Response of grain ‎yield, and grain Zn and P content of wheat to seed-priming with Zn under different P ‎fertilizer rate application

 Priming seed with nutrients may improve crop growth and yield. Nutrient seed priming is an easy, efficient, potential technique adopted widely by farmers and researchers to improve seedling growth, standing establishment and grain yield as well as quality of crop plants. The present study aimed to investigate the efficacy of Zn-seed priming and P application on Zn and P content in ‎grains of a winter wheat under rain-fed condition.‎

The present study consisted of two main treatments: seed priming (Hydro priming and seed priming with Zn) and P fertilizer level (0, 20, 40 and 60 kg P ha-1). The experiment was a 2×4 factorial combination of priming and P fertilizer. Experiment carried out in a randomized complete block design with three replications. Yield and yield components and nutrient (Zn and P) concentration in seeds were evaluated in response to Zn-priming and P fertilizer. Field experiment conducted under dryland farming during wheat growing season (2021-2022) in Ilam province. Seeds were primed with water (hydro-priming) or 0.3% (W/V) ‎ZnSO4.7H2O solution (Zn-seed priming) for 10 h. P fertilizer was applied to the soil before seed sowing. Control treatment received no P application.

Seed priming with ZnSO4.7H2O solution for 10 hours resulted in a significant increase in total zinc content of primed seeds compared to non primed group. Priming seeds for 10 h significantly increased (16-fold) primed Zn content in seeds as compared to hydro-primed seeds. Seeds priming and P fertilizer had a significant effect on grain yield of the wheat cultivar (Rijaw) tested in the present study. The number of spike plant-1 was not significantly affected by Zn-priming treatment. Priming seeds with Zn significantly enhanced thousand-grain weight. Seed number per spike was also significantly affected by Zn priming treatment. Plant grown from Zn-primed seeds exhibited higher number of seed per spike. Harvest index was significantly affected by Zn priming. Zn-primed plants showed higher harvest index than control plants. Yield components were also affected by dose of P fertilizer application. Grain weights, seed number per spike and harvest index were increased due to applied P fertilizer. P application of 60 kg per ha was the best in terms of enhanced seed weight, seed number per spike and harvest index. However, spike number was not significantly affected by P application rate. Result of the present study showed a significant interaction between Z priming and P application for seed number per spike, grain yield as well as Zn and P content in seeds. Application of 60 kg P ha-1 resulted in increase in seed P content and grain yield. Application of P fertilizer, especially at the highest rate (60 kg ha-1), significantly reduced Zn concentration in grains. The maximum grain yield was achieved by application of 60 kg P ha-1 and Zn-seed priming. Plants grown from Zn-primed seeds had lower P content in grain. Results showed that applied Zn via seed priming increased Zn content in grain.

Results of the present study showed that the benefit effects of priming with Zn depend on the P application rate. P application at higher rate significantly reduced Zn content in grain and increase P concentration in seeds. Zn priming has a promoted effect on elevation Zn content in wheat cultivars. However, applied P, especially at the highest rate, decreased Zn concentration in seeds.