Abscission :: Screening Alternate Abscission Compounds

The abscission program has an active screening program. Compounds selected for screening are based on available chemistries identified either by us or provided by agrochemical industries. Information learned about the citrus abscission process from the physiological and molecular component of the program has also allowed us to identify additional compounds for screening. Although many compounds we have screened are synthetic, emphasis has been put on discovery of 'natural' compounds because their registration is likely to be less costly and time consuming.

Objectives

• To identify environmentally friendly, non-phytotoxic abscission agents for Florida citrus and other commodities

Key Findings (Updated on 09/10)

Research focused on screening compounds selected on the basis of metabolism affected by CMNP, the model selective abscission agent. Agents are selected routinely, and their efficacy determined on citrus and other tree fruit commodities. We are providing information identifying environmental factors that control abscission. Together with previous research, this can be used to better predict and control the abscission process. Our expertise in abscission and mechanical harvesting has been used to assist other fruit crop commodities that are seeking to control abscission and mechanize the harvesting process.

Activities Planned for 2010-2011

• Continue screening potential abscission agents applied on fruit, limbs and whole tree canopies to determine efficacy.
• Evaluate phytotoxicity and yield effects.

Publications and Extension Products

Research:

Gonzalez-Herranz R, Cathline KA, Fidelibus MW, Burns JK (2009) Potential of methyl jasmonate as a harvest aid for 'Thompson Seedless' grapes: Concentration and time needed for consistent berry loosening. HortScience 44:1330-1333.

Karuppiah K-J, Burns JK (2009) Differential ethylene-related gene expression, MACC, and ACC content in fruit flavedo of 'Fallglo' and 'LeeXOrlando' citrus hybrids. 2" International Citrus Biotechnology Symposium, November 30-December 2, 2009. Catania, Italy. Poster presentation.

Kostenyuk lA, Burns JK (2009) Downregulation of ACC oxidase in citrus reduces wound-induced ethylene production and leaf abscission. 2" International Citrus Biotechnology Symposium, November 30-December 2, 2009. Catania, Italy. Poster presentation.

Rosales R., Liao H-L, Burns JK (2009) IAA, ABA, and ethylene content and related gene expression is altered in mature fruit fractions of Huanglongbing-infected Citrus sinensis. 2nd International Citrus Biotechnology Symposium, November 30-December 2, 2009. Catania, Italy. Poster presentation.

For more information:

Contact Jacqueline Burns