Cytological Studies in West African Diploid <i>Solanum melongena</i> L. var. Bassawa

Abstract

The haploid number of chromosomes in S. melongena var. Bassawa is found to be 12. Frequencies of chiasmata at diplotene and diakinesis are analysed. The chiasma frequency per bivalent at diplotene and diakinesis varied from 2.2 to 1.3 respectively.The association of chromosomes in three and four occurred in 21.29% cases observed. The occurrence of high frequency of multivalents in a diploid seemed to indicate the presence of translocation interchanges in S. melongena var. Bassawa.The frequency of univalents varied from 4.63 to 5.10%. Sturctural changes and gene mutation are probably responsible for failure of pairing among pairable chromosomes. The behaviour of univalents varied, they either pass to poles or lag and divide. The division and elimination of univalents cause unequal distribution of chromosomes on second metaphase plates. Univalents and fragments which failed to be included in the daughter nuclei formed micronuclei (7.4%).Chromatid bridge formation varied from 5.0 to 5.25% in the first and second anaphases respectively. The chromosome irregularities and abortion of pollen grains (38.3%) are presumably due to gene mutation.The spontaneous chromosome aberrations and partial sterility indicate that the diploid S. melongena var. Bassawa is presumably of hybrid origin.