Genotype-specific grafting of tomato under saline water irrigation: conferring physiological adaptation, ion homeostasis, antioxidant activity and yield

• Grafting enhanced tomato stress tolerance and adaptation to saline irrigation. • Maxifort rootstock outperformed Areenez, Pimp and control plant at 10 dS m -1 salinity. • Maxifort enhanced antioxidants (SOD, APX, POD, CAT, PPO) and K + /Na + ratio (39.50 %). • Maxifort reduced MDA (21 %) and increased fruit yield (27.96 %) than control plants. • Self-grafting showed moderate resilience in yield and fruit quality under salt stress. Continuous irrigation with saline water causes osmotic stress and ion toxicity, thereby extremely hindering tomato cultivation in dry areas where fresh water resources are scarce for regular irrigation. The experiment includes three tomato rootstock genotypes namely Areenez (G A ), Maxifort (G M ) and Pimp (G P ). Areenez is a commercial variety, which also used as scion for self-grafting and control (non-grafted plants, G N ), thus to compare with interspecific grafting to confer salt tolerance. The tomato plants were irrigated with- tap water (control, SI 0 ), 5 dSm -1 (SI 5 ) and 10 dSm -1 (SI 10 ) concentrations of saline water in a net house on the roof. The main block was the saline water treatments, and grafting rootstocks were allocated in the sub block based on the split plot design. Maxifort rootstock substantially improved pigments on leaves (Chl a 1.08 mg g -1 FW, Chl b 0.77 mg g -1 FW), antioxidant activity (SOD 31.70 %, APX 35.42 %, POD 51.02 %, CAT 16.03 %) and fruit yield where the increase was 27.96 % under SI 10 levels of saline water as compared to non-grafted plants. It also demonstrated a consistently 23.90 % lower Na + uptake, 39.50 % higher K + /Na + , 21 % lower lipid peroxidation, and 67.38 % membrane stability. Grafting onto Maxifort was superior to the other grafting combinations on flowering (55.06 plant -1 ) and fruiting (15.62 plant -1 ) with saline water irrigation, but the self-grafted plants were moderately resilient in a variety of characteristics. So, this research findings justify Maxifort as a promising rootstock in production of tomatoes in arid areas with limited availability of fresh water. Nevertheless, the molecular mechanism behind the superior root functions of the graft combination, and the long-term agronomic and economic feasibility under varying climatic conditions should be studied in future.