IDENTIFICATION OF POTATO BREEDING LINES WITH TOLERANCE TO HYDRIC STRESS UNDER IN VITRO CONDITIONS

In this research our aim was to identify genotypes with hydric stress tolerance in vitro among 44 potato breeding lines. The study involved the number of leaves / plantlet, plantlet length and root growth of plantlets. Polyethylene glycol (6000) was used for exerting the hydric deficiency stress on the in vitro plantlets. Different levels of hydric stress were induced using two concentrations (1% and 2%) of polyethylene glycol (PEG) added in Murashige-Skoog medium. The values obtained for the mentioned traits analyzed on medium with PEG were compared with Murashige-Skoog medium (control). Under osmotic stress, all the measurements for number of leaves / plantlet, plantlet length and root growth of plantlets presented lower values, compared to the control medium (MS), with very significant negative differences. Genotypes 1893/5 and 1901/3 were less affected by the treatment with PEG (with the highest concentration) for all parameters taken in the study. These genotypes, which showed good tolerance to the hydric stress in vitro will be tested in next years in the field, to establish how close is the correlation with field performance under drought.