Soybean molecular linkage group B1 corresponds to classical linkage group 16 based on map location of the lf2 gene

The seven-leaflet character of soybean [Glycine max L. (Merr.)] is a single recessive trait conditioned by the lf (2) gene. The lf (2) gene is located on linkage group (LG) 16 of the classical soybean genetic map, but it has not been placed on the molecular map. The objective of this research was to identify the location of the lf (2) gene on the soybean molecular map using simple sequence repeat (SSR) markers. A backcross breeding method was used to create three- and seven-leaflet near-isogenic lines in genetic backgrounds of 'Traill', 'MN1401', and 'MN1801'. Eight mapping populations were derived from eight single heterozygous lf (2) lf (2) plants. A total of 482 SSR markers that covered approximately every 10-20 cM of all soybean molecular LG were used to screen the mapping populations for polymorphisms. For the 115 SSRs that were identified as polymorphic, possible linkage between the lf (2) gene and the polymorphic SSR markers was determined. One SSR marker from the LG B1, Sat_272, was linked (LOD > 4.0) to the lf(2) gene in the Traill and MN1401 derived populations, with map distances ranging from 2.8 to 11.2 cM. Two additional markers (a SSR, Sat_270 and a SNP, A588c) located on LG B1 were also polymorphic and were identified as linked to the lf (2) gene in one of the populations. This research was successful in mapping the lf (2) gene to LG B1 of the soybean molecular map and therefore, provides evidence that molecular LG B1 corresponds to classical LG 16.