Effects of Water Deficiency at Different Phenological Stages on Oxidative Defense, Ionic Content, and Yield of Triticale (x Triticosecale Wittmack) Irrigated with Saline Water

The aim of this study was to better understand the individual and combined effects of water deficit (at different phenological stages) and salt stress on some morpho-physiological and biochemical traits (i.e., antioxidant enzyme activity, MDA, H2O2, and ion content) of triticale. A factorial experiment was conducted in a randomized complete block design. Experimental factors included salinity in three levels (no-salt, 50, and 100 mM NaCl) and water deficit stress in four phenological stages (regular irrigation as control, irrigation disruption at heading, flowering, and kernel extension stages). Results indicated that salinity, water deficit stress, and their combination decreased yield, plant dry weight, grain number per spike, potassium (K+) content of leaf and root, and the ratios of leaf and root K+/Na+. On the other hand, they increased malondialdehyde (MDA), hydrogen peroxide, sodium (Na+) content, and the activity of catalase (CAT), peroxidase (POD), and ascorbate peroxidase (APX) enzymes in triticale. The average effects of mild and severe salinity when they coincided with water deficit stress at the heading, flowering, and kernel extension stages reduced grain yield by 77.85, 86.06, and 73.62, respectively. It can be concluded that the flowering stage was more sensitive than the other stages to the coincidence of salinity stress and water shortage.