Cytological Effect of Gamma Radiation on Selected Mutants of Wheat Triticum aestivum L. in M3 Generation.

Background and Objective: Wheat (Triticum aestivum L.) offers some unique opportunities for the induction and exploitation of agronomic value. The use of gamma radiation has been proven to be an effective method to induce genetic variation in crops. We aimed to determine genetically stable mutants of wheat which could be utilized for breeding purposes.
Materials and Methods: We did a cytological investigation of induced mutant's behavior and chiasma frequency. Selected mutant types induced in dry and soaked seeds were treated with different doses of gamma rays. Each treated sample and control were subjected to cytological examination of the fixed pollen mother cells in various meiotic stages.
Results: The percentage of the total abnormal cells significantly increased in one mutant and significantly decreased in the other mutant. The percentage of total abnormal cells did not diminish from the first to the second meiotic division. The types of meiotic anomalies found included laggards (56.51%), univalent (9.43%), stickiness (45.45%) and bridges (19.32%). There were genotypic differences in the frequency of occurrence of multivalent (trivalent and quadrivalents). A marked reduction in the number of rod and ring bivalent/cell in some genotypes were noticed. The frequency of chiasmata per pollen mother cell was reduced subsequently. Depression index of mutants was negative compared with controls or treatments except for a few genotypes.
Conclusion: Selected mutants of wheat tend to be cytologically stable and can therefore, be utilized for breeding purposes.