Ex-foliar application of glycine betaine and its impact on protein, carbohydrates and induction of ROS scavenging system during drought stress in flax (Linum usitatissimum)

•Screening of mini-core collection of flax and identification of contrasting genotypes for drought tolerance.•Exfoliar GB induces osmolytes accumulation and imparts drought tolerance in flax.•Exogenous GB induces enzymatic/non-enzymatic ROS scavenging antioxidant system in flax.