Genetic studies in Centrosema pubescens benth, a tropical forage legume: the mating system, genetic variability and genetic relationships between Centrosema species

Abstract

In this study, we used microsatellite loci to estimate the outcrossing rate of Centrosema pubescens in open-pollinated populations of 10 progenies that each contained 20 genotypes. The multilocus outcrossing rate was 27%, which suggested a mixed mating system with a predominance of autogamy. The single locus outcrossing rate was 13%. The difference was 0.040, which indicated that only 4% of outcrossing occurs in related individuals. A paternity correlation of 14% suggests that there is a low probability of finding full sibs in the progeny. Cross-amplification of the 26 microsatellite loci available for C. pubescens was evaluated across 11 different Centrosema species. Nineteen of the 26 tested microsatellites were successfully transferable across the Centrosema species. The polymorphism information content and discriminating power evaluated had averages of 0.64 and 0.77, respectively. A total of three clusters were assembled to demonstrate the genetic relationships between Centrosema species. The transferable microsatellite loci should be useful for exploiting the genetic resources of the Centrosema species and determining the outcrossing rate, which are essential for proposing effective approaches for conservation and for establishing strategies for the selection and improvement of Centrosema spp.