Summary Four specimens of the genus Allium, viz. A. tuberosum, A. cepa (Local), A. cepa (Indian large bulb) and A. cepa (Indian small bulb), were cytogenetically studied. In addition, DNA fingerprinting by using RAPD was also carried out to make a phylogenetic dendrogram. Allium tuberosum was found to possess 2n=32 chromosomes. On the other hand, 2n=16 chromosomes were observed in the other three specimens. The four specimens showed distinct centromeric formulae, which were 16m+12sm+4ac in Allium tuberosum, 10m+4sm+2ac in A. cepa (Local), 8m+8sm in A. cepa (Indian large bulb) and 9m+7sm in A. cepa (Indian small bulb). This result indicated that Allium tuberosum and A. cepa (Local) possessed more heterogeneous karyotypes. Satellites were found in Allium tuberosum, A. cepa (Indian large bulb) and A. cepa (Local) in different stains. In A. cepa (Indian small bulb), heteromorphicity in respect of centromeric position indicated the occurrence of a deletion at the short arm of the respective chromosome. The four specimens of Allium have distinct CMA-and DAPI-banding patterns. The number, location, intensity and percentage of GC-and AT-rich repeats were different in these specimens. With the help of CMAand DAPI-banding it was possible to mark certain chromosomes specific for each specimen. Each specimen showed characteristic RAPD fingerprinting. The unique RAPD fragments could be used as markers for the respective specimens. The karyotype and RAPD data did not support the large bulb specimen as an autopolyploid of the small bulb specimen, but rather found maximum similarity between the two specimens. Moreover, the karyotype data of A. tuberosum obtained in this study was different from earlier reports, and thus needs a peer revision of its taxonomic status.

Summary Three varieties of Lathyrus sativus L. released from Bangladesh Agricultural Research Institute (BARI), viz., BARI Khesari-1, BARI Khesari-2 and BARI Khesari-3, were studied cytogenetically and at the molecular level by using RAPD for genomic characterization. The three varieties were found to posses 2n=14 chromosomes. The karyotype formulae of BARI Khesari-1 and BARI Khesari-2 are 8m + 6sm, while it is 10 m + 4sm in BARI Khesari-3. After orcein and CMA staining, one to two very small chromosome-like bodies were found in some cells of BARI Khesari-1, whereas no such body was observed after DAPI staining. Due to their unique features these can be considered as GC-rich heterochromatic B-chromosomes. In BARI Khesari-2, two pairs of satellites were found, while only one pair was present in BARI Khesari-3. The inverted position of satellited regions indicated the probable occurrence of homozygous inversion. An indication of paracentric inversion regarding DAPI-banding pattern was found in pair V of BARI Khesari-2 and thus could be considered as marker chromosomes for this variety. The three varieties have distinct CMA-and DA-PI-banding patterns. In BARI Khesari-2, a total of 12 C-bands were found on 10 chromosomes (out of 14 chromosomes). On the basis of band position and length, a deep correlation between C-banding and DAPI-banding pattern was found suggesting the heterochromatic nature of DAPI bands. Each variety showed different RAPD fingerprinting with 59.09% polymorphisim. In addition, a number of variety-specific unique RAPD bands was observed. Therefore, each variety could be characterized on the basis of karyotype and RAPD analysis.