Seasonal precipitation and soil mineral nutrients contribute to variation in ginsenoside accumulation in American ginseng across China's major production regions.

Ginsenosides are the primary bioactive constituents of American ginseng (Panax quinquefolius L.); however, the relative contributions of climatic factors and soil properties to variation in individual ginsenosides and overall ginsenoside composition across major cultivation regions remain largely unquantified. To address this gap, six major ginsenosides were quantified, including the protopanaxatriol (PPT)-type ginsenosides Rg1 and Re and the protopanaxadiol (PPD)-type ginsenosides Rb1, Rc, Rb2, and Rd, across 41 geographically distinct sites in China. Site-specific meteorological data and soil variables were integrated to quantify the contributions of environmental factors to variation in individual ginsenosides and in overall compositional profiles. Re declined significantly with increasing latitude, whereas Rb2 increased with latitude. Precipitation, particularly precipitation in January and March, emerged as key climatic explanatory variables for variation in PPT-type ginsenosides as well as Rb2. Soil exchangeable calcium (ECa) and available copper (ACu) contributed most strongly to the variation in Rc (ECa: 49.9%) and Rb1 (ACu: 36.1%), respectively. Variation in Rd was jointly explained by climatic and edaphic factors. Redundancy analysis further showed that the measured environmental variables collectively explained 46% of the spatial variation in ginsenoside compositional profiles (F = 9.5; p = 0.001). This study provides a quantitative framework for understanding the key environmental factors associated with ginsenoside composition and for guiding site-specific cultivation management.