Abstract
Climate change models predict more frequent and severe droughts in the world. For the future adaptation of perennial forage grasses, identification and selection of genotypes with enhanced recovery and persistence under repeated drought is crucial. The aim of the present study was to investigate traits related to persistence, recovery, and root adaptation in three sets of tall fescue genotypes with different flowering date, after successive drought stress. A total of 72 genotypes of tall fescue (24 medium, 24 late, 24 early flowering) were assessed for agro-morphological traits and persistence during 2010-2014 under two levels of soil moisture. In 2015, irrigation was withheld and all genotypes were evaluated for drought recovery in the field. Then 18 genotypes were chosen based on field results to evaluate their root traits at two irrigation levels (control and intense drought stress) in pots. In the field, plant persistence decreased from year 2 to 5 under both control and intense drought stress conditions in all three sets of genotypes, although persistence of late flowering genotypes was higher. The results also indicated that most of the genotypes with greatest persistence had higher recovery after the final severe drought. Persistence and recovery were positively correlated with root length (RL), root area (RA), root volume (RV), root weight (RW) and root to shoot ratio (R/S) under both soil moisture. Moreover, genotypes with higher recovery after drought had more RL, RA, RV and R/S than others. Application of principle component analysis to identify genotypes of interest for future breeding programs is discussed.