The 2012 ASHS Annual Conference

Needle abscission in Balsam fir Christmas trees has recently become a challenge to the Christmas tree industry. Postharvest needle loss is a complex phenomenon involving interactions among genotypic, environmental, postharvest conditions altering the physiological processes involved in needle abscission. The objective of these experiments was to evaluate several needle abscission prevention agents (NAPA) compounds to determine the effective compounds and concentration for improved needle retention. Two year old branches were used to evaluate four NAPA compounds (NAPA-101; NAPA-102; NAPA-103; NAPA-104) at 0, 1, 10, 100, 1000, and 10, 000 micromolar concentrations. Each treatment for each of the compounds was replicated three times. NAPA-101 did not show a significant difference; however, the 10 micromolar concentration was the most effective as needles lasted 20 days longer than the control. NAPA-102 did show a marginal significant difference and the 100 micromolar concentration significantly improved needle retention compared to other concentrations. Branches treated with 100 micromolar concentration of NAPA-102 lasted more than 80 days compared to the control which lasted for 60 days. Needle retention was significantly higher in branches treated with NAPA-103 at the 0, 1, and 10 micromolar than the ones treated with other concentrations, and the 10 micromolar concentration had needle retention over 70 days. NAPA-104 did not show any improvement in needle retention as the controls lasted longer than the other concentrations. Overall, NAPA-101 and NAPA-103 showed a 10 to 20 day improvement in needle retention at the 10 micromolar concentration. NAPA-102 also showed a 10 to 20 day improvement in needle retention, but was at the 100 micromolar concentration. It is speculated that these compounds may act by inhibiting ethylene synthesis and/or preventing auxin degradation.