Cytologia 69(2): 203–208, 2004

Two F1 hybrids one between wild C. annuum var glabrisculum and C. frutescens (H1) and another between wild C. annuum var antigua and C. frutescens (H2) were obtained. Cytogenetic analysis of F1 hybrids showed that the parental genomes differ from each other by 2 or 1 translocations, 1 inversion and some minor structural alterations leading to reduced homologies between the respective parental genomes. Meiotic irregularities pollen and seed sterilities were higher in H2 than in H1. Probable reasons for the differences in respect of their crossability relationships, chromosome pairing and fertilities in non-rearing of reciprocal hybrids are suggested. The role of chromosome structural changes in genome differentiation is suggested. Isolating mechanisms viz., hybrid inviability and hybrid weakness in the reciprocal cross and hybrid sterility in the F1 hybrids are in operation.