Temperature Effects on the Yield and Quality of the Medicinal Plant Pinellia ternata Breit

Crude drugs have been effectively included as part of Japanese medicine since ancient times. However, modern Kampo medicine in Japan mostly depends upon the import of drugs from China. In recent years, Japanese Kampo manufacturers have suffered from the rapid increase in export prices of Chinese drugs (Yamaoka et al., 2017). Many of the medicinal resources in herb medicine remain largely untapped. The domestication of medicinal wild plants and preservation of their ecological systems are required to achieve a stable supply of herb medicines in Japan. The medicinal plant Pinellia ternata Breit., which is a non-domesticated plant, is widely distributed in Japan (from Hokkaido to the Ryukyu islands). However, the drug made from P. ternata is not currently produced in Japan. The P. ternata drug is made from the corm and has an antiemetic effect: the major effective ingredient is a watersoluble polysaccharide mainly consisting of arabinose (Maki et al., 1987). Therefore, we aimed to domesticate P. ternata and select favorable lines as medicinal material. Here, we investigated the air temperature effects on the plant growth and the effective ingredient content.