Does basin wildrye (Leymus cinereus) show local adaptation when deployed according to generalized provisional seed zones in the Central Basin and Range ecoregion?

Abstract

Identifying genetically appropriate plant materials for seed-based restoration relies on the principle of local adaptation: the intent to match adaptive genetic characteristics to variation in ecological clines pertinent to plant establishment and persistence. Seed zone maps delineate some of these relationships. Generalized provisional seed zones (GPSZ) were developed for use where species-specific seed zones are lacking, as was the case for basin wildrye at the initiation of this study. In this study, basin wildrye (Leymus cinereus (Scribn. & Merr.) Á. Löve [Poaceae]) sources from 25 wild populations and 4 commercial varieties were planted at 4 test sites representing the species distribution across GPSZ in the central basin and range ecoregion. Sources were seeded separately into 5 blocks for each of 2 treatments and data were grouped by tetraploid or octoploid cytotype and local or non-local origin for comparison. Treatments included coverage with row cover or uncovered controls. We assessed initial and short-term survival. Plantings failed at 2 sites in both 2013 and 2014, with too few plants to quantify differences. At the remaining 2 sites we found no differences in initial survival or short-term persistence between pooled local sources compared to pooled non-local sources. Among commercial sources, the cultivar ‘Magnar’ initially outperformed local pooled materials at Fountain Green but not at Nephi. This difference was not evident 3 and 4 y later. Initial establishment under row cover was dramatically better than uncovered controls but persisted only through years 3 and 4 at the Fountain Green site.