Grain quality of durum wheat germplasm as affected by heat and drought stress at grain filling period

摘要

Various physical and chemical screening tests can be used to predict pasta-cooking quality of the experimental lines in a durum wheat breeding program. In the present study, 300 durum wheat genotypes were evaluated for kernel characteristics contributing to end-product quality under irrigated field conditions. This study was conducted during 1998 and 1999 growing seasons at two sites of Abarkoh and Isfahan located in central of Iran. A combination of heat and drought stress occurred at Abarkoh regionduring grain filling period where air temperature ranged from 34 to 42°C which accompanied with a hot and dry wind. The maximum temperature exceeded 8-10°C from the long-term averages in May and June in this area during 1998 and 1999 growing seasons.The following criteria were used: test weight, grain hardiness, protein content, wet and dry gluten contents and sodium dodecyl sulfate (SDS)-sedimentation volume. Variation among genotypes for grain quality characteristics indicated and genotype responses to the environmental conditions varied. Statistical analysis using a paired t test indicated a significant differences (P<0.01) between two regions for all grain quality characteristics and the highest values were recorded where a combination of heatand drought stress occurred at grain filling period in Abarkoh region. The results also revealed that some genotypes have a similar protein content ranking under both heat and dry environment and optimal environment, while others have a substantially different ranking under optimal and stressed environments. Genotypes Osta/Gata, ICDW 7639 and PI40100 provide a good example of the former response, where their protein content ranked similarly in both of stressed and optimal environments.