University of Florida scientists have developed a mandarin hybrid that seems to be winning the battle against citrus greening disease.

UF/IFAS researchers have discovered that a mandarin hybrid developed by colleagues contains cellular activity known as metabolites that makes it more able to fend off greening than most other types of citrus.

Nabil Killiny, an assistant professor of plant pathology said, from field observation, scientists with UF/IFAS found the ‘Sugar Belle’ mandarin is less affected by citrus greening than other mandarins. Researchers want to know what makes the ‘Sugar Belle’ resistant.

Killiny’s study focused on identifying the chemicals found in ‘Sugar Belle’ trees that have been shown to fight against diseases in other plants.

Scientists at the UF/IFAS Citrus Research and Education Center in Lake Alfred, Florida found ‘Sugar Belle’ mandarin is high in several volatiles and beneficial compounds – known as phenolics. These findings could tell scientists why ‘Sugar Belle’ mandarin is more tolerant to Huanglongbing, or HLB, also known as citrus greening.

Researchers tested volatile and non-volatile metabolites of the greenhouse-grown mandarin trees. Among other traits, volatile metabolites emit odors, while non-volatile metabolites do not.

To analyze the metabolites, they used gas chromatography – mass spectrometry and found the ‘Sugar Belle’ mandarins to be relatively tolerant. Other newly released mandarins should be further evaluated using greenhouse-controlled studies, the paper says. If tolerance of these hybrids is confirmed, they could be used to replace the traditionally susceptible cultivars.