Variation in Chromosome Number and its role in Speciation in Dracaena Metallica Hort.

ABSTRACT

From the study of somatic chromosomes of Dracaena metallica Hort., which shows a high degree of variation in chromosome number, and which is propagated exclusively by vegetative means, it is clear that the chromosome numbers have got some common characteristics in all the offshoots. Counting of a large number of plates in the root tips of different offshoots shows the repetition of almost similar types of chromosome numbers which tend to remain as multiples of 7. In spite of this homogeneity in the offshoots, differences in the tendencies of variation were noticed, particularly in the occurrence of the most frequent chromosome numbers. In the long run, such differences may lead to the production of new species having distinct chromosome complements.