DIAGNOSIS OF DURUM-WHEAT YIELD IN AGRICULTURAL FIELDS UNDER SEMIARID CONDITIONS IN TUNISIA

Diagnosis of durum wheat yield in agricultural fields under semi-arid conditions in Tunisia. In order to determine the main limiting factors of wheat production in a semi-arid area of Tunisia, growth, yield, and yield components of durum wheat were measured in agricultural fields over 2 years with contrasting rainfall. They were compared with controls established under experimental conditions and published in a previous paper. Dry matter production, yield, and yield component were highly variable among and within a climatic year. Yield was mainly related to grain number for both years; grain and ear number variability depend on growth before anthesis. Comparison with the controls allowed us to determine the main periods when limiting factors applied. Poor seedbed control, weed infestation, nitrogen supply, and water availability during the growing season, were all identified as main limiting factors. Some of these are related to constraints from the cropping systems.