INDUCTION OF GENETIC VARIATIONS IN TWO GENOTYPES OF RICE (ORYZA SATIVA L.) USING SODIUM AZIDE UNDER DIFFERENT SALINITY LEVELS.

The field experiment was conducted at the rice research station in Al- Mashkhab (Al-Najaf Governorate) during the 2021 season. Two rice genotypes (V1 and V3) were treated with two concentrations of sodium azide. The induced genotypes, in addition to the amber cultivar, were irrigated with different concentrations of NaCl, which included control (river water), 100 and 150 mmol NaCl. The objectives of the study were (1) to induce genetic variations for salt tolerance, (2) to evaluate the effect of sodium chloride on some agricultural traits and grain yield for the studied genotypes and (3) quantification of gene expression of the OsCIPK15 gene. Irrigation with different salinity concentrations negatively affected most of the studied traits compared to river water. Sodium azide generated genetic differences in some traits, as it reduced DTF, plant height, number of spikes, number of grains/spike, yield of grains/plant, while it had no significant effect on the weight of 1000 grain . Treatment with sodium azide also improved the salinity tolerance of V1 and V3 genotypes. With the increase of salinity levels of irrigation water, the gene expression of both the sodium azide-treated and untreated (V1 & V3) genotypes increased, while the gene expression of the amber cultivar decreased. Sodium azide-treated genotypes outperformed their non-treated counterparts in the rate of gene expression, which indicates sodium azide induction of the OsCIPK15 gene responsible for transduction of the signalling cascade in response to salinity stress.