But it’s all part of the same problem.
“That comes from stress, and that stress generally comes in the form of having a pretty good crop load on the trees, and then we also get hot and dry after kernel filling.”
Wells noted in the UGA Pecan Blog that, “hot and dry conditions can cause under-irrigated trees to stress, especially under a heavy crop load, until the shuck split process has been completed. The stress causes the nuts to be stimulated by conditions that mimic those needed for germination as moisture is conserved inside the shuck,” Wells said. “This combined with the high temperatures can lead to premature germination.”
“Basically, when the tree gets stressed and it can’t get enough water to open those shucks and those shucks stay closed, the conditions inside that nut, especially if we’re hot and dry, the trees concentrating moisture around that nut to protect it,” Wells said. “The shucks stayed really hydrated and the tree, the soil itself is dry, air is dry, it’s hot. And what happens then, you’ve got perfect conditions inside that nut for germination to take place.”