Salt tolerance of five varieties of tall fescue at the germination stage

The top of paper (TP) germination method was used to compare the salt tolerance for five tall fescue (Festuca arundinacea) strains at the germination stage in an illumination incubator. Double-layered paper moistened with pure distilled water served as the control, whereas the papers for the experiment were moistened with 6 NaCl concentrations respectively: 50, 100, 150, 200 and 250 mmol·L^–1. Germination potential, rate, and index, shoot and root length, as well as salt damage rate showed no remarkable difference between the control (P > 0.05) and the strain germinating at 50 mmol·L^–1 NaCl. Relative germination potential, percentage, and index, shoot and root length, and seed vigor index decreased with increases in NaCl concentration; however, the relative salt damage increased when the NaCl stress increased from 50 to 250 mmol·L^–1. At 250 mmol·L^–1 NaCl, the seedings were seriously damaged, and the relative germination potential, percentage, and index, shoot and root length, and seed vigor index were at their lowest (P < 0.05). The results following comprehensive assessment indicate that the 5 strains can be arranged as follows in the decreasing order of salt tolerance: Tar Heel Ⅵ > Watchdog > RubyⅡ > Baker > Super Watchdog.