3.3.3. Changes in the SI of Root Length (SIRL)

About half of the breeding lines responded to 0.1 M D-mannitol with significant decreases in their root length, but the SIRL values of two breeding lines were significantly increased (Table 12, Figure S11a). One of them (C63) showed significantly a higher result than the C103 referent line, although the C103 referent line also responded with increased root length. However, as D-mannitol concentration increased, the SIRL values decreased, mostly significantly (Table 11, Figure S10a–c). When 0.2 M D-mannitol was applied, only the C103 referent line showed SIRL values higher than 100, but the SIRL values of C17 and C63 breeding lines did not differ significantly. Decreased SIRL values were found at this level of D-mannitol in almost all breeding lines. SIRL values of breeding lines C17 and C63 were significantly higher than those of the C107 referent line, and increased SIRL values were detected in more than half the of breeding lines. At the highest D-mannitol level (0.3 M), each genotype involved in the experiment showed decreased SIRL values, and we found significantly higher SIRL values in more than a third of the breeding lines compared to the C103 referent line.

**Table 12.** Root length SI (SIRL) values of potato genotypes under stress treatment induced by Dmannitol added to the medium at levels of 0.1 M, 0.2 M and 0.3 M.



**Table 12.** *Cont.*

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.
