PHYSIOLOGICAL CHARACTERIZATION OF WHEAT (Triticum aestivum L.) GENOTYPES UNDER SALINITY

Salinity is an abiotic stress affecting the growth and development of plants like wheat and genotypes of wheat differ in their response to salinity. These genotypic variations in wheat for salinity tolerance are due to physiological and biochemical differences. The objective of this study was to assess the genotypic differences between two wheat genotypes 25-SAWSN-12 and 25-SAWSN-8. A hydroponic study with four replications was carried out; two treatments control and salinity (125 mM NaCl) were applied. Salinity reduced shoot and root growth, a reduction in water relations, photosynthetic attributes and membrane stability index (MSI) was also observed in both genotypes but this reduction was more conspicuous in 25- SAWSN-8 than in 25-SAWSN-12. The ionic composition showed that 25-SAWSN-12 had more K^+, and less Na^+ and Clconcentrations in its shoot and root while 25-SAWSN-8 behaved in an opposite way. It seems that the reduction in growth, water relations, photosynthetic attributes and membrane stability was due to the toxic effect of Na+ and less uptake of K^+ caused by salt stress. The genotype 25-SAWSN-12 was able to cope with drastic effects of Na^+ therefore it showed better growth under salinity as compared to 25-SAWSN-8.