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

Micropropagation is a tool for large-scale reproduction of planting material for viticulture sustainability. Successful micropropagation depends on the continued productivity of plantlets during the acclimatization phase. Due to high humidity in the culture container and free water in the environment, it causes rapid water loss and drying of plantlets with watery stems and leaves, poorly developed cuticle, large intercellular space, and incomplete stomata. Acclimatization of in vitro grown plantlets is often difficult. Silicon is gaining in importance as a useful tool in coping with multiple stress factors in different plant species, due to its contribution to the formation of the cuticle of plants, its mechanical resistance to biotic and abiotic stress, and its contribution to the flow of water through stomata and plant surfaces. In this study, the effects of 500 and 1000 µL ortho silicon applications at the acclimatization stage on in vitro propagated plantlets of 41B, 110R and Fercal grapevine rootstocks were evaluated by examining their survival rates. In the in vitro propagation process, rooting rates were listed as Fercal (64%) and 110R (32%) and 41B (28%) according to rootstocks, while root numbers were listed as Fercal (11.8), 41B (8.5), 110R (3.6). Genotypic differences were determined in the effects of silicon on plantlets in the acclimation process. In 110R and Fercal control plantlets, all plantlets were lost during acclimatization. Of the plantlets treated with 1000 µL SiO2, 110R 66% Fercal 88% and in 41B, the control, 500 and 1000 µL SiO2 applied plantlets survived 100%, 66% and 66%, respectively. 1000 µL SiO2 dose was more effective on survival rates than 500 µL applications. In subsequent studies, it was found that 1000 µL SiO2 applications could be used for practical success in grapevine genotypes that had problems in acclimatization and in other in vitro propagation studies.

Table grapes are one of the most consumed non-climacteric fruits globally, and practices for their quality are socioeconomically important. In this study, the effects of the combined and separate applications of two plant activators Ortho Silicon (Si, Optysil, 0.5 mL L-1) and Ascophyllum nodosum-based seaweed extract (ANE, KelpGreen 2.5 ml L-1) were tested by two applications after fruit set 15 days intervals to table grapes cvs. Gök Üzüm and Müşküle in a producer vineyard at Hadim town of Konya province in middle Anatolia37°2'15"N 32°34'53" E, 1060 m above sea level. The effects of the applications on ripening, cluster and berry characteristics and post harvest shelf life during 10 days of storage at room conditions were analyzed. Both plant activators provided an increase in cluster size and an improvement in ripening. Si+ANE was more effective on the maturation and quality retention during the post-harvest shelf-life period. All applications provided reduction in weight loss (WL), decay rate and berry dullness, and it reduced berry separation force due to the drying of the peduncle and decreased the maturity index (MI) increase in the post harvest period. Thus, it contributed to the formation and retention of fruit quality. According to the data obtained from this study, improvements in the sustainable preservation of table grape quality can be achieved by applying Ortho Silicon and A. nodosum based seaweed extract separately and together between after fruit set and before veraison.