Allium is the medicinally important one of the largest monocotyledonous genera. Taxonomic position of this genus remains controversial. Morphological markers alone are not adequate to achieve correct identification, interspecific relationship and proper taxonomic position of a taxon. In the present investigation, phylogenetic relationship among the four selected species of Allium (A. cepa, A. sativum, A. hookeri and A. wallichii) has been established through dendrogram analysis, based on some morphological, biochemical and cytological parameters. A. cepa and A. hookeri exhibited maximum and minimum bulb size and weight respectively, where as soluble root protein is higher in A. hookeri than rest of the three species. A comparative study based on nucleolar volume and mitotic index of Allium exhibited considerable variation. All the species exhibited mono and binucleolate cells. A. hookeri is only species which exhibits mono, di, tri and tetranucleolate cells. Largest nucleolus is observed in A. hookeri and smallest nucleolus is present in the cells of A. sativum. The A. cepa exhibits maximum mitotic index than the other species under study. Dendrogram analysis exhibits two hierarchical clusters- upper cluster (UC) and lower cluster (LC). A. hookeri is only placed in LC while the rest of the three species are placed in UC. UC has been again sub-divided into two sub clusters- UC1 and UC2. A. cepa and A. wallichii are included in UC1 while A. sativum is placed in UC2. Thus the present study provided useful information for the identification of the taxa, their relationship and delimitation of their taxonomic status.
