Salt-tolerant Genotypes Research Articles

Retrotransposon insertion variations in doubled haploid bread wheat mutants

The current study attempted to obtain candidate doubled haploid (DH) wheat lines by serially combining two approaches: conventional chemical mutagenesis and anther culture. Additionally, the salt tolerance levels were examined between stress-treated (100 mM NaCl) and non-treated DH groups. For the molecular analysis, IRAP markers were used to characterize retrotransposon insertion polymorphisms induced by haploidization, chromosome doubling, and/or mutagenesis in the DH lines. Various sodium azide (NaN3) concentrations (from 0 to 5 mM) were applied to seeds of the Pehlivan wheat cultivar to obtain an M1 generation mutant population. Anther culture was set up from the M1 mutant population. Green plant regeneration, the frequency of selected candidate mutants within the DH form and the levels of salt tolerance between samples were screened. A total of eight thousand anthers were cultured, and sixteen candidate salt-tolerant DH mutant lines, twenty-seven candidate DH mutant lines with different characteristics and one hundred and two candidate DH lines with morphologically normal appearances were obtained from the NaN3-mutagenized population. The IRAP patterns were quite similar between the control DH lines, and the genetic differences between the controls and DHs originating from possible mutants showed close relatedness. According to previous studies, chemical mutagenesis and anther culture were combined for the first time to detect candidate salt tolerant genotypes at the DH stage. This approach might also be useful for determining the threshold dose and efficiency of wheat mutagens.

Effectiveness of potassium in mitigating the salt-induced oxidative stress in contrasting tomato genotypes

ABSTRACTTo check the efficacy of potassium in alleviating oxidative stress under salt stress, salt-tolerant (Indent-1) and salt-sensitive (Red Ball) tomato (Lycopersicon esculentum Mill.) genotypes were exposed to three levels of sodium chloride (NaCl) (0, 75, 150 mM) and two levels of potassium (4.5 and 9 mM) in solution and foliar form. Thirty days of treatments revealed that increasing NaCl stress increased lipid peroxidation (malondialdehyde, MDA) and correspondingly the activity of antioxidant enzymes (superoxide dismutase, SOD; catalase, CAT; and glutathione reductase GR) in both genotypes. However, higher potassium (K) level in solution or foliar spray during the salt-induced stress decreased MDA and antioxidant activity and increased the growth in salt-tolerant genotype than in the salt-sensitive genotype. Decrease in MDA concentration, activity of antioxidant enzymes, and increase in the growth of tomato plants by the application of potassium under salt stress suggest that potassium is an effective ameliorating agent against salt-induced oxidative damage.

Silent S-Type Anion Channel Subunit SLAH1 Gates SLAH3 Open for Chloride Root-to-Shoot Translocation

Higher plants take up nutrients via the roots and load them into xylem vessels for translocation to the shoot. After uptake, anions have to be channeled toward the root xylem vessels. Thereby, xylem parenchyma and pericycle cells control the anion composition of the root-shoot xylem sap [1-6]. The fact that salt-tolerant genotypes possess lower xylem-sap Cl(-) contents compared to salt-sensitive genotypes [7-10] indicates that membrane transport proteins at the sites of xylem loading contribute to plant salinity tolerance via selective chloride exclusion. However, the molecular mechanism of xylem loading that lies behind the balance between NO3(-) and Cl(-) loading remains largely unknown. Here we identify two root anion channels in Arabidopsis, SLAH1 and SLAH3, that control the shoot NO3(-)/Cl(-) ratio. The AtSLAH1 gene is expressed in the root xylem-pole pericycle, where it co-localizes with AtSLAH3. Under high soil salinity, AtSLAH1 expression markedly declined and the chloride content of the xylem sap in AtSLAH1 loss-of-function mutants was half of the wild-type level only. SLAH3 anion channels are not active per se but require extracellular nitrate and phosphorylation by calcium-dependent kinases (CPKs) [11-13]. When co-expressed in Xenopus oocytes, however, the electrically silent SLAH1 subunit gates SLAH3 open even in the absence of nitrate- and calcium-dependent kinases. Apparently, SLAH1/SLAH3 heteromerization facilitates SLAH3-mediated chloride efflux from pericycle cells into the root xylem vessels. Our results indicate that under salt stress, plants adjust the distribution of NO3(-) and Cl(-) between root and shoot via differential expression and assembly of SLAH1/SLAH3 anion channel subunits.

