In Vitro Screening of Tall Fescue (Festuca arundinacea) for Salinity Tolerance.

California’s Central Valley has experienced a significant population increase over the past several decades, and a subsequent increase in acreage planted with turfgrasses. The recent drought conditions and resulting water restrictions have renewed interest in water use in the urban landscape, especially this turf component. With the availability of potable water becoming increasingly limited, the use of recycled water is becoming more commonplace.  Unfortunately, little data exists for modern turfgrass varieties’ tolerance to the often higher salinity of such water. The project conducted here utilized an in vitro selection-based approach first described by Torrello and Symington in 1984.  However, the varieties screened in this early work are no longer in use. To this end, ten varieties of currently used Tall Fescue [Shenandoah Elite (RK 6),Firecracker LS (MVS-MST), Faith (K06-WA), SC-1, Raptor 2, Van Gogh, Fat Cat (IS-TF-161), WolfPack II (PST-5WMB), Falcon V (ATM), and Spyder LS (Z-2000)] were selected based on their use in California’s Central Valley and performance data (drought tolerance etc.) as determined by the National Turfgrass Evaluation Program (NTEP) trials of 2008. These varieties ranged from highly drought tolerant to drought susceptible, and all received the highest turf grass quality ratings, indicating their likely continued use in this region. This project involved the application of a selection pressure (NaCl) at increasing concentrations (0.0, 17, 43, 85 or 170 mM) similar to that found in saline irrigation waters.  Use of in vitro culture allowed for germination rate and percentage of large numbers of seed to be assayed in a controlled environment.  In addition, somaclonal variation that often occurs within in vitro callus cultures were utilized to screen for salt-tolerant cell lines as demonstrated by Winicov in 1991.