EFFECT OF PLANT GROWTH PROMOTING RHIZOBACTERIA ON GROWTH, NUTRIENT, ORGANIC ACID, AMINO ACID AND HORMONE CONTENT OF CAULIFLOWER (Brassica oleracea L. var. botrytis) TRANSPLANTS

This study was conducted to determine the effect of different plant growth promoting rhizobacteria (PGPR) strains on growth and quality of cauliflower transplants under greenhouse conditions. The strains of Bacillus megaterium TV-3D, B. megaterium TV-91C, Pantoea agglomerans RK-92, B. subtilis TV-17C, B. megaterium TV-87A, B. megaterium KBA-10 were used in this study. The results of this study showed that different bacterial inoculations increased plant growth parameters such as fresh shoot weight, dry shoot weight, root diameter, root length, fresh root weight, dry root weight, plant height, stem diameter, leaf area and chlorophyll contents of cauliflower transplant respectively. Except for abscisic acid (ABA), the values of gibberellic acid (GA), salicylic acid (SA), indole acetic acid (IAA) was increased by ratio of 23.64, 89.54 and 25.63%, respectively in compared to the control by application of B. megaterium KBA-10 and P. agglomerans RK-92. The amount of organic acids with B. subtilis TV-17C PGPR applications have increased at a ranging ratio from 9.63 to 186.02%. Also, PGPR inoculations increased the macro and micro nutrient content of cauliflower transplants. As a result, the use of bacteria treatments may provide a means of improving transplant growth and quality in cauliflower.