TRANSFERING THE Lr14a GENE FROM BREAD WHEAT TO DURUM AND ITS EXPRESSION AGAINST LEAF RUST

Abstract

The origin of the resistance gene Lr14a against leaf rust (Puccinia triticina E.) is the tetraploid wheat ‘Yaroslav emmer’ (Triticum dicoccum L.). In Mexico, all the important rust races attacking bread wheat (T. aestivum L.) are virulent to this gene. However, races attacking durum wheat are avirulent to Lr14a. The presence of Lr14a in several bread wheat cultivars and wild tetraploid species have been determined, but not in durum wheat. The Lr14a gene was transferred to the cultivar ‘Altar C84’ using the monogenic bread wheat line ‘RL6013’ (Selkirk/6*Thatcher) with the durum wheat ‘Altar C84’ and a backcross to ‘Altar C84’. In order to determine the genetics of the resistance of the durum wheat cultivar ‘Jupare C2001’ resistant to the leaf rust race that overcome the ‘Altar C84’ resistance, and to determine if ‘Jupare C2001’ carries Lr14a, ‘Jupare C2001’ was crossed with ‘Altar C84’ and ‘Altar C84’+Lr14a. The response of Lr14a to the infection of leaf rust in seedlings to races BBG/BN and BCG/BN which are virulent to ‘Altar C84’ is heterogeneous whit large urenidiums (X to X+ in the 0-4 scale) in both bread and durum ‘Altar C84’ background. In adult plant stage to the same races, Lr14a confers near immunity. For better and effective expression of the resistance that Lr14a gene confers against the leaf rust races preferably attacking bread wheat, is necessary the ‘Altar C84’ gene.