Salt Tolerance Of Wheat Genotypes Research Articles

Integrating Hyperspectral Reflectance-Based Phenotyping and SSR Marker-Based Genotyping for Assessing the Salt Tolerance of Wheat Genotypes under Real Field Conditions.

Wheat breeding programs are currently focusing on using non-destructive and cost-effective hyperspectral sensing tools to expeditiously and accurately phenotype large collections of genotypes. This approach is expected to accelerate the development of the abiotic stress tolerance of genotypes in breeding programs. This study aimed to assess salt tolerance in wheat genotypes using non-destructive canopy spectral reflectance measurements as an alternative to direct laborious and time-consuming phenological selection criteria. Eight wheat genotypes and sixteen F8 RILs were tested under 150 mM NaCl in real field conditions for two years. Fourteen spectral reflectance indices (SRIs) were calculated from the spectral data, including vegetation SRIs and water SRIs. The effectiveness of these indices in assessing salt tolerance was compared with four morpho-physiological traits using genetic parameters, SSR markers, the Mantel test, hierarchical clustering heatmaps, stepwise multiple linear regression, and principal component analysis (PCA). The results showed significant differences (p ≤ 0.001) among RILs/cultivars for both traits and SRIs. The heritability, genetic gain, and genotypic and phenotypic coefficients of variability for most SRIs were comparable to those of measured traits. The SRIs effectively differentiated between salt-tolerant and sensitive genotypes and exhibited strong correlations with SSR markers (R2 = 0.56-0.89), similar to the measured traits and allelic data of 34 SSRs. A strong correlation (r = 0.27, p < 0.0001) was found between the similarity coefficients of SRIs and SSR data, which was higher than that between measured traits and SSR data (r = 0.20, p < 0.0003) based on the Mantel test. The PCA indicated that all vegetation SRIs and most water SRIs were grouped with measured traits in a positive direction and effectively identified the salt-tolerant RILs/cultivars. The PLSR models, which were based on all SRIs, accurately and robustly estimated the various morpho-physiological traits compared to using individual SRIs. The study suggests that various SRIs can be integrated with PLSR in wheat breeding programs as a cost-effective and non-destructive tool for phenotyping and screening large wheat populations for salt tolerance in a short time frame. This approach can replace the need for traditional morpho-physiological traits and accelerate the development of salt-tolerant wheat genotypes.

Potential of Thermal and RGB Imaging Combined with Artificial Neural Networks for Assessing Salt Tolerance of Wheat Genotypes Grown in Real-Field Conditions

Developing new bread wheat varieties that can be successfully grown in saline conditions has become a pressing task for plant breeders. High-throughput phenotyping tools are crucial for this task. Proximal remote sensing is gaining popularity in breeding programs as a quick, cost-effective, and non-invasive tool to assess canopy structure and physiological traits in large genetic pools. Limited research has been conducted on the effectiveness of combining RGB and thermal imaging to assess the salt tolerance of different wheat genotypes. This study aimed to evaluate the effectiveness of combining several indices derived from thermal infrared and RGB images with artificial neural networks (ANNs) for assessing relative water content (RWC), chlorophyll a (Chla), chlorophyll b (Chlb), total chlorophyll (Chlt), and plant dry weight (PDW) of 18 recombinant inbred lines (RILs) and their 3 parents irrigated with saline water (150 mM NaCl). The results showed significant differences in various traits and indices among the tested genotypes. The normalized relative canopy temperature (NRCT) index exhibited strong correlations with RWC, Chla, Chlb, Chlt, and PDW, with R2 values ranging from 0.50 to 0.73, 0.53 to 0.76, 0.68 to 0.84, 0.68 to 0.84, and 0.52 to 0.76, respectively. Additionally, there was a strong relationship between several RGB indices and measured traits, with the highest R2 values reaching up to 0.70. The visible atmospherically resistant index (VARI), a popular index derived from RGB imaging, showed significant correlations with NRCT, RWC, Chla, Chlb, Chlt, and PDW, with R2 values ranging from 0.49 to 0.62 across two seasons. The different ANNs models demonstrated high predictive accuracy for NRCT and other measured traits, with R2 values ranging from 0.62 to 0.90 in the training dataset and from 0.46 to 0.68 in the cross-validation dataset. Thus, our study shows that integrating high-throughput digital image tools with ANN models can efficiently and non-invasively assess the salt tolerance of a large number of wheat genotypes in breeding programs.

