Freeze Tolerance Is Key to Diversification

Freeze tolerance is a focal point of citrus studies conducted at the University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) North Florida Research and Education Center in Quincy.

As citrus production continues to grow in the cold-hardy citrus region, growers need varieties that are able to withstand prolonged periods of sub-freezing temperatures. Leading that research is Muhammad Shahid, UF/IFAS assistant professor of horticulture. He discussed the need for freeze-tolerant varieties and his research on the fruit during the Cold-Hardy Citrus Field Day and Workshop in Quincy on Oct. 1.

“We are working to enhance the freeze tolerance of citrus. In my program, we are working on two parts. The applied part includes the basic structures, techniques and cultural practices where we can enhance freeze tolerance,” Shahid said. “The other part we are working on is the fundamental approaches. What are the mechanisms of freeze tolerance? It’s information that we can pass on to the breeders, and they can develop the freeze-tolerant varieties.”

Freezing temperatures are not uncommon in the cold-hardy region. The December 2022 freeze led to trees being thrown into an extreme alternate bearing cycle, leading to very low production in 2023. Historic snowfall this past January also impacted trees.

Satsuma mandarins have long been the predominant variety grown in North Florida, South Georgia and South Alabama. Resistance to freezing temperatures make satsumas ideal to grow in the region. But as evidenced by last year’s oversupply of the fruit, growers need viable alternatives to produce alongside satsumas. That’s another driving factor in Shahid’s research.

“Most of the industry — 90% — is saturated with satsuma mandarins. There’s a need for diversification. We need to introduce a variety that can give us early harvesting, like in August and September, so we can avoid the freeze events,” Shahid said. “With diversification, we will enhance the profitability of the growers. Instead of a two-week harvest window, you’ll get four months of harvest with different varieties. It’s good for the sustainability of the industry.”