Effect of Salt Stress on Growth and Chlorophyll Content of Some Cultivated Cotton Varieties Grown in Syria

Five upland cotton varieties (Gossypium hirsutum L.) (Aleppo 118, Aleppo 33/1, Aleppo 90, Raqqa 5, and Deir-Ezzor 22) were evaluated under different salinity indices [0, 50, 100, and 200 mM sodium chloride (NaCl)] for 56 days. During the course of the experiment, plant size (HT), leaf number (LN) and leaf area (LA), chlorophyll SPAD (Soil Plant Analyses Development), chlorophyll (Chl) a and b content, and osmotic potential were measured in both control and salt-stressed plants for all tested varieties. Salt-stress application reduced the HT and LN of all varieties, whereas LA decreased as salinity level increased for all tested varieties comapared to their respective control expect for Deir-Ezzor 22 variety. Our data showed that LA, Chl a and b, and chlorophyll SPAD can be used to discriminate between salt-tolerant varieties and salt-sensitive ones. In this respect, Deir-Ezzor 22 variety differed by showing high salt tolerance relative to Aleppo 118 and Aleppo 33/1 varieties. Therefore, this investigation aimed for a better understanding of the different responses presented among these varieties toward salt treatment.