Comparative study of the karyotypes of two Vigna sub species

Abstract

The chromosomes of the two Vigna sub species were individually identified in order to gain insight into variations in the chromosome morphology that may contribute to interspecies cross incompatibility. Diploid chromosome number of 22 was established for V. unguiculata (TVu14476) while V. unguiculata ssp. dekindtiana var. pubescens was different with mitotic chromosome number of 23. The total lengths of chromosome ranged from 2.0 – 5.2 μm. Identification of individual chromosomes was carried out using chromosome length, ratio between arms and centromeric positions. The 11 pairs of homologues were classified as metacentric, submetacentric, subtelocentric and acentric using a centromeric index which was between 0 and 50. Idiograms were constructed for each Vigna sub species based on the average length of each chromosome.

Key words: Triploid, metaphase and mitosis.