Evaluation of Chrysanthemum morifolium varieties for salinity tolerance under hydroponic system

Salinity tolerance of 22 varieties of chrysanthemum (Chrysanthemum morifolium Ramat.) was studied in National Phytotron Facility, ICAR-Indian Agricultural Research Institute, New Delhi at five different salinity levels (0, 50, 100, 150, 200 mmol/L). Salt tolerance was identified by measuring changes of different physiological as well as morphological parameters such as chlorophyll, proline, MSI (Membrane Stability Index), shoot length, root length, dry weight, etc. In the present study, it was found that the amount of chlorophyll a, chlorophyll b and total chlorophyll decreased with increase in the amount of salt concentration. At 100 mmol/L NaCl, the highest total chlorophyll content was found in Pusa Aditya, Haldighati, Lalit, Little Pink and Jaya, whereas lowest was observed in Pusa Sona, Yellow Gold and Himanshu. The rate of reduction in dry weight is dependent on the level of stress and variety. The greatest reduction in dry weight was found under 200 mmol/L NaCl treatment. The MSI reduced up to 47.64% under 200 mmol/L NaCl treatment from 85.65% of control. Reduction in MSI with increase in salinity may be due to high electrolyte leakage from cells of susceptible varieties. An increase in Proline content was observed under salt treated plants as compared to the plants under control. There was significant decrease in the root length with increase in the salt concentration. On the basis of modified standard evaluation score (SES) of visual salt injury, the 22 varieties can be grouped into tolerant, moderately tolerant, susceptible and highly susceptible with most of the varieties falling under the category of moderately tolerant. Little Pink, Lalit, Haldighati and Pusa Aditya falling under the tolerant category while Himanshu and Pusa Sona are grouped under susceptible and highly susceptible category respectively.