Progress Toward HLB-Tolerant Citrus

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Sugar Belle

Largely due to the advent of huanglongbing (HLB) disease, Florida orange production has declined by over 70 percent in the last 10 years. According to experts, if the trend is not reversed, processing plants will not have enough fruit to maintain production and profitability, ultimately causing shutdowns.

Currently, Florida law requires that orange juice be comprised of at least 90 percent sweet orange juice. Given the poor growth, cropping and reduced fruit quality common in sweet oranges infected with HLB, the Florida orange juice industry is being asked to reconsider this restriction.

Anne Plotto, a research plant physiologist for the U.S. Department of Agriculture Agricultural Research Service, discussed a project funded by the National Institute of Food and Agriculture during the recent virtual citrus Packinghouse Day meeting. The project focuses on exploring HLB-tolerant hybrids as new commercial cultivars for fresh and processed citrus.

The study aims to identify HLB-resistant/tolerant hybrids that have the same great flavor profile consumers expect to find in their juice and that can be quickly mobilized for use by the U.S. citrus industry.

According to Plotto, a lot of progress has been made in the course of this project. From 2016 to 2019, 48 different hybrids and named cultivars were evaluated. Researchers tested their sensitivity to HLB and their flavor profile.

“Off the bat, we eliminated very bitter hybrids,” Plotto said. To maintain the quality of fresh Florida orange juice that consumers have come to know and love, the researchers put their efforts into the hybrids that most resembled the flavor profile of sweet orange juice.

Several of the cultivars appear to have commercially useful levels of HLB tolerance. The two most noteworthy cultivars are Sugar Belle and SunDragon. Of the different sweet orange-like hybrids that have been evaluated, FF-5-51-2, FF-1-85-109 and FF-1-85-124 seem to be the most promising and have good orange flavor.

See Plotto’s Packinghouse Day presentation here.

Ashley Robinson, AgNet Media communications intern, wrote this article.