Reducing fruit drop by altering hormonal responses within the tree through nutritional and hormonal therapies: a mechanistic affordable approach

Reducing fruit drop by altering hormonal responses within the tree through nutritional and hormonal therapies: a mechanistic affordable approach

Report Date: 08/14/2024
Project: 21-007   Year: 2024
Category: Horticultural & Management
Author: Fernando Alferez
Sponsor: Citrus Research and Development Foundation

1. Please state project objectives and what work was done this quarter to address them: Specific objectives are: 1) To determine the right timing for Zn and K treatments to minimize fruit drop.We started analyzing auxin content in Valencia and Hamlin. For Hamlin, we see a 3-fold increase in IAA content in both abscission zone and flavedo around October and November, when treatments of Zn+K are performed in late september-early October. This is transient but is coincident with a decrease in fruit drop. In Valencia results are less clear and we are still analyzing samples, but we see this IAA increase around late February following Zn+K treatment.2) To determine effects of GA3 and 2,4D applications on fruit retention when applied at different times during fruit development.After harvesting was finished we have started planning the new set of treatments and selected the plots to start treatments in the coming quarter. 3) To develop a strong and proactive outreach program. -Alferez F. New tools for growing citrus under endemic HLB, Davie UF Extension, Master Gardener Talk Series, June 4, 2024.-Otavio de Sousa, M., Alferez F. 2024. Fine-tuning zinc and potassium treatments to increase yield in sweet orange FSHS annual meeting, June 2024, Orlando. 2. Please state what work is anticipated for next quarter: We will resume treatments in objectives 1 and 2, characterize tree health, and continue auxin analysis. 3. Please state budget status (underspend or overspend, and why): Budget continues on track  


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