Evaluation of Bread Wheat Genotypes (Triticum aestivum L.) Response to Salinity Stress

In a greenhouse experiment the effects of salinity stress on fifteen bread wheat genotypes were evaluated, experimental factorial design was in a completely randomized block with four replications. Seed of the bread wheat genotypes sown in thoroughly washed sand in plastic containers. The sand was irrigated on alternative days with full strength Hoagland’s nutrient solution prepared in distilled water. Control and salinity treatment contains full strength Hoagland’s with 0 and 150 mM NaCl, respectively. Kharchia-66 and Chinese spring were tow of selected bread wheat genotypes as tolerant and susceptible control respectively. Other genotypes include double haploid lines that obtain from maize and wheat crosses as follow: DH-1557-1, DH-1557-3, DH-1557-7, DH-1557-15, DH-1557-33, DH-1102-12 and three Onfarm genotypes consist of Onfarm-4, Onfarm-6 and Onfarm9. The result showed that tolerant and susceptible bread wheat genotypes as regards to absorbance of sodium and potassium have genetic variability. The positive and significant correlation observed between K+/Na+ ratio and grain filling duration and seed dry weight. Salinity stress had no effects on flowering time. Salinity stress cause reduction of grain filling period and this reduction were greater in susceptible genotypes. Cluster analysis divided genotypes in four groups. SSI was considered to separate relative tolerance from absolute tolerance. Mahooti cultivar and DH-1557-3 double haploid line superior from other genotypes in view of stress susceptibility index of grain and shoot dry weight that indicate accumulation tolerant genes in two genotypes and Ghods cultivar and DH-1102-12 double haploid line inferior from other genotypes in view of stress susceptibility index. The result also indicated that the relative tolerance to salinity stress was highest in Roshan cultivar and among Onfarm lines the highest relative tolerance observed in Onfarm-6 line.