Impact of high throughput green synthesized silver nanoparticles on agronomic traits of onion.

Onion (Allium cepa L.) which is belonging to the family Liliaceae, is one of the greatest vital crops field worldwide. In this current work, Stored, high throughput and green synthesized silver nanoparticles; AgNPs (2000 ppm) were used as an eco-friendly nano fertilizer for onion in field conditions. All state of art analysis (Uv-vis, TEM, SEM, particle size analyzer and zeta potential) were used to characterize the formed AgNPs. Twelve concentrations (from 5 to 100 ppm) of AgNPs, were applied to onion, in addition to, two commercial nano products as control; iron nanoparticles (FeNPs) and zinc nanoparticles (ZnNPs) (2000 and 2500 ppm, as recommended by the markets). All concentrations were prepared under optical conditions and were applied three times in open field in a randomized complete block design (RCBD) during both seasons 2017/2018 and 2018/2019 as foliar application for onion plants after 25, 40 and 55 days, directly after the first irrigation of the plant. To this end, the physio-biochemical parameters such as CO2 concentration, stomatal conductance and internal CO2 were calculated via steady-state porometer 11 (LICOR, LI-1600, Lincoln, NE, USA). After 120 days of growth sowing (DAS), yield components and quality were evaluated. Just after harvesting, onion was subjected to extraction using dichloromethane for further analysis. All extracts were analyzed using GC-MS under the optimum operational condition to calculate the different constituents. The obtained results designated that, foliar application using 20 ppm of AgNPs displayed the highest mean values of all morphological, yield, yield components and quality characters compared with other concentrations and also to the commercial products, that used very high doses ranged from 2000 to 2500 ppm that can lead to genotoxicity in term of mutations in future, for human health. In conclusion, AgNPs can be used as an eco-friendly nano fertilizer with a recommended dose of 20 ppm which is considered a safe dose to the environment and human health too, compared with the crazy doses of the available commercial products.