Salinity is a major obstacle to wheat production worldwide. Salt-affected soils could be used by improving salt-tolerant genotypes depending upon the genetic variation and salt stress response of adapted and donor wheat germplasm. We used a comprehensive set of morpho-physiological and biochemical parameters and simple sequence repeat (SSR) marker technique with multivariate analysis to accurately demonstrate the phenotypic and genetic variation of 18 wheat genotypes under salinity stress. All genotypes were evaluated without NaCl as a control and with 150 mM NaCl, until the onset of symptoms of death in the sensitive plant (after 43 days of salinity treatment). The results showed that the relative change of the genetic variation was high for all parameters, heritability (>60%), and genetic gain (>20%). Stepwise regression analysis, noting the importance of the root dry matter, relative turgidity, and their respective contributions to the shoot dry matter, indicated their relevance in improving and evaluating the salt-tolerant genotypes of breeding programs. The relative change of the genotypes in terms of the relative turgidity and shoot dry matter during salt stress was verified using clustering methods. For cluster analysis, the genotypes were classified into three groups: tolerant, intermediate, and sensitive, representing five, six, and seven genotypes, respectively. The morphological and genetic distances were significantly correlated based on the Mantel test. Of the 23 SSR markers that showed polymorphism, 17 were associated with almost all examined parameters. Therefore, based on the observed molecular marker-phenotypic trait association, the markers were highly useful in detecting tolerant and sensitive genotypes. Thus, it considers a helpful tool for salt tolerance through marker-assisted selection.

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Salinity majorly hinders horizontal and vertical expansion in worldwide wheat production. Productivity can be enhanced using salt-tolerant wheat genotypes. However, the assessment of salt tolerance potential in bread wheat doubled haploid lines (DHL) through agro-physiological traits and stress-related gene expression analysis could potentially minimize the cost of breeding programs and be a powerful way for the selection of the most salt-tolerant genotype. We used an extensive set of agro-physiologic parameters and salt-stress-related gene expressions. Multivariate analysis was used to detect phenotypic and genetic variations of wheat genotypes more closely under salinity stress, and we analyzed how these strategies effectively balance each other. Four doubled haploid lines (DHLs) and the check cultivar (Sakha93) were evaluated in two salinity levels (without and 150 mM NaCl) until harvest. The five genotypes showed reduced growth under 150 mM NaCl; however, the check cultivar (Sakha93) died at the beginning of the flowering stage. Salt stress induced reduction traits, except the canopy temperature and initial electrical conductivity, which was found in each of the five genotypes, with the greatest decline occurring in the check cultivar (Sakha-93) and the least decline in DHL2. The genotypes DHL21 and DHL5 exhibited increased expression rate of salt-stress-related genes (TaNHX1, TaHKT1, and TaCAT1) compared with DHL2 and Sakha93 under salt stress conditions. Principle component analysis detection of the first two components explains 70.78% of the overall variation of all traits (28 out of 32 traits). A multiple linear regression model and path coefficient analysis showed a coefficient of determination (R2) of 0.93. The models identified two interpretive variables, number of spikelets, and/or number of kernels, which can be unbiased traits for assessing wheat DHLs under salinity stress conditions, given their contribution and direct impact on the grain yield.

Eight parents of bread wheat (Triticum aestivum , L.) illustrate a wide range of diversity for some agronomic traits were selected for the study namely; Gemmiza 11, Giza 168, Sids 14, Masr 2, Sids 12, Sakha 95, Masr 1 and Sakha 94 were crossed at 2016/2017 growing season in one direction diallel cross . The genetic analysis (variance, combining ability, heterosis, and type of gene actions) of grain yield / plant and some related traits were evaluated at 2017/2018. Results indicated that variances of genotypes, parents and crosses were highly significant for all evaluated traits. The variances connected to general and specific combining abilities were established be highly significant for all evaluated traits, except number of kernels /spike for GCA .The estimates of GCA/SCA were less than unity recommended the greater amount of non-additive gene actions in determining the performance of all traits. The crosses (P 1 xP 2 ), (P 2 xP 6 ); (P 3 xP 5 ), (P 3 xP 6 ) and (P 5 xP 6 ) recorded greatest mean values for grain yield/plant.P6 and P8 were considered as the best general combiners for grain yield /plant . The best crosses for SCA and heterosis effect for grain yield / plant recorded for P 1 xP 2 , P 3 xP 8 and P 5 xP 6 where be revealed highly significant and positive SCA and high percent heterosis making them hybrid promising in breeding programs for crop improvement . Hayman and Morley -Jones testing showed that the ratio of (H 1 /D) 1/2 is larger than one for all the studied traits, so over dominance is participating in the genetic of these traits .Estimates of percentage of negative and positive genes (H 2 /4H 1 ) in the parents ranged from 0.18 for plant height to 0.23 for number of kernels /spike and grain yield /plant hence, negative and positive alleles are consistent distributed in this traits. Heritability in broad-sense were high values detected for all the studied traits, indicated that these traits are more genetic, while narrow sense heritability were low for no. of spikes/plant, spike length and grain yield / plant , so the role of additive part is low. Significant differences were observe for additive ("a") effect for all the studied traits in Morley Jones method, Also , dominance ("b") part was significant for all the studied traits, appropriately these traits are controlled by both dominance and additive type of gene actions. As (b 2 ) and (b 3 ) were highly significant for all the studied traits, thus epistasis is participating in their genetics. As the part (b 1 ) was significant for all the evaluated traits, with the exception of plant height and 1000-kernel weight, so dominance genes were attributable to directional dominance. Significant (b 2 ) part for all traits showing imbalance of gene giving out for these traits. Significant (b 3 ) part for all traits showed residual dominance effect (b 3

The ac behavior of a nanocrystallite lead magnesium niobate (PMN) ceramic sample was studied over a wide range of temperatures and frequencies. The results revealed a diffuse phase transition and very high dielectric constant at lower frequencies. The high value of the dielectric constant at lower frequencies is shown to be due to barrier layer formation. A positive temperature coefficient of resistivity (PTCR) was observed in the temperature dependence of the ceramic resistivity. The results are explained on the basis of the Heywang and Jonker models. The Schottky barrier formed at grain boundary regions acts as a trap for the electrons available from oxygen vacancies in the ceramics. This provides PTCR characteristics from the transition temperature to about 208 C.

The current study was executed at the Experimental Farm, Faculty of Agriculture, Al-

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