This document discusses genetic manipulation of stay-green traits for crop improvement. It defines stay-green as extended foliar greenness during grain filling under drought. Stay-green is important for maintaining photosynthesis and yield under drought. Strategies for developing stay-green crops include identifying QTL for the trait and using marker-assisted breeding to introgress those QTL into preferred crop varieties. Maintaining chlorophyll levels through delayed senescence is key to stay-green. Introgressing stay-green traits can increase drought resistance and yield potential of important crops.