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: 10/13/2021
Project: 18-028C   Year: 2021
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. We are working on completing the analysis of data from trials 2 and 3 to be included for publication of three years of field data. The most time-consuming task is the analysis of root images captured with the minirhizotron system, which is still ongoing.     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.We continued our monthly root growth measurements with the rhizotron imaging system and their analysis. We are still working on the PCR and ELISA assays.Much of the time in this quarter was spent on devising a methodology to simulate wind-induced uprooting for our upcoming evaluations. We practiced on similar-sized trees at our research center to test different strategies and finalized a method that uses winching to pull trees while measuring and recording the exact force over time; this method will be combined with videotaping each excavation event.   2. Please state what work is anticipated for next quarter: We will conduct the pull-over (to simulate wind-induced uprooting) of trees in our 2-year-old field trials. Prior to pulling-over the trees, biometric data will be collected (tree height, canopy volume, trunk diameters) and leaves will be collected for nutrient analysis and CLas detection. After pulling-over the trees, we will severe the root crowns for detailed analysis in the lab (to examine the relationship of root structure and anchorage strength). 3. Please state budget status (underspend or overspend, and why): Approximately 75% of funds have been spent, which is underspent due to Covid-19 related complications that affected research, travel, and hiring of personnel.  


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