DETERMINATION OF THE NATURE OF TETRAPLOIDY IN CASSAVA THROUGH MEIOTIC ANALYSIS

Abstract

The prevalence of normal bivalent pairing at diakinesis and metaphase I and the high percentage of cells having regular meiosis suggest that cassava (Manihot esculenta Crantz) is an allotetraploid and not an autotetraploid. Based on the results, cassava seems to be a segmental rather than a true allotetraploid as indicated by the presence of multivalents and univalents in 29% of the total meiotic cells observed. This implies partial homology between the chromosomes of the species resulting in segmental pairing of homologous chromosomes. Therefore, cultivated cassava is a segmental allotetraploid with a basic chromosome number of x = 9 and a chromosome number of 2n = 4x = 36.