Abstract
This work investigated the relationship between phytoliths from finger millet, pearl millet and sorghum and the water conditions under which these species grow. The archaeological debate on the use of millets remains open and finding a proxy to help recognise their growing conditions is crucial for the reconstruction of their dispersal. In this research phytolith concentration, ratio of sensitive to fixed morphotypes, phytolith assemblage composition, morphometry, and Si isotopic composition of sensitive morphotypes were analysed as potential indicators of plant water availability. The results showed changes in both the assemblage composition, the bulliform dimensions and isotopic content, depending on the species. Intra- and inter-specific differences were highlighted. In view of the results a predictive model based on morphotype concentration was elaborated and applied to four case-studies of the Indus Valley Civilization, proving that phytoliths can be efficient proxies to assess the water condition of plant growth in the archaeological record.