Genotypic‐specific response to exogenous applied salicylic acid in tall fescue under different irrigation conditions

Abstract

AbstractSalicylic acid (SA) is one of the endogenous plant growth regulators that play an important role in the regulation of plant growth and development in response to water deficit. Genotypic‐specific response to exogenous applied SA in terms of physiological, enzymatic activity, and yield traits is poorly understood in tall fescue [Lolium arundinaceum (Schreb.) Wimm. syn. Festuca arundinacea Schreb.]. Twenty genotypes of tall fescue (selected from a broad germplasm) were assessed at field condition for morphological and physiological characteristics during 2016 and 2017 under three irrigation levels (normal, mild, and intense drought stress) in the presence of two SA concentrations (0 and 1 mM). Mild and intense drought stress conditions led to depression in photosynthetic pigments including chlorophyll a and b and total chlorophyll contents, plant height, crown diameter, and forage yield, despite increases in proline content, carotenoids, catalase, peroxidase, and ascorbate peroxidase activities. Application of SA decreased the adverse effects of drought stress by elevation of photosynthetic pigments and nonenzyme and enzymatic antioxidant activities and could enhance forage yield and drought tolerance in tall fescue genotypes. High genetic variation was observed among the genotypes in their response to the application of SA under drought stress conditions, and genotypes 3L and 1E were recognized as drought tolerant and stable genotypes for future breeding programs.