Association of salt tolerance at seedling emergence with adult plant performance in slender wheatgrass

Abstract

Regrowth of 15 slender wheatgrass (SWG, Elymus trachycalus sp. Trachycalus (= 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) and non salt-tolerant (NT) accessions based on percent emergence at 15 mS cm−1 relative to a salt-tolerant control, tall wheatgrass (TWG, Agropyron 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 to ECe values of 2, 7, 15, and 23 mS cm−1. Regrowth of all SWG lines decreased from 68 to 98% as salinity increased. Orbit tall wheatgrass shoots were about threefold larger than SWG shoots at 15 and 23 mS cm−1. Phenological development of NT lines was slower (P ≤ 0.05) than that of TOL and UT lines at all ECe levels. However, shoot growth of NT lines exceeded (P ≤ 0.05) that of TOL lines at 23 mS cm−1. Regrowth after 3 and 11 wk were correlated within ECe levels, (r = 0.22 to r = 0.34, P ≤ 0.01). Lack of a positive relationship between lines selected for emergence in saline media and their subsequent growth under saline conditions indicates that improvements in adult plant growth under saline conditions will require additional selection for appropriate traits in SWG. Key words: Slender wheatgrass, Elymus trachycalus sp. trachycalus (= Agropyron trachycaulum Link Malte), tall wheatgrass, Agropyron elongatum (Host) Beauv. (= Thinopyron ponticum (Podpera) Lu & Wong), salt tolerance, genetic screening, emergence