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: 07/08/2020
Project: 18-028C   Year: 2020
Category: Plant Improvement
Author: Ute Albrecht
Sponsor: Citrus Research and Development Foundation

 1. Please state project objectives and what work was done this quarter to address them: Objective 1. Investigate effects of rootstock propagation method and the interaction with rootstock on root structure, root growth, and tree performance during the first 3 years of growth in the field. Bimonthly root growth measurements with the rhizotron imaging system continued in trial 2 (Hendry County) and trial 3 (Polk County). All 2-year horticultural evaluations for trials 2 and 3 were completed and data analysis is in progress. Preliminary data suggest that the propagation method does not have a significant influence on tree growth and health during the first 2 years of growth. In contrast, significant rootstock effects were observed. For some of the rootstocks, effects differed by location. For example, US-942 and X-639 appear to perform better at the Hendry County location than the Polk County location. A Citrus Industry magazine article was submitted, which is to appear in the August 2020 issue. The article contains information on root architectures of field-ready plants and after 2 years of field growth (trial 1). These data are currently being prepared for publication in a peer-reviewed open-access journal.      Objective 2. Investigate if trees on rootstocks propagated by tissue culture or cuttings differ in susceptibility to Phytophthora-induced decline or wind-induced blow-over compared with trees on rootstocks propagated by seed. Trial 4 (planted in Nov 2019) is in progress and trees are growing well. Root growth measurements with the rhizotron imaging system continued.    2. Please state what work is anticipated for next quarter: We will be collecting root core samples for root mass determination and analysis of fibrous root structure in all trials. Rhizotron image analyses will continue.  Leaf samples will be collected for nutrient analysis.   3. Please state budget status (underspend or overspend, and why): Approximately 40% of funds have been spent. One personnel left and we were not able to rehire yet due to covid-19 related complications.    


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