Identifying leaf rust resistance gene Lr19 in durum wheat using simple sequence repeat (SSR) marker

Leaf rust, caused by Puccinia triticina Eriks., is an important disease affecting durum wheat ( Triticum turgidum ssp. durum) worldwide, particularly in the Mediterranean region. The disease can be controlled through the use of plant host resistance. Based on seedling resistance tests of 103 durum genotypes against a bulk of P. triticina , urediniospores were previously collected from Syria and Lebanon during 2007/08 and 2008/09 growing seasons. Percentage of resistance in the durum set tested was up to 52%. The resistant genotypes might have one of the following resistance gene(s): Lr15, Lr 19, Lr 24, Lr 25, Lr 27 +31, Lr 28 and Lr 29. Results revealed that the Gb/130-bp polymorphic band was linked to Lr19 and Sr25. In this study, twelve genotypes carrying resistance to Lr19 and Sr25 have been identified (Azeghar2, Rutucha1, Ammar9/Azeghar2, Ammar9/Terbol97-4, T.polonicum 9/Ch1//Icamor-TA04-68/3/Icamor-TA04-69//(Lahn/ Ch1)2519, Arislahn5//Icamor-TA04- 63/Icasyr1, T.dicoccum 1/Ch1//Ammar8/3/Bonadur/Icamor-TA04-63, Mrb3/ T. urartu 500651/4/Icamor- TA04-63/3/Bcr/Gro1// Mgnl1, SwAlg/Gd1-81 //Ch1-48, Icamor-TA04-1//Mgnl3/Ainzen1, 319-ADDO/5/D68-1- 93A-1A//Ruff/Fg/3/Mtl5/4/Lahn, and Mrf1/Stj2/3/1718/BT24//Karim). Promising results on Gb/130-bp and genotypes carrying Lr19 and Sr25 will be used in a marker assisted selection of the durum breeding programs in the Mediterranean region. Key words : Puccinia triticina, durum genotypes, Syria, Lebanon, Lr19, Sr25, Gb primer.