Morpho-physiological characterization of chilli genotypes under NaCl salinity

Salinity is a stringent abiotic stress that limits plant growth and development. Present study was undertaken to explore morpho-physiological responses of different chilli (Capsicum annum L.) genotypes to NaCl-induced salinity. Seedlings of six chilli genotypes (Loralai, Sanam, Desi, Kundri, Asia Bok and Magnum) were subjected to five NaCl salinity levels (0, 25, 50, 75 and 100 mM). A separate control for each genotype was maintained for comparison. Increasing salinity levels significantly reduced shoot and root elongation as well biomass accumulation. Transpiration rate, stomatal conductance, photosynthetic activity and chlorophyll contents were also reduced although genotype-specific responses were evident for these attributes with the exception of photosynthetic rate. At upper limits of salinity (100 mM), Desi and Loralai genotypes produced more shoot and root length and higher fresh and dry biomass than rest of the chilli genotypes. Moreover, comparatively higher stomatal conductance and transpiration rate were also observed for these genotypes at all salinity levels. Desi and Loralai genotypes accumulated less Na^+ and higher Ca^2+ and K^+ ions than other chilli genotypes. Based on various parameters studied, Desi and Loralai genotypes appeared to be promising salt-tolerant chilli genotypes.