Abstract. A stay-green phenotype enhances the adaptation of sorghum to terminal drought conditions, although the underlying physiological mechanisms leading to the expression of stay-green remain unclear. Differences in tillering and leaf area at anthesis, transpiration efficiency (TE), water extraction, harvest index (HI) and yield under both terminal drought and fully-irrigated conditions were assessed in 29 introgression lines (IL) developed targeting stay-green QTLs Stg1, Stg2, Stg3, Stg4, StgA, and StgB in S35 background, and 16 IL developed targeting Stg1, Stg3, Stg4, and StgB in R16