Screening Various Perennial Ryegrass Cultivars for Salinity Stress Tolerance.

Various ryegrass (Lolium perenne L.) cultivars (TX17, TX18, TX20, TX21, TX22,  TX23,  TX24,  TX25,  TX26,  TX28, and TX29) were screened for salinity stress tolerance. The experiment was conducted hydroponically in a greenhouse, using a RCB design trial with 4 replications. The grasses were screened by evaluating their growth responses in terms of shoot and root lengths, shoot (clippings) fresh and DM weights, and grass general quality under various sodium chloride salinity stress conditions. Treatments included NaCl at EC of 0-18 dSm^-1. Salinity level of the culture solutions were raised 2 dSm^-1 every week. Shoot and root lengths, clippings fresh and DM weights were determined weekly. After the fresh weight determinations, clippings were oven-dried at 65º C and DM weights recorded. At the last harvest, roots were also harvested and fresh weights were determined, then oven-dried at 65º C and DM weights were recorded. Grass general quality was weekly evaluated. The results showed shoot and root lengths and clippings fresh and DM weights of all the cultivars decreased as salinity level of the culture solution increased. Grass general quality followed the same pattern as the shoot lengths, clippings fresh and DM weights. General quality of all the cultivars decreased as the salinity level increased. Significant differences were detected in the studied parameters among the various cultivars. Therefore, the cultivars were divided in several distinct groups from high to low degrees of salinity stress tolerance. Based on the results of this study, the TX24 and TX28 were the most tolerant cultivars to salinity stress, followed by TX17 and TX23. The TX20, TX21, TX22, and TX26 cultivars were in the 3^rd group. Three cultivars (TX18, TX25, and TX29) fell in the 4^th group, the least tolerant cultivars to NaCl salinity stress.