Occasionally, conventional staining techniques do not distinguish chromosomes of similar morphological features. In this case, Giemsa C-and N-banding techniques have helped identify these chromosomes (Singh and Tsuchiya, 1981b; Schlegel, Melz, and Nestrowicz, 1987; Gill, Friebe, and Endo, 1991). Furthermore, the recent adaptation of the

in situ

hybridization technique for plant chromosomes, particularly for cereals, has also facilitated the process of distinguishing morphologically similar chromosomes.