Effect of salt stress by “onsen” water on plant growth and fruit quality of tomato cv. Reika in pot soil

Salt stress often can enhance fruit quality of tomatoes. Seawater is one of the substrates used by growers. However, utilization of seawater on tomato production is difficult in the hinterland as it is far away from the seaside. Some “onsen” water also show high salt concentration (2%). Therefore, it could be also used as a substrate of salt stress treatment. In this study, salt stress was provided by Yupoka “onsen” water, and the effects of different nutrient ECs on plant growth and fruit quality of tomatoes were investigated.  Tomato plants ‘Reika’ were grown in pot soil, and nutrients with EC 2, 4, 8 and 12 mS/cm were applied at the time of irrigation. The fruits were harvested at turning stage until the 3rd truss. Soil salinity attained EC 3.6, 6.7, 12.8, and 15.6 mS/cm. SSC, organic acid, dry matter and NO3-increased by 50, 79, 50 and 27%, respectively at EC12 mS/cm while, weight, size, and water content decreased up to 40, 20, and 4%, respectively. However, fruit cracking did not occur apparently. Most of the plant growth parameters were reduced.