Abstract
A meiotic mutant, inducing the formation of coenocytes in pollen mother cells, is reported in three lines of barley, viz., (BHS 24×Mari), HBL 175 and (Liguleless×USDA 606). The mutation appears to be of induced nature in BHS 24×Mari due to irradiation with gamma rays, of spontaneous nature in HBL 175 and of induced nature due to colchicine in Liguleless×USDA 606. It is characterised by fusion of variable number of PMCs at pre-synaptic or post-synaptic stages of meiotic prophase I, resulting into the formation of plasmodial masses or polyploid nuclei on their coalescence, irregular congression and subsequent distribution of chromatin, and formation of microspores of highly variable size and shape. The present studies establish that the phenomenon of coenocytism causes tip sterility and that the frequency of fused PMCs is higher in the tip region of the spike than in the mid or base region. These studies also indicate the occurrence of such a phenomenon during megasporogenesis too, though it needs confirmation through direct observation.
