California Pepper Commission


Proposal Weir CA Pepper Commission

Research Proposal to Evaluate abscission Layer Products for Red Bell Peppers 2015

To: California Pepper CommissionFebruary 18, 2015

From: Bill Weir, Ph.D.

Re: Research Proposal Introduction:

Approximately ten to fifteen percent of bell peppers are marketed as reds. They are harvested in July and again at the end of summer due to high summer temperatures.

Increases in synthesis and concentrations of ethylene lead to maturity and the formation of an abscission zone between the fruit stem and the plant. Auxins work counter to ethylene and can cause delayed maturity.


Fruits of red bell peppers are soft and tender enough to pull away from the calyx during harvest rendering them unmarketable. Also, stems are tough at maturity causing the stem and calyx to be left behind on the plant. Formation of an abscission zone in the stem could allow the stem-to-plant connection to be weakened so that fruits could be harvested more easily with less damage.


Research tests will be conducted in pepper applying the following abscission producing products in a replicated field trial. IBA will be included since it resulted in earliness and increased yields in 2014 trials. The following treatments will be employed.

  1. Untreated check
  2. Abcissic Acid
  3. Ethylene
  4. One of the cotton abscission products
    Cotton Quik, Quik Pick, Prep, Finish or Dropp
  5. Indolebutric Acid (IBA)


Two bell pepper growers in the Le Grand area are: Giampouli, and Marchini

Field testing is commonly conducted for $1000.00 per treatment, which covers all costs incurred by the researcher. The budget is as follows:

Plot location and set up $1000.00
Labor for applications $500.00
Labor for harvests $1500.00
Data analysis and report $1000.00
Travel and Miscellaneous $1000.00
Total $5000.00

Bill L. Weir, Ph.D.

University of California Cooperative Extension


Phone- 209 777 7950

e-mail - or

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