KARYOTYPE STUDIES AND OBSERVATION ON PLOID VARIATION IN FOUR CUCUMBER CULTIVARS(CUCUMIS SATIVUS L.)

The karyotype of somatic chromosomes is 2n=14=14m(2SAT). All chromosomes are metacentric in all the four cultivars studied, with only one pair of satellite chromosomes in each cultivar. Two cultivars have one secondary constriction. Three ploid levels of somatic cells, 3n, 4n, and 6n are found. The higher is the ploid level, the lower is the frequency of polyploid cells. The number of polyploid cells varies with cultivars. The causes of morphological and ploid variation in cucumber chromosomes are discussed.