Highly efficient in vitro tetraploid plant production via colchicine treatment using embryogenic suspension cultures in grapevine (Vitis vinifera cv. Mencia)

In vitro chromosome doubling techniques have been used to produce polyploids in several species, including table grapes, but limited research in this field has been performed using winegrapes. An efficient procedure was established to induce tetraploid grapevine plants by colchicine treatment of embryogenic cell aggregates (ECAs) grown in winegrape cultivar (cv. Mencia) suspension cultures. Colchicine treatment caused a significant decrease in the survival and embryogenic potential of the ECAs compared with the control. However, plantlets were regenerated and assessed for ploidy level by flow cytometry. Almost all plants not treated with colchicine maintained their ploidy level, whereas colchicine treatment resulted in a high variation in ploidy level. Colchicine at 0.2 % was the most effective concentration for obtaining tetraploid plantlets (25 % tetraploids). No chimeric or mixoploid plantlets were detected in this study. Based on the unique cell origin of grapevine somatic embryos, our system prevented obtaining chimeric plants. This protocol allows an increase in grapevine genetic diversity and could be a valuable tool for improving this crop. To our knowledge, this is the first report on in vitro chromosome doubling by colchicine treatment of embryogenic cell aggregates growing in grapevine suspension cultures.