Characterizing HLB-pH interaction to improve management of root function and tree health

Characterizing HLB-pH interaction to improve management of root function and tree health

Report Date: 08/18/2020
Project: 18-041C   Year: 2020
Category: Horticultural & Management
Author: Evan Johnson
Sponsor: Citrus Research and Development Foundation

The objectives of this study are to identify optimal pH range for root function and minimize root turnover on HLB-affected rootstocks and how uneven pH levels in the root zone (e.g. irrigated vs. row middle portions of root system) affect the overall health of the tree.  This is being done in a split root system in the greenhouse where pH of different parts of the root system can be controlled an maintained. The following progress reported is based on a July 31st report date.  The breakdown of the first experiment has been completed and preparation for setup of the 2nd experiment is underway.  Initial findings from the first experiment will be presented virtually as a poster at the American Phytopathological Society annual meeting the 2nd week of August.   Final dry mass, gene expression, and CLas population data is still being collected on samples from the first breakdown.  Initial observations from breakdown suggest that roots suffer minimal damage at some soil pH environments pH 7.5 for US942 and pH 5.5 for Swingle.  Swingle roots were most damaged by HLB at pH 7.5 and US942 roots were most damaged at pH 5.5.  More information will be provided when the quantitative data has been analyzed from the first experiment.        


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