Effect of water stress at various growth stages on some quality characteristics of winter wheat

A field experiment was carried out in Erzurum (Turkey) on winter wheat to analyse the effect of water stress at different growth stages - fully irrigated (FI), rainfed (R), early water stress (EWS), late water stress (LWS) and continuous water stress (CWS), on some quality characteristics - in the 1995-96 and 1996-97 cropping seasons. Water stress had a substantial effect on most of the quality characteristics. As averages of cropping seasons, CWS, EWS, R and LWS treatments decreased grain yields by 65.5, 40.6, 30.5 and 24.0 %, respectively, compared with the FI treatment. CWS increased grain protein content by 18.1 %, sedimentation volume by 16.5 %, wet gluten content by 21.9 % and decreased 1000-kernel weight by 7.5 g compared with FI treatment. LWS caused an increase of 8.3 % in grain protein content, 8.7 % in sedimentation volume, 10.8 % in wet gluten content and a reduction of 3.8 g in 1000-kernel weight compared with FI. EWS and R increased sedimentation volume and wet gluten content, but decreased 1000-kernel weight compared with FI. The effect of LWS on grain quality was more significant than that of EWS. The results suggest that soil moisture conditions increase grain yield and kernel weight of winter wheat but decrease its quality.