This study was conducted both in field and greenhouse conditions at Atatürk University, College of Agriculture, Erzurum, Turkey, during 2004 and 2006. The objective of this study was to determine the effect of some bacteria isolates on root formation, root length and dry matter content of roots of mint (Mentha piperita L.). Mint and Agrebacterium rubi (strain A16), Burkholderia gladii (strain BA7), Peseudomonas putidea (strain BA8), Bacillus subtilus (strain OSU142) Bacillus megatorium (strain M3) were used as rooting agent, respectively. The highest rooting percentage was obtained by application of A16 (88.70; 89.85%), M3 (86.12; 91.15%) and BA8 (87.27; 87.77%). Overall, the lowest was observed in controls (79.31 and 76.96). Root length was greater when cuttings were treated with BA7, A16 and M3 compared to the other treatments. Mint cuttings inoculated with M3 had more dry matter content than control and the other treatments in both experiments. Rooting performance, root length and dry matter content of root, cuttings of mint treated with bacterial solutions showed better performance than control cuttings in both experiments. In addition, when evaluated bacteria strains were compared, M3 was found more effective than the others on the examined properties.

Key words: Bacteria strains, cutting, PGPR, Mentha piperita L.