Two-year field study demonstrates that combined foliar nano-zinc and nano-boron boosts grain yield under drought stress in wheat, suggesting a viable nutrient strategy for arid regions.
Key Points
To assess the effects of foliar-applied nano-zinc oxide and nano-boric acid on the physiological traits and grain yield of wheat subjected to drought stress during stem elongation.
Conducted a two-year field experiment using a split-plot factorial design with wheat (Triticum aestivum L. cv. 'Bahooth 22').
Applied drought stress during the stem elongation stage in main plots, with foliar treatments (control, nano-zinc oxide, nano-boric acid, and combined) evaluated in subplots.
Combined application of nano-zinc and nano-boron increased grain yield under water-limited conditions by approximately 42% compared to untreated controls (from 1563 to >2200 kg ha⁻¹).
Yield increases were driven by spike characteristics, specifically longer spikes and higher grain counts per spike, with no notable effect on 1000-grain weight.
Nano-zinc application maintained total chlorophyll content, preserving wheat photosynthetic capacity under drought stress.