Cytological Assessment of Gamma Induced Multiple Translocation Heterozygote in Sowa (Anethum graveolens L.)

Abstract

In this experiment the development of the various chromosomal interchanges in Sowa (Anethum graveolens L.) was accomplished with the help of Gamma irradiations. The pollen mother cells of Anethum graveolens were observed to be perfectly normal in untreated plants and displayed a regular formation of eleven bivalents at diakinesis, followed by normal separation (11:11) at anaphase I. Cytological manifestation of chromosome configurations at diakinesis and metaphase-I exhibited translocation heterozygotes by the formation of either ring or chain of chromosomes in PMCs of Sowa, particularly at higher doses of Gamma irradiation (200 Gy). The translocation lines showed discernible prevalence of rings (56.58%) over chains (43.42%). In chromosomal configuration, PMCs of Irradiated plants, shows the presence of minimum one or more quadrivalent and bivalents, besides this, some PMCs showed other configurations such as trivalents, pentavalents, hexavalent, and octavalent along with variable number of univalents. At diakinesis, stage of PMCs, 2_III + 1_IX + 2_IV + 1_II + 1_I configuration was observed in maximum (12.88%) followed by 6_II + 1_IV + 1_V + 1_I (12.37%) and 1_VII + 1_V + 2_IV + 2_I (11.85%). The configuration 1_X + 2_IV + 2_II showed the lowest (5.15%) frequency. However, a variety of anomalies such as unequal separation (34.93%), laggards (21.91%) and bridges (12.32%) were also recorded. Pollen fertility was reduced (41.21 ± 0.19%) in translocation lines as comparison to control plant (98.59 ± 0.25%). Translocation heterozygotes might be used as an initial foundation for developing aneuploids with novel gene combinations.