COLD HARDINESS OF SOUTHERN AND NORTHERN SALTGRASS ECOTYPES
Cold hardiness is an important biological adaptation that controls plant distribution especially for a potential turfgrass. The objective of this study was to compare the cold hardiness and winter survival of saltgrass [Distichlis spicata (L.) Greene] accessions collected from southern and northern climates. Northern accessions, COAZ-01, COAZ-02, and CO-01 were collected from the Front Range of Colorado. Southern accessions, COAZ-03, COAZ-04 and COAZ-05, were collected from San Joaquin Valley, California. Plugs of these accessions were planted in the field in the summer of 2003. Rhizomes of each accession were sampled in December 2004, November 2005, January and March 2006 and subjected to laboratory freezing tests. Winter injury was evaluated in the field. Ranking of accessions for the subfreezing temperature resulting in 50% mortality (LT50) in December 2004 was CO-01 (-18°C) = COAZ-01 (-16°C) = COAZ-02 (-15°C) > COAZ-03 (-10°C) = COAZ-04 (-9°C) = COAZ-05 (-8°C). In November 2005, the lowest LT50 was -20°C achieved by COAZ-01 and COAZ-02 and the highest exhibited by COAZ-04 (-8.7°C). In January 2006 COAZ-01 achieved the lowest LT50 of -25°C. LT50 increased in March. It ranged from -10 to -22°C. LT50 data over three winters suggested that the northern accessions were 5 to 10 degrees more cold hardy than the southern accessions. During the winter of 2003-2004, the southern accessions suffered 85-92% winter injury in the field whereas the northern accessions exhibited ≤ 10% winter injury. No significant difference in field winter injury among accessions was observed in the winters of 2004-2005 or 2005-2006. In summary, southern ecotypes are less freeze tolerant than the northern ecotypes. This information is important for breeders to develop turf-type saltgrass accessions for regional use.
Shahba, M.A., Wilhelm, S.J. and Qian, Y.L. 2008. COLD HARDINESS OF SOUTHERN AND NORTHERN SALTGRASS ECOTYPES. Acta Hort. (ISHS) 783:175-181
Distichlis spicata, freezing tolerance, winter survival, turfgrass