Variation in tolerance of prolonged drought was identified among a set of single chromosome bread wheat substitution lines, involving the replacement of each cv. Chinese Spring chromosome in turn with its homologue from a synthetic hexaploid (Triticum dicoccoides × Aegilops tauschii). Water stress was applied under controlled conditions by limiting the supply of water to 30% from 100% aqueous soil. The reaction to the resulting long-term drought stress was quantified by three indices, based on grain yield components. Enhanced drought tolerance was associated with the presence of donor chromosomes 1A, 5A, 1D, 3D, 5D and 6D, and enhanced susceptibility with chromosomes 3A, 4B and 7D.
For six wheat varieties with different quality it was shown that GSH-dependent protein-disulphide oxidoreductase (TPDO) increases the activity to the third week after anthesis, a period of maximum synthesis of storage proteins in wheat kernels. The study revealed a correlation between TPDO activity in maturing kernels and dough stiffness. The addition of exogenous TPDO to flour significantly increased dough extensibility (from 17 to 49% for cultivars with different quality), which implies the ability of the enzyme to disrupt SS bonds in high-molecular weight gluten polymers.