Cytology of Induced Desynaptic Mutants in Rice.

Abstract

In the desynaptic plants at pachytene no single unpaired threads were noted and pairing was apparently complete. The desynaptic mutants were classified into 'medium strong' based on the number of univalents present at diakinesis. Mean number of chiasmata per bivalent was significantly less in the mutant plants when compared to normals. In the desynaptic plants, when the mean bivalent frequency was less than three, there was no clear metaphase I stage, but it was rather a metaanaphase stage. The unoriented chromosomes at metaphase I lead to highly irregular distribution of chromosomes ranging from 11 : 13 to 4 : 20 at anaphase I. Variable number of microspore formation per PMC was observed at tetrad stage. Formation of micronuclei was also observed with considerable frequency. Complete pollen and seed sterility was observed.