Differential growth and yield responses of salt-tolerant and susceptible rice cultivars to individual (Na+ and Cl−) and additive stress effects of NaCl

Negative impacts exerted by sodium (Na+) and chloride (Cl−) ions individually as well their possible additive effects (under NaCl) were evaluated on growth and yield reductions in rice, besides investigating whether salt-tolerant genotypes respond differentially than their sensitive counterparts. Though both Na+ and Cl− ions get accumulated in plant tissues under NaCl stress, most research has historically been aimed to decipher harmful effects induced by Na+ ions. Accordingly, physiological and molecular mechanisms involved in Cl− toxicity are not clearly understood in crop plants. To address these issues, 65-day-old plants of two rice cultivars, Panvel-3 (tolerant) and Sahyadri-3 (sensitive) were subjected to Cl−, Na+ and NaCl (each with 100 mM concentration and electrical conductivity of ≈10 dS m−1) stress using soil-based systems. Stress conditions were maintained till harvesting of mature (128-day-old) plants. All three treatments induced substantial antagonistic effects on growth, dry mass, yield components (number of grains per panicle, length, width, thickness and weight of grain, along with the percentage of grains filled) and overall crop yield, with greater impacts under NaCl than its constituent ions. Salinity treatments caused an imbalance in reducing sugars, protein, starch and proline contents, with the greatest magnitude under NaCl. A negative correlation between Cl−/Na+ accumulation and crop yield was witnessed, with higher severity on the sensitive cultivar. The overall magnitude of toxicity was observed highest in NaCl followed by Na+ and Cl−, respectively, suggesting additive effects of constituent ions under NaCl. Both cultivars responded similarly; however, the tolerant cultivar, unlike the sensitive one, kept Na+:K+ ratio <1.0 and accumulated proline in response to salinity treatments used in this study.

Antioxidant response and proteomic modulations in Indian mustard grown under salt stress

Productivity of Indian mustard (Brassica juncea L. Czern. and Coss.) is markedly reduced by salt stress. To develop salt tolerance in this important oilseed crop is a need of the hour. This study, based on analysis of growth parameters and antioxidant profile of fourteen Indian mustard genotypes treated with 50, 100, 150 and 200 mM of sodium chloride, was performed to identify the salt-sensitive and salt-tolerant genotypes. Salinity stress inhibited biomass accumulation and reduced the protein and chlorophyll contents in a dose-dependent manner. The reduction was the highest in genotype Pusa Agrani and lowest in CS-54, depicting their contrasting sensitivity to salt stress. Salt treatments triggered a concentration-dependent overproduction of reactive-oxygen species and a concurrent upregulation of the expression of different antioxidants. Genotype CS-54 showed the least damage and maintained a high antioxidant level with almost each salt treatment, exhibiting its competence to withstand the damage provoked by salinity stress. Genotype Pusa Agrani, on the contrary, depicted a salt-sensitive nature by way of its very high lipid peroxidation and low intensity of antioxidants. These two genotypes were further investigated through gel-based proteomic approach, which resulted in the identification and quantification of 42 salinity-responsive proteins related to different metabolic modifications. Molecular processes, including photosynthesis, redox homeostasis, nitrogen metabolism, ATP synthesis, protein synthesis and degradation, signal transduction and respiratory pathways, have exhibited significant changes. The identified stress-responsive proteins could pave the way to develop salt tolerance in Indian mustard plant, thus sustaining its productivity under salinity.

Salt tolerance in barley originating from harsh environment of North Africa

Soil salinity is a major abiotic stress in worldwide agriculture. This has incited a quest towards with an aim of improving the crop plants. An insight into the diversity of barley landraces for salinity tolerance will facilitate their use in genetic improvement and breeding programs. Three gene pools representative of Hordeum vulgare L. grown in the North African region and collected from Tunisia, Algeria and Egypt were evaluated at the reproductive stage under non saline and two saline conditions (0, 100 and 200 mM NaCl). A total of 26 agronomic, morphological and yield-related traits were examined by analysis of variance. A significant genetic variation was observed. We successfully identified a set of accessions originating from severe agroclimatic conditions including Tozeur2, Tichedrett, Kerkena and Kebelli2 which remaining the most productive at high salinity having around 4 g grain yield production per plant and about 11 g whole plant dry weight per plant. Cluster analysis and principal component analysis were performed using salt tolerance index (STI), which provided a clear separation of barley landraces. The first three principal components (PC) contributed 64.05% and 66.01% of the variability amongst genotypes at moderate and high salinity level, respectively, with PC1 comprising yield-related traits. Significant number of highly salt tolerant genotypes grouping Early1, Tichedrett, Azrir and Giza125 from North African harsh environment was identified. Data indicate that specific barley genotypes showing differential responses against salinity could be useful as potential germplasm sources for comparative genomic studies and future breeding programs.

