QTLs from Wild Emmer Wheat Improve Drought Resistance in Modern Wheat Cultivars

The potential of QTL alleles from wild emmer wheat (Triticum. turgidum ssp. dicoccoides), to enhance drought resistance in cultivated wheat was studied. Six QTLs conferring drought resistance and related physiological traits were introgressed via marker assisted selection into four elite durum (T. turgidum  ssp. durum) and bread wheat (T. aestivum L.) cultivars.

BC₃F₃ and BC₃F₄ near isogenic introgression lines (NILs) were evaluated in 2012-13 (Exp1) and 2013-14 (Exp2) for their drought responses in a rain-protected screenhouse under well watered (~700 mm) and water limited (~325 mm) treatments.

NIL-B-7A-2, introgressed with a QTL on chromosome 7A, in the background of bread wheat (cv. Bar-Nir), exhibited under water limited conditions significantly higher grain yield (160%) compared with its recurrent parent, consistently over the two experiments. This NIL exhibited higher spike number per plant and grain weight, without a modification in phenology. In Exp2, this NIL showed under drought significantly higher osmotic adjustment and improved photosynthetic capacity than the recurrent parent, which may have contributed to its drought resistance.

NIL-U-2B-3 introgressed with a QTL on chromosome 2B, in the background of durum wheat (cv. Uzan), exhibited in Exp2 under both treatments greater grain yield (~200%), spikes number and grain weight compared with its recurrent parent, without a modification in phenology.

These promising results provide evidence for the potential of wild emmer QTLs to improve drought resistance in cultivated wheats, thus paving the way to improve wheat productivity under drought and expand wheat cultivation into semi-arid zones, where it is not grown today.