The Effect of Plant Growth Regulating Chemicals on Rose Shoot Development from Basal and Axillary Buds1

Abstract

2,3,5-triiodobenzoic acid (TIBA), (2-chloroethyl) phosphonic acid (ethephon), 6-(benzylamino) - 9 - (2-tetrahydropyran-yl) - 9 H-purine (PBA), and N 6 benzyl adenine (N 6 BA) were applied to greenhouse rose cvs. Red American Beauty, Forever Yours, Mary DeVor and Jack Frost as sprays, lanolin paste, and in solutions in floral foam. Axillary shoot development was significantly increased when PBA and N 6 BA were applied as sprays, in paste or in solutions in floral foam. The most significant response was obtained when the chemical solutions were absorbed from floral foam cubes attached to a cutback rose cane. Most of the axillary buds broke dormancy when the growth regulating chemicals were applied by this method, however, many of the developing buds stopped growth before becoming shoots. Chemicals PBA and N 6 BA significantly increased the development of flowering and blind shoots for all rose clones. Plant growth regulating chemicals, methods of application, and concentrations favorable for the development of axillary shoots had no comparable effect on basal shoots developing from the rose bud union.