Purpose The role of protecting and structure-stabilizing silicon (Si) has been demonstrated on different plant species. However, it has not been used in potato seed production under a soilless culture system. Therefore, this experiment was conducted to evaluate the ionized –Si and nano-Si particles on physiological characteristics and yield of potato mini-tuber. Methods A greenhouse experiment under a soilless culture system was performed as a randomized complete block design (RCBD) arranged in factorial with three replications. In this study, Si concentration (distilled water (Control), 0.8, 1.6, 2.4, and 3.2 mmol Si L⁻¹) and Si type at two levels (nano and ionized Si-based in sodium silicate) were tested. Results The results revealed that foliar application of Si significantly improved the net photosynthesis rate, water use efficiency, mesophyll conductance, Chl a, Chl b, carotenoids, Chl a/b ratio, DPPH radical scavenging, total phenol, shoot dry weight, Si concentration in shoot, mean weight mini-tuber, and yield, whereas transpiration rate in Si-treated plants decreased. Moreover, the highest positive influence of Si was observed at 3.2 mmol L⁻¹. The effect of nano-Si was higher than ionized-Si at all Si concentrations. The results revealed improved physiological characteristics and yield of potato plantlets under nano-Si treatments compared to ionized-Si treatments. However, these relations were not significant under ionized treatment. Conclusions This study indicated that the application of Si (nano and ionized) for potato growing and mini-tuber production has positive effects. Generally, under a soilless culture system, Nano-Si has higher efficiency than ionized-Si in mini-tuber production.

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