Florida Growers Wanted for Rootstock Trials

Ernie NeffResearch, Rootstocks


The Citrus Research and Development Foundation (CRDF) is establishing a new project to evaluate the most promising citrus rootstocks in grower field trials. The rootstock trials are projected to be planted in the spring or summer of 2022. The goal will be to identify plant material with the traits needed for growers to realize the highest possible pound solids per acre and increased tree viability in the HLB era. 

These will be large-scale field trials assessing new rootstock varieties in the final phase of evaluation. Trials will be scientifically designed and set up for data analysis to identify the best-performing varieties. Sixteen rootstocks have been chosen for evaluation based on superior performance in small-plot field trials. 

Some of these rootstcks will be plant material not previously available for commercial use, and others will be known rootstocks which will be used as a standard for comparison. Rootstocks to be tested are:

  • U.S. Department of Agriculture candidate rootstocks 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 UFR-5, Orange 14 and Blue 1
  • Testable rootstocks US-812 and C54
  • Standard rootstocks X-639, US-942, Kuharski and Swingle (sour on the East Coast)

Three scions will be used: Valencia 1-14-19, Vernia UF 35-15 and Hamlin 1-4-1. These scions will be combined with the 16 rootstocks, 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 amount of trees for each trial site is 4,800. At a planting density of 200 trees per acre, each site will require about 24 acres.


CRDF will require three trial sites for this project. The goal is to identify grower cooperators willing to host a trial in each of the three eco-regions of the Florida citrus industry: Ridge, East Coast and Flatwoods.

Growers selected to host a trial will be provided trees at no cost and a supplement for tree planting and installation of tree wraps. CRDF personnel and subcontractors will require regular access to the field trial planting to conduct evaluations, plant tissue and soil sampling, tree canopy rating, and per-plot yield evaluation once the trees reach bearing age. CRDF will plan and conduct an annual field day at a selected site to disseminate data. The data will be shared on the CRDF website.

Grower cooperators will be expected to uniformly apply production inputs to support the trees from establishment to mature tree production. Production practices are expected to conform with UF/IFAS recommendations for irrigation, drainage, fertilization and pest control. No special treatments will be allowed in the trial as they could possibly invalidate the rootstock trial data.

Growers interested in participating and hosting a trial site should submit a letter via email to catp@citrusrdf.org with contact information, site location, soil type and acreage available.

Source: Citrus Research and Development Foundation

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