*3.3. Effect of Osmotic Stress Induced by D-Mannitol in In Vitro Shoot Cultures*

3.3.1. Changes in the SI of Survival Rate (SISR)

The survival rates of the shoot cultures were not significantly affected by any concentration of D-mannitol in the case of about 41% of the breeding lines, and in fact, each explant survived in all treatments in five breeding lines (C2, C8, C20, C30 and C63) (Table 10, Figure S9a–c). Using D-mannitol at a concentration of 0.1 M resulted in significantly lower survival in C9, C21, and C58 and in referent line C107 than in referent line C103. A remarkable number of the breeding lines showed significantly higher SISR values than the C107

referent line. In the treatment with 0.2 M D-mannitol, significantly lower SISR values were observed in three breeding lines (C6, C22 and C35) and the C107 referent line compared to their respective values obtained with the 0.1 M and 0.2 M D-mannitol levels. When 0.3 M D-mannitol was applied, decreased SISR values were found in 12 breeding lines and in the C103 referent line. Moreover, all tested genotypes showed significantly higher SISR values compared to the C107 referent line.

**Table 10.** Survival rate SI (SISR) values of potato genotypes under stress treatment induced by D-mannitol added to the medium at levels of 0.1 M, 0.2 M and 0.3 M.


Symbols mark significant differences from the C107 referent line (-), or from the C103 referent line () according to LSD test; the small letters indicate significantly different means between the breeding lines within a treatment, and the capital letters indicate significantly different means between treatment levels within a breeding line according to Tukey-B test.