Analysis of Antioxidant Enzyme Activity and Antioxidant Genes Expression During Germination of Two Different Genotypes of Lolium multiflorum Under Salt Tolerance.

Annual ryegrass (Lolium multiflorum) is widely used as a cool-season forage grass for its luxuriant growth, palatable and high digestible. To investigate the salt tolerance mechanism in annual ryegrass under salt stress, salt-tolerant genotype 'R102-3' and salt-sensitive genotype 'Tetragold' were subject to 300mmol/L NaCl in a controlled growth chamber for 12 days. The results showed high concentrations of NaCl decreased relative water content (RWC), and increased the electrolyte leakage (EL) in both genotypes. However the 'Tetragold' had a greater increased extent of malondialdehyde (MDA) and EL than in 'R102-3', in contrast, the activities of Superoxide (SOD), Peroxidase (POD), Catalase (CAT) and Ascorbate peroxidase (APX) were higher in salt resistant compared to sensitive ones. For ensure the accurate of qRT-PCR, we used RefFinder to choose the most stably reference genes eEF1A(s) and GAPDH to normalize the antioxidant genes expression data. The results indicated that higher expression of Fe-SOD, Mn-SOD, Chl-Cu/Zn SOD, Cyt-Cu/Zn SOD, POD and CAT in 'R102-3' when compared with 'Tetragold', which may play an important role in defensed damage of Reactive oxygen species (ROS) under salt stress. Thus, the salt-tolerant genotype could effectively resist oxidative damage induced by salt tress relative to salt-sensitive genotype.

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.

Effect of different salt stresses on agro-morphological traits and utilisation of salt stress indices for reproductive stage salt tolerance in rice

Salinity is known to reduce rice yield in ecosystems prone to salt stress. Seasonal variations in rainfall and temperature require development of rice varieties with differential salinity tolerance. Evaluation of breeding lines under varying salinity levels will help to identify appropriate genotypes for similar salt affected areas. A set of 34 genetically and geographically diverse, representative rice genotypes was evaluated in non-stress moderate sodic (pH∼9.5), high sodic (pH∼9.9) and high saline (EC∼10dS/m) stress environments with three replications in controlled micro-plots/lysimeters for two wet seasons of 2011 and 2012. The stress intensity (SI) for grain yield under moderate sodic, high sodic and high saline environments as compared to non-stress was 0.28, 0.77 and 0.56, respectively. Compared to the non-stress, the per cent grain yield reduction under moderate sodicity ranged from 7 (IR78806-B-B-16-1-2-2-AJY1) to 76% (Pusa 44), while under high sodicity and high salinity, it ranged from 44 (CSR 27) to 97% (PR 120) and 28 (CSR-RIL-50) to 91% (Pusa 44) respectively. Amongst the genotypes evaluated, highest stress tolerance indices (STI) were noticed in genotype CSR 36 (2.17, 1.27 and 1.15 in moderate sodicity, high sodicity and high salinity, respectively), whereas the lowest STI was recorded in genotype NDR 359 (0.27 and 0.05 in moderate sodicity, high sodicity) and TR-2000-008 (0.18 in high salinity). Similarly, genotype CSR 36 registered the highest geometric mean productivity (GMP) and mean productivity (MP) in all stress conditions. The biplot analysis of grain yield showed that the stress tolerance attributes MP, GMP, STI and grain yield favored salt tolerant genotypes CSR 23, CSR 27, CSR 36, CSR-RIL-197, HKR 127 and IR60997-16-2-3-2-2R. The sensitive genotypes PR 113, PR 114, PR 118, PR 120, Pusa 44, TR-2000-008 and VSR 156 were favored by other indices TOL and SSI. Thus, a combination of salt stress indices helps in selection of stable rice genotypes for reproductive stage salt tolerance. Selection based on salt stress indices coupled with trait correlation resulted in the identification of high yielding reproductive stage salt tolerant genotypes viz. CSR 36, CSR 23, CSR 27 and CSR-RIL-197.

