Genetic Diversity and Lineage Based on SSR Markers of Two Genomic Resources among Trifolium Collections Held within the Australian Pastures Genebank

Abstract

Trifolium alexandrinum, an important forage legume, suffers from narrow genetic base. The present investigation was envisaged to reveal the inter- and intra-species genetic diversity and lineage among 64 accessions, representing a global collection, of T. alexandrinum; it’s two probable progenitor species (T. salmoneum and T. subterraneum) and the three genetically distant species (T. repens, T. vesiculosum, T. michelianum). A set of Simple Sequence Repeats (SSR) primer-pairs developed from T. alexandrinum have shown to amplify alleles across the species under study, suggesting utility of the newly developed resource for assessing molecular diversity among Trifolium species. These SSRs markers together with previously reported SSRs, derived from T. repens, enabled to reveal high intra-species polymorphism in T. alexandrinum and successfully discriminate different species investigated in this study. The diverse accessions determined herein provide a superior resource for further breeding of T. alexandrinum. High allelic similarity of T. alexandrinum with T. subterraneum and T. salmoneum indicated close relatedness among the species, suggesting polyphyletic evolution of T. alexandrinum.