TESTING OF WHEAT GENOTYPES FOR SALT TOLERANCE AND LEAF RUST DISEASE CAUSED BY PUCCINIA

Parameters that show a significant genotypic variation and are associated with salt tolerance may be used as rapid and economic screening criteria in breeding programs. The objective of this study was to test growth and yield components for evaluating the salt tolerance of wheat genotypes. Five genotypes of winter wheat (Triticum aestivum L.) were used in this study, that differ from their salt tolerance, which were grown in 28 dS/m saline soil, and irrigated by well water with a salinity 7.5 dS/m. The results showed that salt concentration in the soil was reduced with plant growth stages from 28 dS/m before sowing to 8, 7.5, and 7.6 dS/m for N1, N2, and N3 genotypes, respectively. Whereas approached 16 and 17 dS/m for Tumos2 and Mexipak, cultivars, respectively, at the maturity stage. Concerning germination percentage under saline conditions, wheat genotypes N1, N2, and N3 showed the highest percentages of 89, 90, and 90%, respectively, which was significantly different than wheat cultivars Tumos2 and Mexipak 79 and 83%, respectively. Statistical analysis of the data revealed that genotype N2 required a maximum days for germination 14 days, whereas cultivarTumos2 required less days for germination 12 days. For spikes formation duration growth the genotype N3 was the late 119 days, whereas for physiological maturity N1 genotype was the latest 153 days. The number of spikes per 6 m2, grains spike-1, and grain weight were reduced significantly in sensitive cultivars Tumos2 and Mexipak. Higher grain yield with N2 genotype 2739.43 g with no significant differences with the genotypes N1 and N2, and with significant differences with the rest sensitive cultivars Tumos2 and Mexipak 346.61 and 242.98 g, respectively. Therefore, we conclude that the measurements of growth and yield components may be effective criteria for screening wheat genotypes for salt tolerance. Moreover, N1, N2, and N3 genotypes were identified as the most salt-tolerant genotypes in this study, they can be utilized through appropriate selection and breeding programs for further improvement in salt tolerance of Iraqi wheat genotypes.

Integrating Agro-Morpho-Physiological Traits and SSR Markers for Detecting the Salt Tolerance of Advanced Spring Wheat Lines under Field Conditions

To successfully enhance the salt tolerance of genotypes, it is crucial to conduct field-based trials, establish effective screening criteria and analysis tools, evaluate salt tolerance at various growth stages, and integrate phenotypic assessment-based traits with molecular markers. This study aimed to assess the salt tolerance of 16 F8 recombinant inbred lines (RILs) and eight genotypes by analyzing 13 agro-morpho-physiological traits using various analysis tools and SSR markers under both control and high salinity levels (15 dS m−1) in real field conditions. Analysis of variance (ANOVA), comparison of mean values, calculation of reduction percentage, and multivariate analysis were used to compare the assessed traits among genotypes and identify which traits are the most effective ones in describing the salt tolerance of these genotypes. A heatmap cluster analysis (HMCA) was also employed to categorize the salt tolerance of genotypes into different clusters based on the stress tolerance index (STI) for all traits. The ANOVA results revealed significant statistical differences (p ≤ 0.05) between the genotypes and salinity levels for all assessed traits in each season and their combined data. Moreover, the 150 mM NaCl treatment led to decreases in the assessed traits by 10.2% to 36.9% when compared to the control treatments. Furthermore, the mean values of assessed traits for certain genotypes were approximately one to three times greater than those of other genotypes. Principal component analysis has identified plant dry weight, green leaf area, leaf area index, and grain yield per hectare as effective screening criteria for explaining the substantial variation observed among the genotypes. The HMCA successfully grouped genotypes into three distinct clusters and distinguished the salt-tolerant genotypes from the salt-sensitive and intermediate ones. The 24 genotypes/RILs were classified into three main groups according to the allelic data of 40 SSRs associated with salt-tolerant genes. A weak yet significant correlation was observed between the similarity coefficients of agro-morpho-physiological traits and SSR markers, as determined by the Mantel test (r = 0.13, p &lt; 0.03, and alpha = 0.05). In conclusion, this study has successfully identified several traits, particularly those associated with SSR markers, that greatly contribute to our understanding of the phenotypic and genotypic basis influencing the salt tolerance of wheat genotypes in real field conditions. Consequently, assessing these traits for a large number of wheat plant materials in a rapid and cost-effective manner will be greatly importance in breeding programs aimed at improving salt stress tolerance in this vital food crop. This will be the main focus of our forthcoming research.

Comparing the salinity tolerance of twenty different wheat genotypes on the basis of their physiological and biochemical parameters under NaCl stress.

