Comparison of field performance of citrus trees on rootstocks propagated by seedlings, cuttings, and tissue culture

Comparison of field performance of citrus trees on rootstocks propagated by seedlings, cuttings, and tissue culture

Report Date: 04/01/2019
Project: 18-028C   Year: 2019
Category: Other
Author: Ute Albrecht
Sponsor: Citrus Research and Development Foundation

Good progress was made to accomplish the objectives for this project during the first quarter in year 1 of this project. One field trial was established at the UF/IFAS SWFREC farm in November 2017. Two commercial trials were established in Collier County and in Polk County in April of last year. Prior to planting, a subset of trees was destructively sampled to assess root system architectures and other plant growth parameters in detail. Data from these measurements are being prepared for publication. Since trial establishment, trees have been closely monitored and horticultural measurements were conducted as outlined in the project proposal. Horticultural measurements include tree height, canopy size, scion and rootstock trunk circumferences, and canopy health. Tree wraps were regularly inspected for ant problems or other issues that may negatively impact tree growth and health. Bases of rootstocks were assessed for potential abnormalities arising from propagation. Root growth has been monitored monthly in the SWFREC trial since trees were planted. Root measurements are non-destructive, making use of rhizotrons (long plastic tubes) and an associated camera and software system. Root measurements were continued during the first quarter of the funding period. Additional rhizotrons were purchased and prepared for installation to the root zone in a subset of trees from the two commercial locations. Rhizotron preparation included post-purchase modifications such as applying paint and sealing openings for blocking out light and moisture. The first set of rhizotrons was installed during the third week of March at the Polk County location (Peace River Packing Co). The second set was installed during the last week of March at the Collier County location (Duda & Sons). In each trial, 102 rhizotrons were installed. Root growth measurements will commence in April once the soil has settled and roots have recovered from any stress that may have been induced during installation. One person (OPS) was hired and began work in the last week of March. Propagation of new plant material in the DPI-approved USHRL greenhouses commenced. Four rootstock cultivars were used. Rootstock liners were generated from seed, from tissue culture, and from cuttings, and were grafted with `Valencia’ scion. Trees are anticipated to be ready for field planting in September of this year.����


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