Screening Oryza glaberrima Genotypes for Salt Tolerance at Seedling Stage

Screening Oryza glaberrima Genotypes for Salt Tolerance at Seedling Stage

The nuclear protein GmbZIP110 has transcription activation activity and plays important roles in the response to salinity stress in soybean.

Plant basic-leucine zipper (bZIP) transcription factors play important roles in many biological processes and are involved in the regulation of salt stress tolerance. Previously, our lab generated digital gene expression profiling (DGEP) data to identify differentially expressed genes in a salt-tolerant genotype of Glycine soja (STGoGS) and a salt-sensitive genotype of Glycine max (SSGoGM). This DGEP data revealed that the expression (log2 ratio) of GmbZIP110 was up-regulated 2.76-fold and 3.38-fold in SSGoGM and STGoGS, respectively. In the present study, the salt inducible gene GmbZIP110 was cloned and characterized through phylogenetic analysis, subcellular localization and in silico transcript abundance analysis in different tissues. The functional role of this gene in salt tolerance was studied through transactivation analysis, DNA binding ability, expression in soybean composite seedlings and transgenic Arabidopsis, and the effect of GmbZIP110 on the expression of stress-related genes in transgenic Arabidopsis was investigated. We found that GmbZIP110 could bind to the ACGT motif, impact the expression of many stress-related genes and the accumulation of proline, Na+ and K+, and enhanced the salt tolerance of composite seedlings and transgenic Arabidopsis. Integrating all these results, we propose that GmbZIP110 plays a critical role in the response to salinity stress in soybean and has high potential usefulness in crop improvement.

Evaluation of Different Radish (&amp;lt;i&amp;gt;Raphanus sativus&amp;lt;/i&amp;gt;) Genotypes under Different Saline Regimes

An effective and simple screening technique for identification of salt tolerant and salt sensitive radish genotypes was observed. Sand is used as potting media. Six genotypes of radish were used for screening against four salinity levels (0, 1, 3, 5 and 7 dS/m-1). Twenty days old seedlings of radish were salinized with salt solution (NaCl). Morphological, physiological and ionic parameters were studied. Radish genotypes Laal-Pari and 40 Days executed the best performance in all the measured attributes and categorized as salt tolerant genotype while Green Neck was the poorest in retaining normal functioning at higher salinity levels thus grouped under salt sensitive cultivar.

Detection of Salt Tolerant Gene (&amp;lt;i&amp;gt;TaNIP&amp;lt;/i&amp;gt;) and Its Expression in Three Selected Wheat Genotypes Through Plant Breeding Programs Under Salinity Conditions

High soil salinity is a major abiotic stress in plant production worldwide. <i>TaNIP</i> gene was identified and cloned through the gene chip expression analysis of a salt- tolerant wheat mutant RH8706-49 under salt stress. Quantitative reverse transcription – PCR (Q-RT-PCR) was used to detect <i>TaNIP</i> salt tolerant gene and its expression in some selected wheat genotype for salt tolerance through plant breeding programs. The results of qualitative PCR Reaction- cDNA and Quantitative Real-Time PCR showed that the gene band appeared only in the selected genotypes with length 189bp, while this band absent in salt sensitive cultivar (Iraq) under salinity and non-salinity condition. Amount and expression of <i>TaNIP</i> gene to be enhanced under salinity condition only in the selected salt tolerant genotype, and they increased with increasing salt level. Great expression and amount of <i>TaNIP</i> gene was at high salinity level (20 ds/m). The selected salt tolerant genotype had proximately similar amount and expression of <i>TaNIP</i> gene under all salinity condition, while there had no amounts and expression of this gene in sensitive cultivar (Iraq) therefore according to this gene (<i>TaNIP</i>) there is improvement realized in these selected genotypes for salt tolerance through plant breeding programs.

