Revisiting the ‘Parson Brown’ Sweet Orange

Abstract

In 1923, J.L. Carney described the origin of the ‘Parson Brown’ sweet orange (Citrus sinensis). Historically this was a common cultivar, especially in north central Florida. Many of the ‘Parson Brown’ plantings were lost in the series of freezes from 1962 through the late 1980s and replaced with other cultivars for various reasons. Since the onset of citrus greening (HLB), there have been reports of surviving ‘Parson Brown’ trees not being as affected as some other cultivars. Observations made on some trees reputed to be over 100 years old in the original area where ‘Parson Brown’ was cultivated revealed little apparent affect from HLB. Initial qPCR testing on a set of these trees in 2014 indicated no HLB detected, although some visible symptoms often associated with HLB infection were observed. Additional PCR testing on the original trees plus some others was initiated in 2015. Budwood from the original trees was collected and propagated to challenge with HLB infected Asian citrus psyllid Diaphorina citri.