Height Control In Three Pepper Types Treated with Exogenous Abscisic Acid

Vegetables transplants can become tall and leggy prior to field establishment, producing challenges for the growers using mechanical transplanter to establish their crops. Thus, controlling the height of vegetable transplants prior to planting could be an advantage for commercial vegetable growers. A greenhouse experiment was conducted in 2008 and 2009 to determine the efficacy of exogenous abscisic acid (ABA) applications for height control of three transplanted pepper types. Three types of peppers (Capsicum annuum L.) were investigated: bell pepper (cv. Aristotle), Jalapeño (cv. Grande) and banana pepper (cv. Pageant).  Ten ABA treatments were evaluated, based on application frequency and timing over an 8-week period, and an untreated control were arranged in a randomized complete block design with six (2008) or five (2009) replications. Treatments included: single application at Week 1 (cotyledon stage), Week 2, Week 3, and Week 4: double applications were made at Week 1 + 2, Week 2 + 3, and Week 3 + 4; and multiple applications of ABA at Week 1 + 2 + 3, Week 2 + 3 + 4, and Week 1 + 2 + 3 + 4.  Early, single dose applications (Week 1) were more effective at controlling height than a single dose applied later. Multiple ABA applications initiated early (at the cotyledon stage) of Aristotle bell peppers were effective in reducing transplant height compared with a single ABA application. Differences among the response of pepper types to ABA application were observed.  Aristotle showed significant treatment effects even six weeks after treatment.  Pageant (banana pepper) exhibited an intermediate response with effects lasting only two weeks. No significant height reductions due to ABA treatment were observed for Grande (Jalapeño pepper). Multiple ABA dose applications initiated at the cotyledon plant growth stage can be used to effectively reduce transplant height of Aristotle bell pepper seedlings.