The effect of some beneficial bacteria on plant growth and flowering in seasonal ornamental plants grown in soilless culture

The use of synthetic fertilizers in agricultural production is becoming a major threat to the environment, humans, and other living beings. In this regard, the use of PGPRs has become increasingly important in recent years for ensuring soil sustainability and the continuity of resources. It has been observed that root bacteria cultivation, which promotes plant growth, is widely used in the cultivation of difficult-to-produce fruits, vegetables, and field crops. However, studies on its use in ornamental plants are quite limited. Therefore, in this study, it was aimed to determine the effects of PGPR applications on plant growth and flower quality of some summer and winter seasonal ornamental plants grown in soilless culture. As plant material, the varieties Bellis perennis L.'Deep Rose', Begonia semperflorens F1 'Nightlife Red', and Petunia hybrida 'Surfinia Blue' were used. The study was designed according to a randomized block design; for each plant species, there were 10 applications (8 PGPR (Bacillus megaterium, Bacillus amyloliquefaciens, Bacillus subtilis, Azotobacter chroococcum+Azotobacter vinelandii) applications, positive and negative control applications) with 3 replications and 10 plants per replication. For each plant variety, data were collected by performing morphological measurements related to plant and root formation on the plants that were uprooted during and at the end of the production period, focusing on plant development, flowering status, and flower quality.PGPR applications have provided early flowering in sugar plate, sugar begonia, and petunia plants. In the sugar plate, when comparing PGPRs with the control group (positive and negative), it has been determined that the highest values in many criteria such as the number of leaves, plant fresh and dry weight, root length, fresh and dry weight, number of flowers, and flower diameter were found in the PGPR applications. It has been determined that the sugar begonia has the highest values of flower fresh and dry weight, flower diameter, flower count, plant height, plant dry weight, root dry weight, leaf count, branch count, and early flowering in the PGPR application groups. In petunia plants, the effects of PGPR and control group applications on root length, plant height, and dry weight characteristics were found to be insignificant and were observed to fall within the same statistical group. In petunias, it has been determined that bacterial applications have significant effects on the parameters of flower count, root age, and dry weight. In the cultivation of Bellis perennis L. 'Deep Rose', Begonia semperflorens F1 'Nightlife Red', and Petunia hybrida 'Surfinia Blue' varieties, it has been demonstrated that PGPR applications have positive effects on plant growth, flowering, and plant-flower quality characteristics.With new studies to be conducted, the aim should be to determine suitable PGPR strains and doses for these species and other seasonal plant types, as well as to identify the effects of bacterial applications on the use of plants in soilless agriculture.