Effect of Nano-Zinc Chelate and Phosphorus on the Physiological Response of Some Maize hybrids

Maize is a strategic commodity because of its high productivity and diverse uses. To investigate the impact of different levels of nano-zinc chelate and phosphorus fertilizer on the growth and yield of maize hybrids. Field experiments were conducted at the Qlyasan Agriculture Research Station in Sulaymaniyah, Iraq. The treatments included three maize hybrids (G1, G2, and G3), three levels of nano-zinc fertilizer 10 and 20 mg L^-1, and three levels of phosphorus 100 and 200 kg h^-1. The randomized complete block design evaluated growth, chemical, and yield parameters. In both experiments, the G3 surpassed both genotypes in kernel yield, 14.410 and 13.522 tons ha^-1, respectively.  Concerning nano-Zn chelate, control and 20 mg L^-1 gave maximum kernel yield with 19.323 tons ha^-1 for both experiments. An increase in oil in both experiments was associated with G2 (3.885% and 4.002%, respectively). Protein gave a maximum value of 6.977% for G3 in the P fertilizer. The 10 mg L^-1 zinc gave the highest oil (5.748%). Control recorded a maximum protein content of 10.328 % in the 1^st experiment.  In contrast, 100 kg ha^-1 phosphorus recorded a maximum value of 10.353 in the 2^nd experiment. Both experiments’ G2 and the highest fertilization level gave a maximum oil 3.940% and 4.255%, respectively. The highest protein was associated with the interaction between G3× 20 mg L^-1 nano-zinc chelate, while the interaction between G1×100 kg ha^-1 phosphorus gave the highest protein content. The study demonstrated that maize hybrid G3 generally outperformed the others in kernel yield and protein content, while G2 showed higher oil content across both experiments. Nano-zinc chelate and phosphorus application influenced various physiological traits, though the control treatments unexpectedly yielded the highest kernel production, suggesting possible over-fertilization effects or genotype-specific nutrient responses.