Determination of the Nature of Tetraploidy in Cassava Through Meiotic Analysis


Author(s): Celsa F. Armecin and Azucena L. Carpena

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.

Keywords : Cassava. Manihot esculenta. Polyploidy. Chromosome number. Meiosis. Cytology. Genetic improvement.

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