Molecular marker based detection of leaf rust resistance gene Lr34 in Indian bread wheat (Triticum aestivum L.)

Leaf rust is one of the most destructive diseases of wheat causing huge economic losses throughout the world. Several leaf rust resistance genes have been identified and genetically mapped, some of which have also been cloned including the adult plant resistance gene Lr34. Selection of wheat genotypes carrying Lr34 can be accomplished with the help of expression of a morphological marker leaf tip necrosis (LTN) which is linked with Lr34. However, recording of LTN under field conditions is time and labor intensive thereby slowing down the process of selection of desirable genotypes. Use of molecular markers which are tightly linked to Lr34 can be more efficient in precise identification of lines carrying this gene in a short span of time. We selected a total of seven such markers that were earlier reported to be linked with Lr34. The objective of the study was to assess the suitability of these markers in distinguishing Indian bread wheat genotypes carrying Lr34 from those which lacked Lr34. The haplotype analysis suggested that one STS marker (csLV34) and two gene specific markers (cssfr2 and cssfr5) could distinguish wheat genotypes carrying Lr34 from those lacking it. Use of these markers in breeding program can accelerate the speed of selection of desirable genotypes.