EFFECTS OF GIBBERELLIN-A3, PACLOBUTRAZOL, CHLORMEQUAT, AND NUTRITIONAL LEVELS ON THE GROWTH OF RHODODENDRON BADEN-BADEN

Effects on growth, flower bud initiation and flowering of Rhododendron 'Baden-Baden' plants were studied by investigating four nutritional l evels and treatments with paclobutrazol, paclobutrazol and GA3, GA3, a nd chlormequat. One application of 250 mg/l paclobutrazol and four app lications of 400 mg/l chlormequat retarded growth. Growth retardation by paclobutrazol was partly and temporarily reversed by an application of GA3. Plants treated with both paclobutrazol and GA3 produced more flower buds and sometimes flowered better than untreated plants or pla nts treated with either paclobutrazol or GA3 alone. All plants in the greenhouse developed faster than those outside, except those treated w ith paclobutrazol. Increasing fertilization beyond the recommended lev el did not influence plant growth, but plants treated with growth regu lators used more macroelements than untreated ones.