Morpho-physiological responses of diverse emmer wheat genotypes to terminal water stress

Emmer wheat (Triticum dicoccon Schrank) is the allo-tetraploid progenitor of the modern wheat and holds genetic variation for tolerance to drought. Water use efficient emmer wheat genotypes are considered better maintainers of yield under water limited environments. However, existing genetic variation for water use efficiency (WUE) in emmer germplasm has not been fully explored nor are the underlying mechanisms of this trait properly understood. Three field selected, contrasting emmer wheat genotypes were assessed at 90% and 50% pot soil water capacity (PSWC) in quadruplicated design for water use response under glasshouse conditions. Significant differences were observed between water treatments and among genotypes for various traits including carbon isotope discrimination (CID) and the grain yield. Water stress had significant negative impact on grain yield but less so in genotypes superior in water use efficiency. The relationship between grain yield and WUE was positive both at 90% and 50% PSWC. Genotypes with lower CID scores had higher WUE and grain yield under water stress. The genetic variation for WUE observed in emmer wheat is a potential resource to improve drought tolerance in hexaploid wheat.