Manjul Dutt recently discussed his research on the Parson Brown (PB) sweet orange, which shows some characteristics that could make it more attractive than Hamlin, Florida’s leading early-season orange. Dutt is a University of Florida Institute of Food and Agricultural Sciences horticultural sciences researcher at the Citrus Research and Education Center in Lake Alfred.
Dutt’s research, funded by the Citrus Research and Development Foundation (CRDF), aims to understand whether Parson Brown’s HLB tolerance is rootstock independent. The research also aims to identify select PB clones with improved horticultural qualities.
Parson Brown was identified in 1875. By the mid-1920s it had become a popular early-season orange in Florida. It eventually fell out of favor due to its seediness, peel oil content, poor fruit quality and because it had lower yield than Hamlin.
In Dutt’s research, PBs are being studied in eight blocks in Polk, Highlands, St. Lucie, Glades and Collier counties. Dutt’s project was initiated in January 2021, in part to learn the role of systemic-acquired resistance to HLB in Parson Brown.
The PBs Dutt is studying were as HLB infected as Hamlins but are doing much better than the Hamlins, he reported.
All PB trees, irrespective of their location, have much lower fruit drop compared to Hamlin, Dutt said. Blotchy mottle on leaves of PB trees was less pronounced than those on Hamlin, and PB trees had better canopy density with much lower dieback than Hamlin, he added.
As part of the research, PB and Hamlin leaf samples are being collected four times per year for HLB evaluation. Fruit weight, percent juice, pounds solids, percent acid, total Brix, Brix/acid ratio and juice color will be measured.
Dutt was one of several presenters in a July virtual educational session hosted by CRDF and Florida Citrus Mutual.
Learn more about Parson Brown observations that led to Dutt’s research.
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