Molecular evaluation of salt tolerance induced by sodium azide in immature embryos of two wheat cultivars

Background: The artificial induction of mutations represents an efficient tool in creating genetic variations. For this reason, the current study was carried out in the Plant Tissue Culture Laboratory/Genetic Engineering Institute to induce genetic diversity for salt tolerance in two local cultivars of bread wheat (Al-Iraq and Tamooz 2) using in vitro application of sodium azide (SA). Objective: Immature seeds from both cultivars subjected to 0, 0.5, 1.0 and 2.0 Mm of SA to determine the optimal concentration for developing novel mutants. Materials and methods: The optimal dose of SA mutagen was found to be 2.0 mM, resulting in a 42% reduction in callus fresh and dry weight. The developed callus was subjected to five different salinity levels using NaCl (6, 8, 10, 12 and 14 dS m-1). Results: Mutants showed a significant decrease in the percentage of regenerated plants under salinity stress conditions. The used SSR markers approved the genetic diversity between the original and the mutants of the two cultivars (Al-Iraq and Tamooz 2) growing under normal and salinity stress. The presences and the absence of some fragments was prominent in plants derived from immature embryos of the two cultivars tested in salinity conditions. The used SSR markers (cfd 9, cfd4, cfd1 wmc405, PYL5, HKT1, HVA1 and htk1) were so efficient in distinguishing between the original and tissue culture-derived plants. Furthermore, the experienced SA levels induced a higher rate of mutant alleles in cv. Conclusion: Al-Iraq with 19 mutant alleles than Tamooz 2 which showed only 13 mutant alleles. The current study represents an additional prove to the effectiveness of mutagens and tissue culture technique in developing novel variants with improved performance under stress conditions.