Ionizing radiation mediated cytological manifestation in microsporogenesis of Brassica campestris L. (Brassicaceae)

Purpose of the present work is to investigate the mutagenic effects of ionizing radiations (gamma rays) on Brassica campestris L. accession no IC363713. Homogeneous seeds of Brassica were irradiated at four doses of gamma rays i.e. 150 Gy, 300 Gy, 450 Gy and 600 Gy by the gamma-chamber type Co at the dose rate of 2 second/Gy. During microsporogenesis, meiotic analysis of young floral buds was carried out in irradiated as well as non-irradiated plant materials. Meiotic study clearly revealed the meiotic malfunctioning of pollen mother cells (PMCs) that had shared copious count of cytological abnormalities namely unorientation, stickiness, precocious movement or fragmentation, secondary association of bivalents, asynchronous division, laggards, tripolarity and chromatin bridge. These aberrations were found to be distributed in all the phases of male meiosis. However, this impairing during meiosis has found to be collinearly associated with doses i.e. inclining tendency of abnormality percentage alongwith increasing doses were registered. Perhaps aforementioned chromosomal aberrations may be introduced by asymmetrical distribution of chromatin material in PMCs, had definitely compromised with pollen fertility, resulting the increased frequency of pollen sterility. Hence, pollen fertility registered, simultaneously, a moderate to sharp fall depending upon the intensity of doses.