ASSOCIATION OF SALT TOLERANCE AT SEEDLING EMERGENCE WITH ADULT-PLANT PERFORMANCE IN SLENDER WHEATGRASS

Regrowth of 15 slender wheatgrass (SWG, Elymus trachycalus sp. trachyc alus (= Agropyron trachycaulum Link Malte) lines was evaluated after 3 (harvest-one) and 11 wk (harvest-two) after clipping at four salinity levels. Lines were previously categorized into salt-tolerant (TOL) an d non salt-tolerant (NT) accessions based on percent emergence at 15 m S cm(-1) relative to a salt-tolerant control, tall wheatgrass (TWG, Ag ropyron elongatum (Host) Beauv. [= Thinopyron ponticum (Podpera) Lu & Wong]. Regrowth of five TOL, five NT, five untested (UT) SWG lines and TWG were compared in a greenhouse with nutrient solutions salinized t o EC(e) values of 2, 7, 15, and 23 mS cm(-1). Regrowth of all SWG line s decreased from 68 to 98% as salinity increased. Orbit tall wheatgras s shoots were about threefold larger than SWG shoots at 15 and 23 mS c m(-1). Phenological development of NT lines was slower (P less than or equal to 0.05) than that of TOL and UT lines at all EC(e) levels. How ever, shoot growth of NT lines exceeded (P less than or equal to 0.05) that of TOL lines at 23 mS cm(-1). Regrowth after 3 and 11 wk were co rrelated within EC(e) levels, (r = 0.22 to r = 0.34, P less than or eq ual to 0.01). Lack of a positive relationship between lines selected f or emergence in saline media and their subsequent growth under saline conditions indicates that improvements in adult plant growth under sal ine conditions will require additional selection for appropriate trait s in SWG.