Barley is a very important crop worldwide and has good impact in preserving food security. The impacts of 10 mM proline and 0.5 mM salicylic acid were evaluated on water stressed barley plants (Hordeum vulgare L. Giza126). Salicylic acid and proline treatments led to increased stem length, plant dry weights, chlorophyll concentration, relative water content, activity of antioxidant enzymes, and grain yield under drought stress. Nevertheless, lipid peroxidation, electrolyte leakage (EL), superoxide (O2·−), and hydrogen peroxide (H2O2) significantly decreased in treated barley plants with proline and salicylic acid in both growing seasons as compared with drought treatment only, which caused significant decrease in stem length, plant dry weights, chlorophyll concentration, activity of antioxidant enzymes, as well as biological and grain yield. These results demonstrated the importance of salicylic acid and proline as tolerance inducers of drought stress in barley plants.

The impact of biochar and chitosan on barley plants under drought stress conditions was investigated during two field experiments. Our results confirmed that drought stress negatively affected morphological and physiological growth traits of barley plants such as plant height, number of leaves, chlorophyll concentrations, and relative water content. However, electrolyte leakage (EL%), lipid peroxidation (MDA), soluble sugars, sucrose and starch contents significantly increased as a response to drought stress. Additionally, 1000 grain weight, grains yield ha−1 and biological yield significantly decreased in stressed barley plants, also anatomical traits such as upper epidermis, lower epidermis, lamina, and mesophyll tissue thickness as well as vascular bundle diameter of flag leaves significantly decreased compared with control. The use of biochar and chitosan led to significant increases in plant height, number of leaves, and chlorophyll concentrations as well as relative water content; nevertheless these treatments led to significant decreases in electrolyte leakage (EL%) and lipid peroxidation (MDA) in the stressed plants. Moreover, anatomical and yield characters of stressed barley plants were improved with application of biochar and chitosan. The results proved the significance of biochar and chitosan in alleviating the damaging impacts of drought on barley plants.

Quinoa cultivation has expanded from South America to many countries because of its wide adaptability and nutritional value. We evaluated 32 introduced quinoa genotypes using 17 qualitative and 11 quantitative traits under Saudi Arabia conditions during the 2018–2019 season. The quinoa genotypes showed considerable variation during the vegetative and maturity stages. Plant height values varied between 60 and 18 cm, and maturity ranged from 98 to 177 days. Leaf shapes were rhomboidal or triangular, with dentate or serrate margins. Green was the standard color for leaves and panicles at the flowering stage. The leaf granule colors were white, purple, and white-red. At 150 units of the Euclidean distance, the genotypes aggregated into four major groups based on their morphological traits. Twenty-one sequence-related amplified polymorphism (SRAP) primer pair combinations generated 75 amplified fragments (alleles), with a mean of 3.57 alleles per primer pair combination. Unweighted Pair-Group Method with Arithmetic means (UPGMA) clustering analysis showed that the quinoa genotypes were grouped based on origin or according to genetic background. Genotypes from South America presented higher mean values for the average number of alleles, Shannon index (0.411), gene diversity (0.271), and polymorphic percentage (83.95). Analysis of molecular variance (AMOVA) showed that most of the genetic variation was because of differences within populations (86%). The wide variability of the genotypes studied herein is of great importance for quinoa breeders.

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Hybrid performance during wheat breeding can be improved by analyzing genetic distance (GD) among wheat genotypes and determining its correlation with heterosis. This study evaluated the GD between 16 wheat genotypes by using 60 simple sequence repeat (SSR) markers to classify them according to their relationships and select those with greater genetic diversity, evaluate the correlation of the SSR marker distance with heterotic performance and specific combining ability (SCA) for heat stress tolerance, and identify traits that most influence grain yield (GY). Eight parental genotypes with greater genetic diversity and their 28 F 1 hybrids generated using diallel crossing were evaluated for 12 measured traits in two seasons. The GD varied from 0.235 to 0.911 across the 16 genotypes. Cluster analysis based on the GD estimated using SSRs classified the genotypes into three major groups and six subgroups , almost consistent with the results of principal coordinate analysis. The combined data indicated that five hybrids showed 20% greater yield than mid-parent or better-parent. Two hybrids (P2 × P4) and (P2 × P5), which showed the highest performance of days to heading (DH), grain filling duration (GFD), and GY, and had large genetic diversity among themselves (0.883 and 0.911, respectively), were deemed as promising heat-tolerant hybrids. They showed the best mid-parent heterosis and better-parent heterosis (BPH) for DH (-11.57 and-7.65%;-13.39 and-8.36%, respectively), GFD (12.74 and 12.17%; 12.09 and 10.59%, respectively), and GY (36.04 and 20.04%; 44.06 and 37.73%, respectively). Correlation between GD and each of BPH and SCA effects based on SSR markers was significantly positive for GFD, hundred kernel weight, number of kernels per spike, harvest index, GY, and grain filling rate and was significantly negative for DH. These correlations indicate that the performance of wheat hybrids with high GY and earliness could be predicted by determining the GD of the parents by using SSR markers. Multivariate analysis (stepwise regression and path coefficient) suggested that GFD, hundred kernel weight, days to maturity, and number of kernels per spike had the highest influence on GY.

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.

Salinity is one of the largest stresses blocking horizontal and vertical expansion in agricultural lands. Establishing salt-tolerant genotypes is a promising method to benefit from poor water quality and salinized lands. An integrated method was developed for accomplishing reliable and effective evaluation of traits stability of salt-tolerant wheat. The study aims were to estimate the genetic relationships between explanatory traits and shoot dry matter (SDM), and determine the traits stability under three salinity levels. Morphophysiological and biochemical traits were evaluated as selection criteria for SDM improvement in wheat for salinity tolerance. Three cultivars and three high-yielding doubled haploid lines (DHLs) were used. Three salt (NaCl) levels (control (washed sand), 7 and 14 dS m −1 ) were applied for 45 days (at the first signs of death in the sensitive genotypes). All morphophysiological traits gradually decreased as salinity levels increased, excluding the number of roots. Decreases were more visible in sensitive genotypes than in tolerant genotypes. All biochemical traits increased as salinity levels increased. Variance inflation factors (VIFs) and condition number exhibited multicollinearity for membrane stability index and polyphenol oxidase activity. After their removal, all VIFs were <10, thereby increasing path coefficient accuracy. Total chlorophyll content (CHL) and catalase (CAT) provided significant direct effects regarding genetic and phenotypic correlations for the three salinity levels and their interactions in path analysis on SDM, indicating their stability. CHL and CAT had high heritability (>0.60%) and genetic gain (>20%) and highly significant genetic correlation, co-heritability, and selection efficiencies for SDM. CHL and CAT could be used as selection criteria for salinity tolerance in wheat-breeding programs. The tolerated line (DHL21) with the check cultivar (Sakha 93) can be also recommended as novel genetic resource for improving salinity tolerance of wheat.

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