Late-Season drought tolerance in maize and sorghum

man-in-sorghum.pngThe ability of a plant to postpone senescence under late-season drought is commonly defined as 'stay-green'.  Stay-green is correlated with enhanced crop productivity, grain quality, and lodging resistance in many crops.  Retention of green leaf tissue is known as visual stay-green, whereas functional stay-green is defined by maintenance of photosynthetically active tissue.  The goal of our research is to characterize the expression and genetic architecture of stay-green in maize and sorghum.  This knowledge will be applied to improving drought tolerance of these and other crops through marker-assisted selection and potentially transgenic approaches.

Maize exhibits substantial genetic variation for stay-green.  Joint linkage mapping has been used to identify multiple QTL for stay-green across several linkage groups with sources of stay-green alleles coming from diverse genetic backgrounds.  Comparisons between maize and sorghum for map positions of stay-green QTL indicate that two of the major loci occur in syntenous regions.  Identification and integration of stay-green genes into commercial programs provides the opportunity to sustainably enhance the productivity of maize and sorghum in drought environments.