Development of simple sequence repeat (SSR) markers in Medicago ruthenica and their application for evaluating outcrossing fertility under open-pollination conditions

Medicago ruthenica is a perennial leguminous plant with great economic value for forage production and soil conservation in northern China. Simple sequence repeat (SSR) markers are a major molecular tool for genetic and genomic research that have been extensively developed and used in major crops. However, few are available inM. ruthenica, an important cool-season forage species inChina. Using transcriptome data, we developed 213 polymorphic SSR markers. Additionally, we used these markers to quantify selfing and outcrossing rates of M. ruthenica plants under field conditions. The outcrossing rate was calculated to be 75.9%. The first large set of codominant markers developed for M. ruthenicaand knowledge of its outcrossing behavior should be highly valuable for molecular and traditional biological research.