Survival and recovery of tall fescue genotypes: association with root characteristics and drought tolerance

Abstract

Identification and selection of plant genotypes with survival, recovery and sustainable performance during drought periods is one of the main objectives of plant improvement for arid and semi-arid regions. This study aimed to evaluate root traits and recovery of tall fescue genotypes after a period of drought stress. A total of twenty four tall fescue genotypes were selected from a wide polycross population and assessed for field drought tolerance based on stress tolerance index (STI) and recovery during 2010-2013. The genotypes were classified as tolerant, moderately tolerant and susceptible based on STI. Then, in 2014, genotypes were assessed in a pot experiment for root characteristics under two levels of moisture environments (control and intense drought stress). In both moisture environments, root length (RL), root area (RA), root volume (RV) and root weight (RW) were negatively correlated with days to recovery (DR). Genotypes that recovered from drought had greater RL, RA, RV and RW than the genotypes unable to recover. Principle component analysis (PCA) was performed to identify genotypes with superior root characteristics, stress tolerance and recovery potential that can be used for future breeding programmes. Results indicated that selection based on combining STI, recovery and extensive root system might improve drought tolerance of tall fescue.

Variation in persistency, postdrought recovery and root characteristics in a tall fescue germplasm under interactive effects of exogenously applied salicylic acid and water stress

“…Festuca arundinacea Schreb.) genotypes (Table S1) were selected from our previous materials based on productivity related traits according to the results of previous studies (Majidi et al., 2009; Pirnajmedin et al., 2016). The genotypes were clonally propagated in a greenhouse and then transferred to the field in March 2015.…”

“…Pirnajmedin et al. (2016) reported that selection based on combining a stress tolerance index (STI), recovery and an extensive root system might improve the drought tolerance of tall fescue.…”

“…Because of access limitations, less attention has been given to roots compared to more easily assessable aboveground traits (Lilley & Kirkegaard, 2011). Positive correlations between drought tolerance index and certain root traits such as root length (RL), root volume (RV) and PE have been reported (Abtahi et al., 2017; Pirnajmedin et al., 2016). RL and root to shoot ratio were regarded as reliable criteria for selecting drought stress‐tolerant and persistent genotypes of turfgrass in semi‐arid and arid regions (Karcher et al., 2008).…”

Nonlinear drought plasticity reveals intraspecific diversity in a dominant grass species

“…Like phenotypes and plasticity, recovery ability differs among genotypes in other grasses (e.g. Cui et al., 2015; Hawkes & Kiniry, 2018; Pirnajmedin et al., 2016), but comparisons are rarely made among coexisting genotypes of a single population, and may not reflect strategies occurring in local‐scale communities versus among populations. For example, Andropogon gerardii genotypes differ in recovery of gene expression and physiology following re‐watering (Avolio et al., 2018; Avolio & Smith, 2013b), but it is unclear if these findings apply to productivity and growth‐related phenotypes.…”

Root characteristic system improves drought tolerance in orchardgrass

“…() found that water stress reduced root biomass, specific root length (RL), root tissue density and root dry matter content and increased root diameter in some forage grasses. In tall fescue ( Festuca arundinacea ), significant reduction in RL, root area (RA), root volume, root weight and root dry matter percentage is reported under water stress conditions (Pirnajmedin, Majidi, & Gheysari, , ). Wang and Bughrara () reported that drought stress significantly reduced root biomass and RL of several forage grasses.…”