A Tetraploid Allium cepa from Bangladesh

Abstract

1. A tetraploid Allium cepa originating from a Bangladesh stock is described.
2. Comparison with the diploid stock shows that the low frequency of bridge and fragment formation, and micronuclei present at meiosis, has been replaced by a very high frequency of both, in the tetraploid.
3. Evidence is presented that it is an autotetraploid, the result of fusion of unreduced gametes, or of parthenogenesis.
4. The tetraploid is characterised by a bi-modal size range of pollen grains, and complete sterility.