Construction of an Intraspecific Linkage Map and QTL Analysis for Earliness and Plant Height in Lentil

Earliness and plant height traits are key targets in lentil (Lens culinaris Medikus) breeding and are quantitatively controlled. Recombinant inbred lines (RILs) are useful in genetic mapping studies of quantitative traits. The objectives of this study are to develop a genetic map and identify genome regions associated with earliness and plant height using RILs derived from a cross between 'Eston' x PI320937. Number of days to flower and plant height at flowering were collected at two Saskatchewan locations, Saskatoon and Floral, in 2004. Two hundred and seven amplified fragment length polymorphism (AFLP), simple sequence repeat (SSRs), and random amplified polymorphic DNA (RAPD) markers were used to genotype 94 RILs. The markers were ordered into 12 linkage groups (LGs) with a total length of 1868 cM. The average density of markers was 8.9 cM. The AFLP markers were distributed throughout the genome, whereas RAPD and SSR markers were located on LG4 to LG9 only. A resistance gene to anthracnose [caused by Colletotrichum truncatum (Schwein.) Andrus & W.D. Moore] and a quantitative trait locus (QTL) to ascochyta blight (caused by Ascochyta lentis Vassilievsky) were mapped previously on LG6. Quantitative trait loci affecting earliness and plant height were identified on LG1, LG2, LG4, LG5, LG9, and LG12 at Saskatoon and Floral evaluation locations and explained 37 to 46% and 31 to 40% of the total variation, respectively. Earliness QTLs that were consistently expressed at both locations were concentrated on LG4 and LG12, and markers flanking these QTL regions could be good candidates for marker-assisted selection.