The climate has drastically changed over the past two decades. Rising temperatures and climate change may lead to increased evapotranspiration, specifically soil evaporation, causing water to evaporate and salt to accumulate in the soil, resulting in increased soil salinity. As a result, there is a need to evaluate methods for predicting and monitoring the effects of salinity on crop growth and production through rapid screening. Our study was conducted on 20 wheat genotypes, 10 sensitive and 10 tolerant, exposed to two salinity levels (90 and 120 mM NaCl) with the control under greenhouse conditions. Our results revealed significant differences in the genotypes' response to salinity. Salt stress decreased chlorophyll index in sensitive genotypes but increased chlorophyll a and carotenoids in tolerant genotypes at 90 mM. Salt stress also increased protein, proline, lipoxygenase, and reactive thiobarbituric acid levels in all wheat genotypes. The study suggests that plant photosynthetic efficiency is a reliable, non-destructive biomarker for determining the salt tolerance of wheat genotypes, while other biochemical traits are destructive and time-consuming and therefore not suitable for rapid screening.

TAOPR1 SALT TOLERANCE GENE EXPRESSION AND PHYSIOLOGICAL TRAITS IN WHEAT

Salinity is an abiotic stress factor and a major challenge that has significant negative effects on wheat production. It is also a source of concern for plant breeders leading them to reach reliable screening criteria for salt tolerance in wheat genotypes. The physiological analysis showed that the three salt-tolerant wheat genotypes viz., Dijla, 2H, and 3H showed the highest rate for the physiological traits i.e., chlorophyll content (38.9, 39.5, and 42.1, respectively), carbohydrates (600.14, 590.6, 560.8: 2H, 3H, and Dijla, respectively), proline acid (24.30, 23.14, and 21.87: Dijla, 3H, and 2H, respectively) under salt stress conditions, except protein percentage (3.8% and 3.3%: Rabia and Ibaa99, respectively) and K+/Na+ ratio (6.3 and 5.9: 2H and Dijla, respectively). The salt-tolerant wheat genotypes 2H, Dijla, and 3H enunciated an increased rate of expression of salt-related genes (TaOPR1 gene and β-actin gene) with values of 6.498, 4.0, and 3.768, respectively compared to two other salinity-sensitive cultivars i.e., Ibaa99 and Rabia under salt stress conditions. The salinity-sensitive cultivars i.e., Ibaa99 and Rabia showed no gene expression and significant difference with the control treatment after being treated with salinity stress conditions.

Assessment of the salt tolerance of wheat genotypes during the germination stage based on germination ability parameters and associated SSR markers

ABSTRACT Although the germination stage accounts for a very short period of a plant’s life cycle, it involves numerous mechanisms and multistage processes that potentially differ among genotypes under salt stress. Therefore, we hypothesized that the parameters controlling the water uptake pattern and α-amylase activity during the seed germination process could be helpful for assessment the salt tolerance of wheat genotypes at the early growth stage. Genotypic differences in the germination ability parameters and α-amylase activity were assessed for seven wheat cultivars under normal and salt stress conditions at the molecular marker level using 30 simple sequence repeat (SSR) markers linked to salt tolerance. Results found that genotypic variations in the water uptake pattern were appeared at the late stage of phase II under both salinity levels and more obviously during phase III. Genotypic variations were observed in the germination time (GT), which was delayed by increasing salinity levels. The α-amylase activity and GT were positively and negatively correlated, respectively, with each time of water uptake rate. Significant correlation (r = 0.49, P = 0.026) was observed between similarity coefficients of germination ability parameters and SSR data based on the Mantel test. Among the 24 SSR markers, which showed polymorphism, Cdf 9, Cdf 46, Cdf 49, Wmc 503, and Gwm 312 were associated with almost germination ability parameters (R 2 ranged from 0.43 to 0.95). Therefore, based on the molecular marker-phenotypic trait association at germination stage, assessment of salt tolerance in many wheat genotypes in a relatively short time could be conceivable.

