A molecular and embryonic study of apomixis in cassava (Manihot esculenta Crantz)

In cassava, apomixis fixes heterosis and avoids transmission of systemic pathogens which complicate vegetative propagation of the crop. A combination of evidence from maternal inheritance of RAPD markers and the structure of the embryonic sac in large progeny sets of two distinct genotypes have further confirmed the occurrence of apomixis in cassava. We could advance further on earlier reports of the detection of apomixis 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 occurrence of apomixis in a second genotype, derived from a different interspecific cross; (3) apomictic behavior was demonstrated in an F₁ individual and (4) parallel embryonic evidence was generated that corroborate the potential occurrence of apomixis by apospory. The fact that apomixis was detected in an F₁ interspecific hybrid hints to the possibility of directly transferring genes for apomixis from a wild relative to cultivated cassava. This revised version was published online in July 2006 with corrections to the Cover Date.