Title: Ethylene Generation, Temperature Responses, and Relative Biological Activities of Several Compounds with Potential for Promoting Abscission of Sour Cherry Fruit1
Abstract: Abstract Five compounds were evaluated for consistent promotion of sour cherry ( Prunus cerasus L. cv. Montmorency) fruit abscission under field conditions: (2-chloroethyl)phosphonic acid (ethephon); 2-chloroethyl-tris-(2-methoxyethoxy)-silane (CGA 13586); 2-chloroethyl-methylbis-(phenylmethoxy)-silane (CGA 15281); 1,1,5,5-tetra-methyl-3-dimethylaminodithiobiuret (ER 3952), and beta-hydroxyethylhydrazine (BOH). The compounds were applied to mature trees at equimolar concentrations, and rates of ethylene evolution, effects of temperature on rates of ethylene evolution, and fruit removal forces were measured. Ethephon generated ethylene at adequate rates and was a good promoter of fruit abscission, but its activity was markedly affected by temperature. CGA 15281 promoted fruit abscission with minimal effect of temperature on ethylene evolution. ER 3952 was also a good fruit loosener, although it did not release ethylene directly. CGA 13586 and BOH were not effective in promoting fruit abscission and were poor ethylene generators.