Durum wheat quality in Mediterranean environments I. Quality expression under different zones, latitudes and water regimes across Spain

Ten durum wheat genotypes were studied in a total of 10 field trials in three different regions of Spain, associated with two latitudes (north and south) under both irrigated and rainfed conditions during the 1998 and 1999 growing seasons. Different technological and commercial quality parameters were studied: thousand kernel weight (TKW), test weight, vitreousness, ash content, protein content, pigment content and the SDS sedimentation test. The results demonstrated the strong influence of environmental conditions on the majority of quality traits in durum wheat, with growing zones, latitudes and moisture regimes showing the greatest effects. Genotypic effects were mainly observed for pigment content and SDS volume. These appear to be predominantly under genetic control. TKW and protein content were higher in Lleida in the north, probably due to the greater amount of nitrogen applied in comparison with Granada and Jerez in the south. Grain quality under the growing conditions of Lleida, however, was negatively influenced by the high percentages of ash accumulated in the grain. In general, Granada and Jerez provided an acceptable grain quality, and Jerez in particular favoured good semolina colour and higher test weights. Moisture stress increased mainly protein content and vitreousness, and reduced TKW and ash content at both latitudes. It is clear that rainfed conditions in the south offer the best opportunity for production of durum wheat of good quality. # 2002 Elsevier Science B.V. All rights reserved.