Sodium Azide Induced Complementary Effect of Chromosomal Stickiness in Brassica campestris L

Present investigation reports the mutagenic efficacy of sodium azide with a view to study its effects on meiotic behavior and phenotypic quantitative traits of Brassica campestris L. Seeds were treated with three concentration of sodium azide i.e. 0.3%, 0.5% and 0.7%, along with control. Morphological/phenotypic parameters studied were plant height, number of primary branches, number of secondary branches, seeds/siliqua, husk yield, seed yield and 1000-seed weight. All these traits showed the significant positive shifts in mean at 0.3% and 0.7% doses of azide as compared to control and 0.5% dose. However, cytogenetic assessment of the treated plants clearly revealed the preponderance of stickiness distributed in all the phases of meiotic division that persisted up to the tetrad stage. The phenomenon displayed mild to severe case of stickiness on the basis of number of genome involved during meiosis. Manifestation of stickiness has also been resulted in several other meiotic abnormalities such as bridge (1.88%), unorientation (0.64%), micronuclei (1.38%), asynchronous division (0.77%), and precocious chromosomes (3.89%) along with some other anomalies (laggards, univalents etc.). Frequency of these anomalies along with severe stickiness was higher at 0.5% dose of azide that must have compromised with pollen fertility resulting declined fertility rate. Though, pollen fertility at 0.3% and 0.7% doses had not been much affected and had fallen near control. Thus, from present investigation inference can be drawn that the sodium azide induced stickiness might have resulted in some meiotic mutant that has imposed some novel genetic combinations thereby positively affecting morphological traits of the crop.