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: 11/15/2022
Project: 21-007   Year: 2022
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.2) To determine effects of GA3 and 2,4D applications on fruit retention when applied at different times during fruit development.3) To develop a strong and proactive outreach program.  For objective 1 we did the new set of treatments by the end of September in Hamlin. As before, every set of treatments is performed in an independent block, so treatments are applied only once, to assess the best timing to achieve the best results. Trees under Zn and Zn+K treatments continue having greener canopies. Control trees are presenting some off-blooms still in September and October with new fruit set clearly present. These off-blooms have not been observed in the treated trees. Fruit drop is being recorded in Hamlin. Unfortunately, hurricane Ian has increased fruit drop but since we are collecting data weekly, we are going to be able to reduce the fruit drop background noise and in any case, see if our treatments had a beneficial impact even under hurricane conditions in alleviating fruit drop. We have lost also some trees due to the high wind. Interestingly, all of the trees were lost in a control plot. We do not have a clear explanation for this, but fortunately, treatments were not compromised and other trees in untreated plots are being used as new control replacements. In objective 2, GA3 and 2,4D treatments have continued as planned. Objective 3. Outreach-Citrus Grower Forum. Citrus Fix. Guest speakers Vashisth and Alferez. Invited by AMVAC. SWFREC, August 30.-Citrus Grower Forum. Citrus Fix. Guest speakers Vashisth and Alferez. Invited by AMVAC. Stuart Conference Center, Bartow, August 31.   2. Please state what work is anticipated for next quarter: In next quarter,  we will perform the December treatment in Valencia for objective 1 and continue treatments for  objective 2, and we will continue assesing fruit drop in Hamlin.     3. Please state budget status (underspend or overspend, and why): We are still underspending as the student joined late. As we start our analysis we will be spending more funds this quarter.   


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