Abstract
Cytokinin, N-[2-isopentenyl] adenine (2iP), increased and anticytokinin, 4-chloro-2-cyclobutylamino-6-ethylamino-s-triazine (CCET), retards tillering of barley. Tillering was also shown to be retarded by auxin, α-naphthalene acetic acid (NAA) and promoted by antiauxin, 2, 3, 5-triiodobenzoic acid (TIBA). TIBA and 2iP treatment promoted tillering by altering the parallelism of leaf emergence between main stem and tiller ; and the tillering itself, including secondary or tertiary tillers, was hastened which resulted in more tillers being produced at high leaf positions where the untreated control plants had not produced any tillers. Conversely anticytokinin CEET and auxin NAA inhibited or delayed the release of tiller buds even when corresponding leaves on the main stem had already developed to the point where tiller buds normally occur.
