Effect of B-chromosomes on meiotic behaviour and genetic recombination in Artemisia nilagirica (C. B. Clarke) Pamp.
2012 年 7 巻 1 号 p. 9-12
詳細
2012 年 7 巻 1 号 p. 9-12
The cytological studies revealed a population of Artemisia nilagirica (C. B. Clarke) Pamp. from Sirmaur, Himachal Pradesh, India was found to be diploid (2n=18) with 0-4B chromosomes. The number of Bs was almost fixed to 4 and found in 84.44% cells. The B-chromosomes showed regular bivalent formation in most of the PMCs. In spite of these, meiotic course analysis showed the presence of various irregularities in the form of laggards, bridges, cytomixis, and failure of cytokinesis, which resulted in formation of monads, dyads, triads and micronuclei imparting overal 17% abnormality. Analysis of chiasma frequency revealed that cells without Bs showed more chiasma frequency (14.06) as compared to cells with Bs (9.2-13.73). Pollen fertility was found to be quite high (96%). Presence of B-chromnosomes and other meiotic anomalies had no impact on pollen fertility.
