333 The Korean Society of Crop Science J. Crop Sci. Biotech. 2015 (December) 18 (5) : 333 ~ 340 RESEARCH ARTICLE DOI No. 10.1007/s12892-015-0064-2 Evaluation of Wheat Genotypes for Salt Tolerance Based on Some Physiological Traits Abu Hasan 1* , Hafizur Rahman Hafiz 1 , Nurealam Siddiqui 2 , M. Khatun 1 , Rabiul Islam 1 , Abdullah -Al Mamun 3 1 Department of Crop Physiology and Ecology, Hajee Mohammad Danesh Science and Technology University, Dinajpur-5200, Bangladesh 2 Department of Biochemistry and Molecular Biology, Bangabandhu Sheikh Mujibur Rahman Agricultural University, Gazipur-1706, Bangladesh 3 Department of Agronomy, Bangabandhu Sheikh Mujibur Rahman Agricultural University, Gazipur-1706, Bangladesh Received: June 25, 2015 / Revised: August 9, 2015 /Accepted: August 12, 2015 Ⓒ Korean Society of Crop Science and Springer 2015 Abstract Identification of physiological markers related with salt tolerance during various vegetative and reproductive stages is cru- cial for evaluating wheat genotypes and improving their salt tolerance. Two salt-tolerant (Shatabdi and BAW 1135) and two salt-sensitive (BARI Gom 26 and BAW 1122) wheat genotypes of Bangladesh were grown in three salinity levels (control, 6 dS m -1 , and 12 dS m -1 ) to observe the sensitivity of some physiological traits.. Salt-tolerant wheat genotypes maintained lower levels of leaf Na, higher levels of leaf K, and greater K/Na ratios in saline conditions than the sensitive one. Due to salt stress, flag leaf proline content was increased in salt-tolerant wheat genotypes whereas the proline level was decreased in the sensi- tive one compared to the control. Salt-sensitive genotypes showed a greater increment in SPAD (relative chlorophyll content) value at moderate salt stress but a greater reduction in SPAD values at high salt stress than tolerant ones. Salt-sensitive geno- types were affected more in their straw yield and finally grain yield plants -1 under saline conditions than salt-tolerant geno- types. There was a highly significant negative correlation between grain yield and Na content and also a highly significant negative correlation between grain yield and K : Na content of the wheat genotypes under saline environments. We also observed stress susceptibility index (SSI) based on grain yield plant -1 the order of tolerance was BAW 1135 > Shatabdi > BARI Gom 26 > BAW 1122 at moderate salinity level and BAW 1135 > Shatabdi > BAW 1122 > BARI Gom 26 at high salinity. Key words : salinity, K/Na, SPAD value, proline content, wheat, yield Abbreviations SSI: Salt susceptibility index, Na: Sodium, K: Potassium, Mha: Metric hectare, Cl: Chloride Among various environmental stresses, soil salinity has become a critical problem worldwide due to its dramatic effects on plant physiology and performances, and affects about 7% of the world’s total land area (Flowers et al. 1997). Over 400 Mha of land across the world are affected by salini- ty that is about 25% of the world’s total area including 950,780 ha of Bangladesh’s lands (Ghassemi et al. 1995). Salinity delays the onset, reduces the rate, and increases the dispersion of germination events, resulting in reduced plant growth and final crop yield (Ashraf and Foolad 2005). Soil salinity may affect the germination of seeds either by creating osmotic potential external to the seeds preventing water uptake or through the toxic effects of Na + and Cl - ions on germinating seed (Khajeh-Hosseini et al. 2003). Salinity changes the morphology, physiology, and metabolism of plants (Rhoades 1993), ultimately diminishing growth and yield (Ashraf and Harris 2004). Grain yield is frequently Introduction Abu Hasan ( ) Email: mdabuhasan @yahoo.com