Growth traits associated with drought survival, recovery and persistence of cocksfoot (Dactylis glomerata) under prolonged drought treatments

The effect of prolonged drought treatments on persistence, growth traits, drought survival and post-drought recovery was investigated in two sets of differently managed genotypes of cocksfoot (Dactylis glomerata L.). In total, 72 genotypes (two sets of 36 managed for seed and forage harvest, respectively) were evaluated for agro-morphological traits in the field during 2013–15 under normal and deficit irrigation regimes. In the fourth year (2016), irrigation was withheld in both irrigation treatments for 2 months and then plants were re-watered to investigate the effect of prolonged drought regimes on traits related to post-drought recovery. The deficit irrigation regime decreased persistence and recovery. These reductions were lower in the seed-management than the forage set, which indicates that delaying the first harvest of the seed-management treatment to maximise seed production led to lower impact of drought stress. The seed-management treatment also had lower persistence. The forage-management treatment had higher recovery under normal irrigation, whereas under deficit irrigation, the seed-management treatment had higher recovery. Association analysis showed the possibility of selecting genotypes having high values of persistence and drought tolerance. Results also showed a negative correlation between days to flowering and recovery after drought, indicating that selection for earliness may improve survivability and persistence of these plants. Superior genotypes with higher forage production and better recovery, persistence and drought tolerance may be recommended for development of synthetic cultivars.