The University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) hosted a field day in Jason Griffin’s Polk County grove in mid-September. Griffin has been a long-time collaborator with the citrus breeding program. The event featured many of the later-season OLL varieties developed by Jude Grosser, UF/IFAS professor of plant cell genetics.
The OLL line of later-maturing varieties stems from the work of the late Ori Lee, who identified a tree in his grove with some promising attributes almost 20 years ago. Those genetics have been replicated and improved over the years.
Grosser said the goal of the UF/IFAS breeding team was to leave the citrus industry with trees that can be grown in the more traditional way without the current countermeasures to HLB. This would help the industry get back to a more profitable scenario.
“My philosophy is based on a three-legged stool, which I think is what it will take to make it all work,” Grosser said. “The first is rootstock genetics; we’ve been working really hard to select rootstocks that mitigate HLB regardless of the scion you graft on them.
“The second leg is improved scion genetics. We have recently found some new clones of OLL and a new clone of Valencia that are stronger than anything we’ve had so far. Those are listed in our new variety guide.
“The third leg of the stool is what we are learning about nutrition. This disease (HLB) causes severe deficiencies in all the micronutrients and we are growing trees on sand. So, growers need to find a way to elevate all those nutrients. It is not really a nitrogen, phosphorus and potassium problem, it is all those secondary micronutrients.”
Highlighting the improving productivity of the grove, Griffin noted that it broke even economically this past season. He attributed that in part to some of the newer, more productive rootstocks and scions planted in the grove.
While Sugar Belle has had its challenges in some areas as a fruit tree, Grosser noted that as a hybrid parent for rootstock development, there are some promising selections being identified in his research.
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