MORPHOLOGICAL CHARACTER EVOLUTION OF ASTRAGALUS SECTION INCANI DC. (FABACEAE) BASED ON NUCLEAR AND PLASTID DNA SEQUENCES

Section Incani is one of the most species-rich section of Astragalus, ranging throughout Southern Europe, North Africa, Turkey, Iran, central Asia and Caucasus. Ninety-two of 140 species in the section were analyzed using nuclear ITS and chloroplast rpl32-trnL(UAG)markers representing the full range of morphological variation and geographical distribution. The NeighborNet analysis revealed two major lineages, reflecting the biogeographical distribution of sect. Incani. This analysis postulates an east-west pattern of dispersal revealing a major phylogenetic split between eastern and western lineages. A large assemblage (lineage II) comprises the great majority of species of section Incani s.s. from west and northwestern Iran and Turkey along with A. incanus and A. monspessulanus, both restricted to southern Europe and exhibits the bulk of species diversity. We used Mesquite software to reconstruct patterns of evolution of morphological characters within the section. Six morphological diagnostic characters (life form, corolla color, leaflet number, presence or absence of bracteole, hair color of calyx and the bracts color) were mapped on the concatenated tree using Mesquite software. The reliance on morphological characters alone in the delimitation of species in Astragalus sect. Incani may well lead to erroneous phylogenetic results and thus to incorrect taxonomic conclusions.