Flower Bud Formation, Flowering, and Fruiting in Highbush Blueberry in Response to Chlormequat, Ethephon, and Daminozide

Abstract Midsummer application of butanedioic acid mono-2,2-dimethylhydrazide (daminozide), 2500 ppm, or (2-chloroethyl)trimethylammonium chloride (chlormequat), 3000 ppm, with or without (2-chloroethyl)phosphonic acid (ethephon), 2000 ppm, were applied to highbush blueberry ( Vaccinium corymbosum L.) ‘Stanley’ and ‘Bluecrop’. Flower bud set and flower number were increased by daminozide on both cultivars. ‘Stanley’ plants showed an increase in numbers of fruit per shoot and total yield. Ethephon generally did not interact with growth retardants, but evoked a response similar to daminozide in ‘Bluecrop’.