Comparative Analysis of Different Chemical Mutagens in Inducing Chromosomal Aberrations in Meiotic Cells of Triticum aestivum L.

Abstract

Chromosomal aberration assessment is an important index in mutation breeding for determining the mutagen potency, which helps to deduce an optimum level of mutagen dose tolerable by the species. In this study, the genotoxic effects of ethyl methane sulphonate (EMS), methyl methane sulphonate (MMS) sodium azide (SA), and colchicine were studied on the meiotic cell division of Triticum aestivum L. The results demonstrated that these chemical mutagens cause various types of meiotic anomalies, such as univalents, multivalents, chromosome stickiness, unoriented chromosomes, precocious chromosome movements, chromatin bridges, lagging chromosomes, acentric fragments, and micronuclei. A substantial influence of chromosomal aberrations on the post-meiotic product was also experienced. Irregular sporads in the form of triads, dyads, monads, and polyads, along with regular tetrads were witnessed. The maximum chromosomal aberrations were observed at higher concentrations of the mutagenic treatments. The highest proportion of pollen mother cells showing meiotic aberrations was induced by EMS followed by colchicine, MMS, and SA. The frequency of fertile pollens was seen to decline from control to the highest concentration of mutagens due to anomalies of preceding stages. In addition, mutagenic treatments decreased germination and survival percentage as well. The treatment concentrations ranging from 0.2–0.3% were found favorable in creating significant cytogenetic variability and average lethality and thus, could be beneficial in future cytological and mutation breeding programs.