Authenticating the geographical origin of the Chinese yam (Tiegun) with stable isotopes and multiple elements

•SIRs and multi-elements characters of Chinese yam (Tiegun) from 7 geo-origins were described.•Chinese yam (Tiegun) from different producing areas were accurately authenticated.•22 elements and δ15N were selected as key variables from 44 elements and 4 SIRs.•6 environmental factors were found to be important in explaining the variance of above variables.