You probably should reckon that even the term 'drought' requires some further detail about temperature soil capacity, salinity, stress duration and season, as well the fact that from a large set of QTL there would be more tha 1000 possible molecular targets. The yield under stress relative to control is the main parameter, but often the control oyield is low in resistant lines. A review Is in http://www.hindawi.com/journals/tswj/2013/548246/