CRDF Seeks Growers for Rootstock Trials

Josh McGill CRDF, Rootstocks

The Citrus Research and Development Foundation (CRDF) is seeking Florida citrus growers on the Ridge and in the flatwoods of Southwest Florida to potentially be grower-cooperators in large rootstock trials. The goal of the new trials is to identify plant material with the traits needed by growers to realize the highest possible pound solids per acre and increase tree viability in the HLB era.

Rootstock Trials

CRDF intends to have three approximately 24-acre trial sites for this project, including the ones on the Ridge and in Southwest Florida. A trial site on Florida’s east coast has already been determined.

The rootstock trials will utilize 16 rootstocks chosen for evaluation based on superior performance in small-plot field trials and/or observational data. U.S. Department of Agriculture candidate rootstocks are US-1282, US-1283, US-1281, US-1279, US-1284, US-1516 and Super Sour 2. University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) candidate rootstocks are UFR-5, Orange 14 and Blue 1. Also being evaluated are testable rootstocks US-812 and C-54, and standard rootstocks X-639, US-942, Kuharski and Swingle.

The 16 rootstocks will be combined with three scions: Valencia 1-14-19, Vernia UF 35-15 and Hamlin 1-4-1, resulting in 48 rootstock/scion combinations. Each rootstock/scion combination will be replicated five times for a total of 240 plots in the trial. Each plot will have 20 trees per rootstock/scion combination. The total number of trees for each trial site is 4,800. At roughly 200 trees per acre, each site will require approximately 24 acres.

Growers selected to host a trial would be provided trees at no cost plus a supplement for tree planting, tree wraps and first-year establishment costs. Excluding the value of the tree, these financial supplements amount to $8.95 per tree for Vernia and Valencia trees and $13.95 per Hamlin tree.

CRDF personnel and subcontractors will require regular access to the trials to conduct evaluations, plant tissue and soil sampling, tree canopy rating, and yield evaluation once the trees reach bearing age. In addition, CRDF will plan and conduct an annual field day at each site to disseminate data, which will be shared on the CRDF website.

Grower-cooperators would be expected to uniformly apply production inputs to support the trees from establishment through to production. Production practices are expected to conform with UF/IFAS recommendations for irrigation, drainage, fertilization and pest control. No special treatments would be allowed in the trial.

Growers interested in participating and hosting a trial site should submit a letter by email to with their contact information, site location, soil type and acreage available. Letters of interest from growers must be received by CRDF no later than 5 p.m. on May 16, 2022.

Source: Citrus Research and Development Foundation

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