Further studies on karyomorphology of the genus Indigofera L. (Fabaceae-Papilionoideae)

Abstract

The present communication deals with the chromosome number and karyotype analysis of seven species of the genus Indigofera. The karyotype study is made for the first time in the species investigated here. Among the seven species studied, four are diploids with 2n=16 (I. vicioides, I. arrecta, I. duthiei and I. spicata), one is a tetraploid with 2n=32 (I. angulosa) and two are hexaploids with 2n=48 (I. heterantha and I. amblyantha). The basic chromosome number x=8 for the genus is supported by this work. Karyotype analysis revealed that I. duthiei is primitive and I. amblyantha the advanced, the five other species are being intermediate be-tween these two. The chromosomes showed only nearly median and nearly submedian centromeres. The karyotypes further, show that structural changes and to a certain extent polyploidy might have played an important role in speciation and evolution of the genus.