The use of cell membrane stability (CMS) technique to screen for salt tolerant wheat varieties

Cell membrane stability (CMS) technique was used to screen salt tolerant (V1, V2), salt sensitive (V5) and two salt/water deficiency tolerant wheat genotypes (V3 and V4) using 100-250 mM NaCl salinity maintained in pots containing gravel and nutrient solution. The objectives were to study: (i) the reliability of CMS technique for screening wheat under high salinity, (ii) factors that impart stability and/or injury to the cell membrane, and (iii) the relationship of CMS with other physiological parameters affected by the salt stress. Generally, cellular injury increased with increasing salinity levels. In V5, it was the highest (74.2%) at 250 mM, probably due to combined effect of Na+ toxicity and low (54%) relative water content (RWC). In V1, RWC was similar to that in V5 but injury was comparatively low possibly due to low concentration of Na+. The difference between V1 and V2 was significant, either due to the highest concentration of K+ or the lowest reduction in RWC in V2. In V3 and V4, injury was the lowest at all salinity levels and was within the range of values observed earlier for drought tolerance. A significant negative correlation was detected between cellular injury and RWC for V1 and V5 but not for V3 and V4. Cellular injury also showed a significant positive correlation with Na+ and a negative correlation with K+ and grain yield (GY). It appeared that CMS technique is suitable for screening wheat under high salinity levels and for detecting differences that may arise due to cumulative effects of salinity and reduced water contents.