Identification of markers associated with genes for rust resistance in Lens culinaris Medik.

Abstract

Lentil rust caused by Uromyces vicia-fabae (Pers.) Schroet is one of the most important diseases of lentil in South Asia, North Africa and East Africa. This disease is usually observed during late flowering and early podding stages. Early infection accompanied by favorable environmental conditions can result in complete crop failure and huge economic losses. Therefore, breeding for resistance against this pathogen is one of the major challenges for the breeders in those regions. It is important to identify resistance sources and to determine the location of the genes for resistance in the lentil genome. Since field screening is often difficult due to the unpredictable nature of the disease, selectable molecular markers can be useful tools to assist lentil breeding and complement field screening and selection for resistance. To map the genes for resistance, a recombinant inbred line (RILs) population composed of 220 RILs was developed from a cross between a rust resistant line, ILL-4605, and a susceptible line from Bangladesh, ILL-5888. Phenotyping of the RIL population was carried out during 2006-2007 and 2008-2009 cropping seasons at the Pulse Research Center, Ishurdi, Bangladesh. There was a lack of uniformity of disease pressure in the 2006-2007 cropping year causing inconsistencies between replicates. Nevertheless, we were able to choose clearly resistant and clearly susceptible RILs for selective genotyping using markers previously placed on our lentil genetic map. One of the 62 markers used for selective genotyping proved to be linked to the gene for resistance. The identified sequence related amplified polymorphism (SRAP) marker, F7XEM4a, was estimated to be 7.9 cM from the gene for resistance. The F7XEM4a marker could be used for marker assisted selection for resistance; however, additional markers closer to the resistance gene are needed.