Drought stress is one of the most important environmental factors reducing cereal yields. The genetic
and physiological bases of drought tolerance in durum wheat was investigated by QTL mapping and by
mapping candidate genes derived from differentially expressed genes and previous investigations. A
recombinant inbred population derived from a cross between two durum (Triticum turgidum L. var
durum) parents Jennah Khetifa and Cham1 that exhibit contrasting traits for drought tolerance was
employed. Twelve known genes and 103 differentially expressed sequence tags (dESTs) were surveyed
and 55 detected polymorphism between the two parental lines. In total, 162 loci including 6 known
genes, 37 dESTs, and an additional 119 markers that were unlinked in the previous map have been
merged with 306 previously mapped markers to produce a new map with 468 loci. Single point analysis
and composite interval mapping were used to identify the genomic regions controlling traits related to
drought stress. Significant QTL were identified for canopy temperature, photosynthesis-related parameters and water status index. One hundred and seventy eight markers, including 6 candidate genes
and 19 differentially expressed sequences were associated with QTL for drought tolerance traits. The
results indicate that there is considerable potential for improving drought tolerance of durum wheat by
using marker-assisted selection
