A MOLECULAR AND EMBRYONIC STUDY OF APOMIXIS IN CASSAVA (MANIHOT-ESCULENTA CRANTZ)

In cassava, apomixis fixes heterosis and avoids transmission of system ic pathogens which complicate vegetative propagation of the crop. A co mbination of evidence from maternal inheritance of RAPD markers and th e structure of the embryonic sac in large progeny sets of two distinct genotypes have further confirmed the occurrence of apomixis in cassav a. We could advance further on earlier reports of the detection of apo mixis in four ways: (1) we could arrive at an estimate of the rate of facultative apomixis in the range of 2%; (2) we detected the occurrenc e of apomixis in a second genotype, derived from a different interspec ific cross; (3) apomictic behavior was demonstrated in an F-1 individu al and (4) parallel embryonic evidence was generated that corroborate the potential occurrence of apomixis by apospory. The fact that apomix is was detected in an F-1 interspecific hybrid hints to the possibilit y of directly transferring genes for apomixis from a wild relative to cultivated cassava.