Effects of electrical conductivity and fertilizer frequency on the growth, yield and postharvest quality of Wasabi ‘Daruma’ (Eutrema japonicum) in substrate culture system

This study examined the combined effects of electrical conductivity (EC) levels and fertilizer frequency on the growth, yield, and some quality attributes of wasabi (Eutrema japonicum cv. ‘Daruma’) under controlled conditions. A nine-month factorial experiment using three EC levels (1, 2, and 3 mS cm⁻¹) and two fertilizer frequencies (weekly and biweekly) revealed significant EC × fertilizer frequency interactions. The combination of moderate EC (2 mS cm⁻¹) and weekly fertilization resulted in the highest photosynthetic rate, vigorous growth, and greatest rhizome yield, while also enhancing the 2-propenyl-glucosinolate content in rhizomes during storage. In contrast, low EC with biweekly fertilization limited growth, whereas high EC (3 mS cm⁻¹) mainly promoted petiole and leaf elongation without yield improvement. Overall, optimal EC management combined with frequent fertilization synergistically improved nutrient uptake, physiological efficiency, and storability, providing an effective strategy for high-quality wasabi production.