OPTIMIZING DURUM WHEAT YIELD UNDER SHORT-TERM DRY SPELLS THROUGH VARIETY SELECTION AND IRRIGATION MANAGEMENT

Abstract

ABSTRACT. Wheat production in Tunisia, particularly of durum wheat (Triticum durum Desf.), is increasingly threatened by climatic instability, including recurrent droughts and erratic rainfall patterns. In this context, optimizing yield through integrated varietal selection and irrigation management is critical. This study was conducted to assess the combined effects of variety and irrigation regime on key yield components of durum wheat under sub-humid Mediterranean conditions in northern Tunisia. A factorial field experiment was conducted at the CRRGC (Oued Béja), using two contrasting cultivars, ‘Karim’ (traditional) and ‘Maali’ (improved) under three irrigation regimes: full irrigation, deficit irrigation, and rainfed. Results revealed significant effects of variety, irrigation, and their interaction on biological yield, grain yield, and harvest index (HI). ‘Maali’ exhibited superior reproductive traits, higher spike density, greater grain yield stability, and consistently higher HI under reduced irrigation and rainfed conditions, affirming its suitability for climate-resilient systems. Conversely, ‘Karim’ demonstrated higher biomass under full irrigation but experienced sharp yield declines under water stress, suggesting a dependence on high-input conditions. Moderate deficit irrigation enhanced biomass accumulation and spike number, while maintaining acceptable grain yield, confirming the potential of precision water management in resource-limited environments. Soil analyses showed neutral pH and low salinity, ensuring that treatment effects were not confounded by edaphic factors. The findings emphasize the importance of genotype selection and strategic irrigation in enhancing productivity and resource-use efficiency. These insights contribute to sustainable cereal production under climate change scenarios and support adaptive agricultural planning in the North African region.