USAGE OF MICROBIAL BIOSTIMULANTS FOR PLANT GROWTH IN PETUNIA UNDER DROUGHT STRESS CONDITIONS

Petunia is one of the most popular ornamental plants used in containers, hanging baskets, wall decoration, borders, as a seasonal ground cover in the garden due to its various flower colours and patterns and has an important commercial value. However, it shows high sensitivity to drought stress. The present study was conducted to determine the effects of mycorrhizae and rhizobacteria applications against drought stress in Petunia hybrida 'Super Cascade White'. For drought stress, restricted irrigation was applied to the plants at the rates of 100%, 75%, 50% and 25%. In a result of the research, as the amount of water stress increased, there was a negative effect on all parameters (plant height, number of leaves, number of flowers, petal length, petal width, plant fresh and dry weight, root fresh and dry weight, root length) examined. Applying mycorrhizae and rhizobacteria separately or in combination reduced this negative effect. It was concluded that mycorrhizae + rhizobacteria (plant and root fresh/dry weights, root length) treatments for underground parts; separate applications of rhizobacteria (leaf, flower number and petal length) and mycorrhizae (plant height, petal width) treatments for aboveground parts are the most effective applications. When it comes to water stress, we found that a 75% water restriction treatment gives the best results on petunia morphological traits after control plants treated with 100% water. In this respect, the application of microbial bio stimulants with 25% less water is sufficient for resistance to abiotic stress conditions in petunias.