Cytogenetic studies on some Nigerian species of Solanum L. (Solanaceae)

Cytogenetic studies to determine the chromosome number, structure and behaviour of some species of Solanum in Nigeria was carried out. Attempt was also made to induce polyploidy in the species. Comparative analysis of the cytological behaviour of the diploid and polyploid cytotypes was made. The studies show that the somatic chromosome number in the genus Solanum is 2n = 24. Colchiploidisation produced tetraploids with 2n = 48 and aneuploids with 2n = 69. The karyotype analysis indicates that the chromosomes were generally very small. There were also slight variations in centromeric positions and arm lengths. Meiotic behaviour of the chromosomes involved a combination of bivalent and multivalent associations especially at the polyploid levels. The significance of this work in the understanding of cytogenetic behaviour of plants and crop improvement efforts are discussed.