PROSPECTS OF POLYPLOIDIZING CASSAVA, MANIHOT-ESCULENTA CRANTZ, BY UNREDUCED MICROSPORES

Eleven interspecific hybrids of cassava with the wild relatives Maniho t glaziovii, M. pseudoglaziovii, M. dichotoma and M. anomala were exam ined to detect unreduced microspores, The frequency of dyads and triad s was counted, as well as pollen viability. Of these hybrids, the seco nd generation progeny of cassava×M. glaziovii showed a high freq uency of unreduced microspores (3.7%) permitting their selection for f urther manipulation of this character. An association of vegetatively- reproduced genotypes and the occurrence of unreduced microspores has a lso been observed.