No abstract

Summary A molecular cytogenetic survey of Cucumis sativus L. revealed a chromosomal polymorphism among 2 European pickling cultivars of 'Borszczagowski' and 'Monastyrski', and one Japanese cultivar of 'Zibai' by fluorescent banding method with chromomycin A 3 (CMA) and 4Ј,6-diamidino-2-phenylindole (DAPI), and fluorescence in situ hybridization (FISH) with the probes of 5S, 45S rDNA and telomere repeat sequences. Heterochromatic banding polymorphism was found in some chromosomes with CMA and DAPI staining, whereas no chromosomal polymorphism was found in FISH. Thus, the FISH allowed us to identify all of homologous chromosomes in each cucumber cultivars, while CMA and DAPI banding showed an easy detection of the polymorphism in cucumber chromosomes, even in close related cultivars between European pickling cultivars.

Summary Using a base-specific staining method, three Japanese cultivars of Momordica charantia were investigated. The present method using enzymatic digestion produced a high level of well-spread metaphase chromosome complements. The cultivars investigated showed the same somatic chromosome number 2n=22. In condensation behavior from prophase to metaphase, most chromosomes of all cultivars in this study had early condensing segments at the proximal regions. Moreover, at prophase or earlier stage of metaphase, most chromosomes observed had decondenced segments at the distal regions in both arms. Judging by the determination of centromere positions, the chromosome complements at mitotic metaphases in three cultivars consisted of 22 metacentric chromosomes. Moreover, similar sizes and shapes of the chromosomes indicated that the karyotypes of M. charantia cultivars were symmetrical. In contrast, fluorescent staining showed different sizes and numbers of chromycin A 3 (CMA) positive and 4′,6-diamidino-2-phenylindole (DAPI) negative (CMA + DAPI ) satellites among cultivars. Four CMA + DAPI satellites were observed in M. charantia Abashi-goya and M. charantia Naga-goya, while two satellites were obseved in M. charantia Shiro-goya. All satellites were located at one end of sat-chromosomes. In Shiro-goya, a large size difference of satellites was found between two satchromosomes, which might be homologous chromosomes with polymorphism. Moreover, faintly CMA + DAPI sites were shown at the proximal regions or primary constrictions of most chromosomes in all cultivars.