Salinity tolerance of chickpea genotypes (&lt;i&gt;Cicer Arietinum&lt;/i&gt; L.) and symbiotic performance in arid saline environment

The present study was conducted to screen of chickpea genotypes for salt tolerance and to determine the response of salt tolerant chickpea genotypes to inoculation with Mezorhizobium ciceri in search for the best Rhizobium /chickpea combinations. Results of analysis of variance showed that there were significant differences among evaluated genotypes which showed high genetic diversity for salt tolerance. Germination percentage and seedling growth characters of all chickpea genotypes were decreased by salinity increasing from 0.5 ds•m −1 to 10.0 ds•m −1 . The results showed that the growth and nodulation of varieties Uzbekiston-32, Xalima, Miroz, Flip 1-33 and CIEW-45 were much better in salinated soil compared other chickpea genotypes. Inoculation of salt tolerant chickpea varieties with M.ciceri IC53 significantly increased numbers of nodules on the roots (30%), shoot and root dry weight (27%), pod numbers (28%) and yield (23%). From the above results, it has been revealed that for achieving the highest symbiotic effectiveness under salinity conditions plant varieties have to be taken into account. It could be suggested that cultivation of salt tolerant genotypes with its symbiotic partners could be an effective selection technology to overcome on salinity problems of saline soils of Uzbekistan.

Assessment of genetic diversity of Saltol QTL among the rice (Oryza sativa L.) genotypes.

Eight Saltol quantitative trait locus (QTL) linked simple sequence repeat (SSR) markers of rice (Oryza sativa L.) were used to study the polymorphism of this QTL in 142 diverse rice genotypes that comprised salt tolerant as well as sensitive genotypes. The SSR profiles of the eight markers generated 99 alleles including 20rare alleles and 16 null alleles. RM8094 showed the highest number (13) of alleles followed by RM3412 (12), RM562 (11), RM493 (9) and RM1287 (8) while as, RM10764 and RM10745 showed the lowest number (6) of alleles. Based on the highest number of alleles and PIC value (0.991), we identified RM8094 as suitable marker for discerning salt tolerant genotypes from the sensitive ones. Based upon the haplotype analysis using FL478 as a reference (salt tolerant genotypes containing Saltol QTL), we short listed 68 rice genotypes that may have at least one allele of FL478 haplotype. Further study may confirm that some of these genotypes might have Saltol QTL and can be used as alternative donors in salt tolerant rice breeding programmes.

In vitro Screening of Salt Tolerent Genotypes in Tomato (Solanum lycopersicum L.)

Soil salinity is one of the most important abiotic stress that limit crop production. Tomato (Solanum lycopersicum L.) is moderately tolerant to salinity and is typically cultivated in regions that are exposed to soil salinization. The aim of the study was to characterize phenotype response to salt stress under in vitro conditions of fourteen tomato genotypes. The shortest root length was observed entries BD-7260 at 250 mM. Longer roots (11.6 cm) were developed by the plants from the solutions containing 50 mM NaCl in entries BD-7302. NaCl concentration in the medium significantly affected the root length and plant weight of tomato. Genotypic distribution of weight LS means revealed that genotypes BARI-2 and the Line BD-7292 is the highest performed and the Line BD-7762 is the lowest performed. These findings indicated some salt tolerant tomato genotypes which will be promising for future hybridization program. Analysis of novel genes as well as some previously identified genes such as PIPs, LTPs, AGPs, PRPs, GRPs etc. which showed protective roles in different abiotic stresses to other crops is quiet necessary and the presence and expression pattern of those genes in these screened genotypes of tomato will provide powerful information for over-expression of those genes in transgenic plants those will confer salt tolerances to the cultivated tomato varieties.

Identification of barley landrace genotypes with contrasting salinity tolerance at vegetative growth stage.

In the present study, we evaluated the behavior of 21 Tunisian barley landraces under salt stress. The evaluation was performed using 14 morphological and physiological traits at vegetative growth stage under severe salt stress (200 and 250 mM). A multivariate analysis was used in order to select the genotypes with contrasting behavior towards salinity and to identify the major traits conferring salinity tolerance. According to the PCA analyses the genotypes exhibited diverse behavior with the salt stress concentration, indeed 3 different clustering profiles were obtained. Eleven quantitative characters were considered the most pertinent for the ranking of genotypes for salt tolerance. Among them the total fresh weight and the net CO2 assimilation rate were the most discriminating descriptors at 250 mM NaCl. These parameters allowed as the identification of the contrasting pair genotypes toward salinity. "Testour" was classified as the most sensitive and "Enfidha" the most tolerant toward salinity stress. These findings would be of great relevance in breeding programs.

