Mutants of durum wheat with alterations in tissue affinity for strongly bound water

Mutants of Triticum durum Desf, var Trinakria were identified by screening in the field, pedigree M5 collections from sodium azide (SA) treated seeds, for changes in leaf affinity for strongly bound water. This was estimated applying a new method that consists of a simplified analysis of the differe nces in water adsorbed by the leaf segments at two temperatures. A total of ten M5 lines were identified and tested for differences for water sorbed ( DWS) in a growth chamber, under well watered and water deficit conditions. Subsequently, three mutant lines were isolated that had DWS values greater than Trinakria and a mutant line that expressed the lowest DWS values under well watered conditions-and very high DWS values under drought stress. Wit h the exception of this line, whose affinity for water was drought-inducibl e, there was a high degree of correlation between tissue affinity for water expressed in the field and in the growth chamber. These findings suggest t hat the trait is genetically transmitted and that the screening procedure i s robust. The availability of the mutants should provide new opportunity to investigate the genetic and physiologic basis of bound water. (C) 1999 Els evier Science Ireland Ltd. All rights reserved.