One-year-old trees of Pyrus calleryana ‘Bradford’, ‘Aristocrat’ and ‘Redspire’ on ‘OHF 97’ rootstock were treated in a nursery with foliar sprays of Promalin at 750 or 1500 ppm ai or dikegulac-sodium (Atrimmec) at 1440 or 2880 ppm ai in June 1989. Untreated trees of the three pear cultivars averaged less than one branch per tree at the end of the season, while ‘Bradford’ and ‘Aristocrat’ treated with Promalin at either concentration averaged over 10 and ‘Redspire’ averaged 9. Dikegulac promoted branching of all cultivars however, unlike Promalin, reduced tree height and resulted in visibly narrower branching angles.

branching, feathering, Promalin, Atrimmec, growth regulators
Callery Pear (Pyrus calleryana L.)
Promalin (BA + GA4+7), N-(phenylmethyl)-1H-purin-6-amine + (1α,2β,4aα,4bβ,10β)-2,4a,7-trihydroxyl-1-methyl-8-methylenegibb-3-ene-1,10-dicarboxylic acid 1,4a-lactone, Atrimmec (dikegulac), 2,3:4,6-bis-O-(1-methylethylidene)-a-L-xylo-2-hexulofuranosonic acid
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Author notes

University of Missouri Agricultural Experiment Station Publication No. 12,007.

2Research Specialist. Present address: Department of Horticultural Sciences, New York State Agricultural Experiment Station, Geneva, NY 14456

3Associate Professor of Horticulture, Plant Science Unit, University of Missouri, Columbia, MO 65211.

4Research Assistant Professor, University of Missouri, Columbia, MO 65211.

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1994