Gamma Rays Induced Cytomictic Variations in Pollen Mother Cells of Cumin ( Cuminum cyminum ) L.

Cytomixis is an enigmatic cytological phenomenon found between proximately situated PMCs reported in Cuminum cyminum L. The transmigration of chromatin material between two adjacent meiocytes was observed at various exposure rate of gamma radiation viz., 100, 125, 150 and 175 Gy in GC-4 variety of cumin. The microsporogenesis study of gamma treated sets reveals intercellular migration through various channels or direct fusion. In the present study, the cytomixis was more frequently noticed at meiosis I as compared to later stage i.e., meiosis II. The rate of recurrence of cytomixis shows gradual increment along with the increasing dose rate of gamma rays. As consequences of cytomixis various aberrant post meiotic products were recorded at later phase of cell cycle. Moreover, in addition to cytomixis other chromosomal abnormalities were also recorded which leads to reduction in pollen fertility. Syncytes were observed at low frequency but have high evolutionary significance as they produce gametes with higher ploidy level. The production of gametes with unbalanced chromosomes can be further exploited in breeding techniques as they are potent variation inducer.