Biochemical indices and RAPD markers for salt tolerance in wheat genotypes

The present study examines ten wheat (5 Triticum aestivum, 4 T. durum, and 1 T. diccocum) genotypes for biochemical and RAPD markers associated with NaCl based salt tolerance capacity [T0 (control), T1 (50 mM NaCl), T2 (100 mM NaCl) and T3 (150 mM NaCl)]. The highest STI was obtained with four tolerant KH-65 (81.32), KRL-213 (81.24), DDK-1025 (80.70), and HI-8498 (80.00) wheat genotypes. The free proline was positively correlated with STI, followed by free amino acids and total sugars, suggesting their roles as osmolytes to overcome the salt stress in wheat genotypes. The RAPD analysis of wheat genotypes carried out with twenty-two RAPD primers generated a total of 129 alleles out of which 90 bands were polymorphic with an average of 4.09 bands and 65.1 % polymorphism per primer. The unique and genotype specific markers were obtained by eight RAPD primers. The phylogenetic analysis of wheat genotypes showed a Jaccard similarity coefficient in the range of 0.64–0.78. Clustering pattern of wheat genotype indicated four salt tolerant genotypes (one Triticum aestivum, two T. durum, one T. diccocum) grouped into one cluster and shared minimum (64 %) similarity with each other. The most tolerant two wheat genotypes KH-65 (T. aestivum) and KRL-213 (T. durum) were grouped together and shared maximum (78 %) similarity each other. The maximum five unique bands were found to discriminate salt tolerant KRL-213 and further characterization of salinity tolerant trait in wheat genotypes.

Investigation of the Salt Tolerance of Wheat Genotypes: Changes in Antioxidants, Total Protein, K+/Na+ Ions and Grain Yield

Investigation of the Salt Tolerance of Wheat Genotypes: Changes in Antioxidants, Total Protein, K+/Na+ Ions and Grain Yield

Microsatellite Markers Based Genetic Diversity Analysis for Salt Tolerance in Wheat Genotypes

Wheat genotypes (five Triticum aestivum, four T. durum, one T. diccocum) were studied for salt tolerance capacity [T0 (control), T1(50 mM NaCl), T2(100 mM NaCl) and T3(150 mM NaCl)] on the basis of physiological [relative water content (RWC), membrane stability index (MSI) and salt tolerant index (STI)] parameters and microsatellite markers. The physiological parameters were positively correlated with salt tolerant index (STI). The high STI was shown in four tolerant genotypes namely KH-65 (81.32), DDK-1025 (80.70), HI-8498 (80.00) and KRL-213 (81.24), respectively. The SSR analysis of the wheat genotypes was carried out with SSR primers using generated total of 74 alleles out of which 59 were polymorphic with an average of 4.21 alleles and 80.25% polymorphism per primer. The unique and genotype specific markers were obtained by four SSR primers. The salt tolerant DDK-1025 diagnosed with unique Xgwm-146183 marker. The phylogenetic analysis of wheat genotypes showed Jaccard similarity coefficient in the range of 0.37 to 0.79. Clustering pattern of wheat genotype out grouped most tolerant KH-65 from other nine genotypes and shared minimum 37% similarity.

English

&nbsp; Soil salinity is a serious threat in many parts of the world in general and of Tunisia in particular, which negatively affects plant production. In this experiment, response of durum wheat to salinity in seven genotypes namely; four local cultivars (Azizi, Jenah Khotifa, Hmira and Sweb&acirc;a Eljia), two improved varieties (Karim and Om Rabia) and an algerian cultivar (Oued Zeneti)] to salinity (0 and 100 mM of NaCl) was investigated in hydroponic conditions. Salinity induced no effects in all genotypes on the maximal efficiency of PSII (Fv/Fm) photochemistry. The Fv/Fm&nbsp;showed that Jenah Khotifa and Karim were the most tolerant genotypes under saline conditions (100 mM of NaCl). This may be associated with higher chlorophyll (a and b) contents. Results also depicted that all genotypes showed higher content proline as well as lower sodium content as compared with Jenah Khotifa with a reduction of 68.53% under 100 mM NaCl.&nbsp;It was concluded that high chlorophyll content and the proline accumulation in plant will improve the salt tolerance of wheat genotypes in breeding programs. &nbsp; Key words:&nbsp;Durum wheat, salt stress, genotypic variation, seedling stage.

Screening Egyptian Wheat Genotypes for Salt Tolerance at Early Growth Stages

Parameters that show a significant genotypic variation at early growth stages and are associated with salt tolerance at later stages may be used as rapid and economic screening criteria in breeding programs. The objective of this study was to test growth parameters at early growth stages for evaluating the salt tolerance of wheat genotypes. Ten wheat genotypes that differ from their salt tolerance were grown in soil and exposed to four salinity concentrations (0, 40, 80 and 160 mM NaCl). Germination percentage was recorded daily up to 8 days. Seedling growth parameters (i.e. shoot height, dry weight of shoots and roots and root/shoot ratio) were determined at day 14 after sowing. The results showed that salinity did not affect final germination percentage, while seeds subjected to 80 and 160 mM NaCl retarded germination by 1 and 2 days, respectively, as compared with 0 mM NaCl treatment. Salinity affected shoot growth more severely than root growth of seedlings. Importantly, height and dry weight of shoot ranked genotypes in the same order as their salt-tolerance rankings in terms of grain yield, whereas root dry weight did not. Therefore, we conclude that the measurements of shoot growth may be effective criteria for screening wheat genotypes for salt tolerance at early growth stages.

