Differential physio-biochemical, mineral content, and fruit quality responses to water salinity in date palm (Phoenix dactylifera L.) varieties

Date palm ( Phoenix dactylifera L.) is a valuable crop with nutritional and economic significance. This study evaluated the effects of 03 water salinities (5, 10, and 15 dS m⁻¹) on fruit quality traits in 17 varieties (10 from the UAE, 7 from Saudi Arabia) over eight seasons (2007–2011, 2013–2015). Measured traits included fruit weight, length, width, volume, and seed weight. Under low salinity, fruit length (8 -14%), width 2–3 cm, volume 9.3–18.8 cm³, weight 8.4–19.2 g, and seed weight 0.7–1.8 g. High salinity (15 dS m⁻¹) reduced fruit length by 8.7%, volume by 22.2%, weight by 11.2%, and width by 7.5%, with wide varietal variation. Khisab, Sukkari, Rothan, and Jabri showed the least reduction (5.7–9.4%), while Lulu, Barhi, Um Alhamam, and Naghal showed the highest (17.6–23.4%). Mineral concentrations varied by variety and salinity level, with inconsistent trends. Sodium accumulation negatively correlated with fruit yield. High-yielding varieties such as Lulu, Barhi, and Naghal maintained overall productivity by increasing bunch and fruit number despite reduced individual fruit quality, in contrast to varieties with stable fruit traits, which showed greater sensitivity to salinity. These findings provide a scientific basis for the selection of salinity-tolerant date palm cultivars and the optimization of irrigation strategies, thereby contributing to more sustainable and resilient date palm production under saline conditions. • Seventeen date palm varieties tested under 5, 10, and 15 dS/m salinity. • High salinity (15 dS/m) reduced fruit traits; fruit length dropped by 87.5%. • Khisab, Sukkari, Rothan, and Jabri had least reduction in fruit traits. • Mineral levels varied by cultivar and salinity, with inconsistent effects. • Higher sodium showed negative correlation with fruit yield in most cultivars.