NEW C-BANDING PATTERN FOR CHROMOSOME IDENTIFICATION IN CUCUMBER (CUCUMIS-SATIVUS L.)

A chromosome study of cucumber, C. sativus L., was performed using orc ein and C-banding techniques. The diploid and tetraploid plants invest igated here showed the somatic chromosome numbers 2n = 14 and 28, resp ectively. The haploid chromosome complement was composed of five metac entric and two submetacentric chromosomes. All C. sativus chromosomes had clearly visible C-bands, and each chromosome could be identified u nequivocally after C-banding staining, with 13 C-bands appearing in th e haploid complement. The haploid complement had a 44.9% ratio of tota l C-band length to total chromosome length. Chromosomes 1, 2, 4, 5 and 7 had stable C-bands. Three large, dark C-bands appeared at the proxi mal regions of chromosomes 1 and 2. Chromosome 1 had quite a large C-b and and with a 68.4% ratio of C-band length to short arm length. Chrom osome 2 also had quite a large C-band in the pericentromeric region wi th a 57.6% ratio of C-band length to the full length of this chromosom e and possessed an elongated primary constriction in early metaphase. In prometaphase, chromosome ? showed that the long arm was completely separated from the short arm. The number of secondary constrictions co uld not be clearly observed because these chromosomes are small and th ey could not be counted in every metaphase cell. However, six chromoso mes seemed to have secondary constrictions in the diploid plants. Two silver-stained bands were observed at primary constrictions of two of the large chromosomes.