Morphology of the pachytene chromosomes ofPennisetum purpureum schumach

The morphology of the pachytene chromosomes ofPennisetum purpureum was studied. On the basis of relative lengths and arm ratios it was possible to identify them individually. They are numbered 1 to 14 in the order of their decreasing lengths and diagnostic characters are given for each chromosome. The first and the fourteenth chromosomes, the longest and the shortest of the complement respectively, are the nucleolus organizing chromosome. In all the fourteen chromosomes the centromeres are flanked by deep staining regions. This feature is common to the two species.P. typhoides andP. purpureum. Seven out of the fourteen chromosomes have terminal knobs in their long arms. This is a feature in which it differs from the other seven chromosome species.Pennisetum typhoides. These knobs, however, are not present uniformly in all populations; material obtained from Ghana did not show these knobs.