Morpho- biochemical evaluation of Brassica rapa sub-species for salt tolerance

Salt stress is one of the key abiotic stresses that affect both the qualitative and quantitative characters of many Brassica rapa sub-species by disturbing its normal morphobiochemical processes. Therefore, the present research work was designed to study the effect of different NaCl events (0, 50,100 and 150 mmol) on morphological and biochemical characters and to screen salt tolerant genotypes among brown, yellow and toria types of B. rapa sub-species. The plants were grown in test tubes with addition of four level of NaCl (0, 50,100 and 150 mmol). The effect of salinity on shoot and root length, shoot/ root fresh and dry weight, relative water content (RWC), proline and chlorophyll a, b, a+b contents was recorded after 4 weeks of sowing. The genotype 22861 (brown type) showed excellent morphological and biochemical performance at all stress levels followed by Toria-Sathi and Toria-A respectively as compared to Check variety TS-1. The genotype 26158 (yellow type) gave very poor performance and retard growth. The %RWC values and chlorophyll a, b and a+b contents were decreased several folds with the increase of salt concentration. While, the proline contents was increased with raising of salt stress. The brown and toria types showed maximum tolerance to salt stress at early germination stages as compare to yellows one. The present study will serve as model to develop quick salt tolerant genotypes among different plant sub-species against salt stress.

Changes in gene expression and catalase activity in Oryza sativa L. under abiotic stress.

Different rice (Oryza sativa L.) genotypes were subjected to high salinity and low temperature (150 mM NaCl and 13°C, respectively) for 0, 6, 24, 48, or 72 h. We evaluated the simultaneous expression of the genes OsCATA, OsCATB, and OsCATC, correlated gene expression with enzyme activity, and verified the regulation of these genes through identification of cis-elements in the promoter region. The hydrogen peroxide content increased in a tolerant genotype and decreased in a sensitive genotype under both stress conditions. Lipid peroxidation increased in the tolerant genotype when exposed to cold, and in the sensitive genotype when exposed to high salinity. Catalase activity significantly increased in both genotypes when subjected to 13°C. In the tolerant genotype, OsCATA and OsCATB were the most responsive to high salinity and cold, while in the sensitive genotype, OsCATA and OsCATC responded positively to saline stress, as did OsCATA and OsCATB to low temperature. Cis-element analysis identified different regulatory sequences in the catalase promoter region of each genotype. The sensitive genotype maintained a better balance between hydrogen oxyacid levels, catalase activity, and lipid peroxidation under low temperature than the resistant genotype. OsCATA and OsCATB were the most responsive in the salt-tolerant genotype to cold, OsCATA and OsCATC were the most responsive to saline stress, and OsCATA and OsCATB were the most responsive to chilling stress in the sensitive genotype. There were positive correlations between catalase activity and OsCATB expression in the tolerant genotype under saline stress and in the sensitive genotype under cold stress.

Evaluation of wheat genotypes for salt tolerance based on some physiological traits

Identification of physiological markers related with salt tolerance during various vegetative and reproductive stages is crucial for evaluating wheat genotypes and improving their salt tolerance. Two salt-tolerant (Shatabdi and BAW 1135) and two salt-sensitive (BARI Gom 26 and BAW 1122) wheat genotypes of Bangladesh were grown in three salinity levels (control, 6 dS m-1, and 12 dS m-1) to observe the sensitivity of some physiological traits.. Salt-tolerant wheat genotypes maintained lower levels of leaf Na, higher levels of leaf K, and greater K/Na ratios in saline conditions than the sensitive one. Due to salt stress, flag leaf proline content was increased in salt-tolerant wheat genotypes whereas the proline level was decreased in the sensitive one compared to the control. Salt-sensitive genotypes showed a greater increment in SPAD (relative chlorophyll content) value at moderate salt stress but a greater reduction in SPAD values at high salt stress than tolerant ones. Salt-sensitive genotypes were affected more in their straw yield and finally grain yield plants-1 under saline conditions than salt-tolerant genotypes. There was a highly significant negative correlation between grain yield and Na content and also a highly significant negative correlation between grain yield and K: Na content of the wheat genotypes under saline environments. We also observed stress susceptibility index (SSI) based on grain yield plant-1 the order of tolerance was BAW 1135 > Shatabdi > BARI Gom 26 > BAW 1122 at moderate salinity level and BAW 1135 > Shatabdi > BAW 1122 > BARI Gom 26 at high salinity.