Cold Tolerance Evaluation of Several Centipedegrass Selections 1

Centipedegrass ( Eremochloa ophiuroides (Munro) Hack.), an excellent lawn grass throughout much of the lower South, is often limited by its lack of cold tolerance. Studies were conducted to determine variability in cold tolerance among centipedegrass selections as affected by hardening conditions. Seven clonal selections were grown under controlled environmental conditions using sand culture and cold hardened during a 21‐day exposure with a 12‐hour photoperiod, 22 C day (16 C day in the second experiment), 4 C night. Unhardened plants recieved a 31 C day, 25 C night. In one experiment, following hardening treatments, plants were exposed to —9.7 C for 1.5, 3, 5, 7 or 9 hours. In a second experiment plants were exposed to —3.0, —5.6, —7.3, or —10.1 C for 4 hours. After low‐temperature exposure plants were transferred to favorable growing conditions and rated for top‐kill and survival after 7 and 21 days respectively. Top‐kill increased and survival decreased as duration of cold exposure increased or temperature decreased. Exposing centipedegrass to cold hardening temperature regimes prior to freezing resulted in less top‐kill and more survival. Cold hardening increased low‐temperature tolerance a maximum of 2.3 C; i.e., percent survival was the same for hardened plants at —9.6 C as for unhardened plants at —7.3 C. Selections differed in amounts of top‐kill. Mississippi I, Tennessee Hardy, Oklawn, and FC‐2 were generally less susceptible to top‐kill than PllA,, Mississippi II, and FC‐8. No survival differences were noted among Centipedegrass selections following low‐temperature exposures.