Contrasting leaf Na+ uptake and transport rates conferred differences in salt tolerance of wheat genotypes

The genotypic differences regarding Na+ accumulation and transport in plants along with the physiological response to improve salt tolerance were studied in bread wheat genotypes. Four wheat genotypes; Kharchia-65, SARC-3, S-9476, and S-8189 were grown under salt stress (75 and 150 mM NaCl) in nutrient solution with five replications. Shoot dry weight, relative growth rate (RGR), chlorophyll index, leaf water relations, Na+ content, and transport in plants were measured. The increase in NaCl stress decreased all growth parameters; however, variations were observed among genotypes. Kharchia-65, S-9476, and SARC-3 had better growth and water relations compared with the salt-sensitive genotype S-8189. The low rate of Na+ transport and better ability to restrict Na+ in the root was the main reason for genetic variation among different genotypes, especially when growth characteristics did not vary significantly under salt stress. Na+ partition was also recorded in the wheat genotypes, since salt-sensitive genotypes had higher Na+ accumulation in shoot while this was reversed in tolerant ones. The differences in root Na+ were not significant among all genotypes.

Evaluating salt tolerance of wheat genotypes using multiple parameters

Salt tolerance of wheat is known to change with growth stage. Identifying the multiple parameters associated with salt tolerance during different growth stages is important for evaluating wheat genotypes and improving their salt tolerance. Thirteen wheat genotypes from Egypt, Germany, Australia and India were grown in soil and exposed to four salinity levels (control, 50, 100 and 150 mM NaCl). Tiller number, leaf number and leaf area per plant at vegetative stage; dry weight per plant at vegetative, reproductive and maturity stages; and yield components of main spike and total grain yield at maturity were determined. The results showed that tiller number was affected more by salinity than leaf number and leaf area at the vegetative stage. Salinity decreased dry weight per plant significantly at all growth stages. Spikelet number on the main stem decreased much more with salinity than spike length, grain number and 1000-grain weight at maturity. According to cluster analysis with multiple agronomic parameters at all growth stages, the Egyptian genotypes Sakha 8 and Sakha 93 and the Indian genotype Kharchia were ranked as the most tolerant to salinity. A change in salt tolerance with growth stages was observed for Sids 1, Gemmeza 7 and Westonia. Drysdale and Sakha 69 were ranked as moderate tolerant. The remaining genotypes showed the lowest tolerance to salinity at all growth stages. We conclude that an increase in tiller number per plant and spikelet number per spike will improve the salt tolerance of wheat genotypes in breeding programs. Cluster analysis with multiple agronomic parameters simultaneously to evaluate the salt tolerance facilitates the rankings of salt tolerance of wheat genotypes.

Effects of various salt concentrations on germination of seeds and morphometric parameters of diploid wheat seedlings

Aim. The aim of the research was the assessment of salt-tolerance of diploid wheat genotypes Triticum monococcum and Triticum dicoccum at the grain germination stage. Methods. To determine morphometric parameters of salt tolerance of wheat varieties, seeds were germinated in a NaCl solution and in distilled water using the roll method. Screening for salt tolerance of wheat genotypes was conducted at 100, 150 and 200 mM concentrations of NaCl. Seeds were kept on wet filter paper, at 20–22 ℃ temperature, in the dark for 3 days and then germinated under 12h/12h (light/dark) photoperiod for 7 days. Results. Germination energy for Tr. monococcum was 85–50 % and for Tr. dicoccum 85–70 % under salinity. Growth dynamics of the root system of diploid wheat genotypes during 10 days showed that the growth rate declined with increasing salt concentrations, and this decline was different in the genotypes. Conclusions. The results suggest that according to the characteristics of salt tolerance of diploid wheat varieties at the germination stage Tr. monococcum is a sensitive and Tr. dicoccum, which manifested relatively high parameters, is a tolerant variety.&#x0D; Keywords: wheat genotypes, Triticum monococcum, Triticum dicoccum, salt stress, germination.