Mapping of foliar disease resistance genes and genes for agro-morphological traits in Lens culinaris Medik

Stemphylium blight (caused by Stemphylium botryosum Wallr.) and rust (caused by Uromyces fabae (Pers.) J. Schroet.) are important foliar diseases of lentil (Lens culinaris Medik.). To map the genes for resistance to these two diseases, F6 derived F7 recombinant inbred line (RIL) populations were developed by crossing ILL-5888 (susceptible to stemphylium blight and rust) to ILL-6002 (resistant to stemphylium blight) and ILL-4605 (resistant to rust). One population was used to map QTLs for resistance to stemphylium blight and genes for six agro-morphological traits. The other population was used to map the gene for resistance to rust.;The genetic linkage map used to map QTL for resistance to stemphylium blight comprised 139 markers distributed over 14 linkage groups. Three significant QTLs were detected for stemphylium blight using data recorded at the Pulse Research Center (PRC), Ishurdi, Bangladesh in 2009; whereas, one QTL was detected using 2007 data. QTL QLG480-81 was common to both years and accounted for 25.2% and 46% of the phenotypic variation for blight scores, respectively, for the two years.;Differential rust reactions were observed in two seasons at Bangladesh. Genotyping indicated that the gene for resistance was located on linkage group3 and 7.9cM from SRAP marker F7XEM4a.;The gene rich QTL region (QLG482-83) accounted for a significant amount of the phenotypic variation for days to flowering, seed diameter and 100 seed weight. Growth habit and cotyledon color are conferred by single genes. Prostrate growth habit was dominant over erect and red cotyledon was dominant over yellow.;The results of these experiments indicate that selection for resistance to stemphylium blight and rust can be made using linked molecular markers. Additional fine mapping of these genes is needed to identify more closely linked markers and improve the prospects for marker assisted selection. Validation of these putative markers for resistance genes is also needed.