Agronomical, Physiological and Biochemical Characterization of In Vitro Selected Eggplant Somaclonal Variants under NaCl Stress.

Previously, an efficient regeneration protocol was established and applied to regenerate plants from calli lines that could grow on eggplant leaf explants after a stepwise in vitro selection for tolerance to salt stress. Plants were regenerated from calli lines that could tolerate up to 120 mM NaCl. For further in vitro and in vivo evaluation, four plants with a higher number of leaves and longer roots were selected from the 32 plants tested in vitro. The aim of this study was to confirm the stability of salt tolerance in the progeny of these four mutants ('R18', 'R19', 'R23' and 'R30'). After three years of in vivo culture, we evaluated the impact of NaCl stress on agronomic, physiological and biochemical parameters compared to the parental control ('P'). The regenerated and control plants were assessed under in vitro and in vivo conditions and were subjected to 0, 40, 80 and 160 mM of NaCl. Our results show significant variation in salinity tolerance among regenerated and control plants, indicating the superiority of four regenerants ('R18', 'R19', 'R23' and 'R30') when compared to the parental line ('P'). In vitro germination kinetics and young seedling growth divided the lines into a sensitive and a tolerant group. 'P' tolerate only moderate salt stress, up to 40 mM NaCl, while the tolerance level of 'R18', 'R19', 'R23' and 'R30' was up to 80 mM NaCl. The quantum yield of PSII (Φ