Accurate identification of soluble solid content in citrus by indirect laser-induced breakdown spectroscopy with its leaves

•A new approach is proposed to identify the SSC of citrus using indirect LIBS with its leaves.•By improving the GA, the problem of the local optimal solution for the recognition model is solved.•The influence of element in citrus leaves on citrus’s SSC was analyzed by ANOVA.•The indirect LIBS with citrus leaves can nondestructively and reliably identify the citrus’s SSC.