Development of a co-dominant DNA marker tightly linked to gene tardus conferring reduced pod shattering in narrow-leafed lupin (Lupinus angustifolius L.)

The reduced pod shattering gene tardus is one of the most important domestication genes in narrow-leafed lupin (Lupinus angustifolius L.). In development of a molecular marker linked to the tardus gene, we incorporated the concept of marker validation during the initial candidate marker identification stage. Four dominant microsatellite-anchored fragment length polymorphism (MFLP) markers were identified as candidate markers based on their banding patterns in an F8 recombination inbred line (RIL) population. One specific marker best correlating with phenotypes in the representative germplasm was selected and converted to a simple PCR-based marker. This established marker, designated as “TaLi”, is located at a distance of 1.4 cM from the tardus gene. DNA sequencing revealed six insertion/deletion sites between the non-shattering marker allele and the shattering marker allele. Validation of marker TaLi on 25 domesticated commercial cultivars and 125 accessions of the lupin core collection found a 94% marker and tardus phenotype match. Marker TaLi is the first simple PCR-based marker that can be widely used for non-shattering pod selection in narrow-leafed lupin breeding program.