Grapevine (Vitis spp.) is one of the most important socio-economically important plants in the global scale, and the need for its breeding is increasing. In viticulture, mutation is more promising than crossbreeding in breeding new genotypes from natural genetic diversity. Polyploid plants outperform their diploid relatives in several respects. In this study, the efficacy of oryzalin and N2O mutagens in the induction of polyploidy was investigated by applying different doses and durations to the forced cuttings of 41B [Chasselas (Vitis vinifera L.) × Vitis berlandieri Planch)] and Fercal [(Vitis vinifera x Vitis berlandieri) × 333 EM] rootstocks. LD50 values of mutagen applications were determined, morphological and cytological effects were examined by macroscopic, microscopic, and cytological methods. Application time and dose increase of mutagens decreased LD50 values. As a result of mutagen applications, leaf thickness and chlorophyll content of the surviving plants increased. Applications increased stomatal sizes, decreased their density, increased chloroplast numbers, increased leaf thicknesses and partially SPAD values. It was determined that they were not polyploid in the confirmation test performed with flow cytometry (FC) analyses in 4 Fercal and 1 41B samples that were assumed to be mutant by stoma and chloroplast examinations. After that, it was thought that it would be appropriate to try vegetative material with actively dividing cells, such as nodal cuttings, in the studies of obtaining polyploid individuals on grapevine rootstocks