Morphological, Chemical and Molecular Evaluations For Several Rice (Oryza Sativa L.) Races Grown Under Salt Stress Levels

Abstract

A field experiment was carried out at the Agricultural Research and Experiments Station of the College of Agriculture, Al-Muthanna University during the summer season 2020. Pots of 15 cm diameter were used for planting the genotypes, with (SS, F-RCBD) and three replications. Ten different genotypes rice were used (FRI, FR2, FR15, FR16, FR17, FR18, FR21, FR25, FR27), as well as the rice varieties, which are Pokkali, Anber-33 and Jasmine, were irrigated by three levels of salty water (4.5, 7.5 and 15 ds/m). The results of the experiment showed that the tolerance of the genotypes FR21 and FR12 to salinity was associated with containing low concentrations of sodium (0.38 and 0.42%) respectively in the shoot, and a high concentration of potassium in the shoot (1.22 and 1.23%) respectively, and this result was reflected in the ratio of potassium to sodium in the shoot total was (3.30 and 2.95%) compared to the salt-tolerant variety Pokkali. Salinity caused a significant decrease in all the studied traits of the genotypes, especially at levels 7.5 and 15 ds/m, in growth traits (plant height, flag leaf area and panicle length), yield and its components (number of productive tillers, weight of 1000 grains and yield per plant). The most potent varieties in salt tolerance were FR12 and FR21, as they gave the highest yield of grains (11.72 and 16.67 g/plant, respectively), flag leave area (30.47 and 27.76 cm2 respectively). Detection for OsHKT4 and OsHKT6 by PCR proved the presence of primary locus that utilized by each gene with successfully fused genes as well as their stability under Iraqi cultivation circumstances, particularly in the case of FR12 and FR21 where OsHKT4 lanes were very obvious (2840 Kb) and the bands of OsHKT6 at (2324 Kb), which resemble to that in Pokkali Japanese salt tolerance rice. These results suggested the variation among investigated rice varieties in their tolerance to salts, where FR12 and FR21 were best in their performance under applied the salt levels conditions.