Evaluation Of Salt Tolerance Research Articles

Marker-Assisted Introgression of the Salinity Tolerance Locus Saltol in Temperate Japonica Rice

BackgroundRice is one of the most salt sensitive crops at seedling, early vegetative and reproductive stages. Varieties with salinity tolerance at seedling stage promote an efficient growth at early stages in salt affected soils, leading to healthy vegetative growth that protects crop yield. Saltol major QTL confers capacity to young rice plants growing under salt condition by maintaining a low Na+/K+ molar ratio in the shoots.ResultsMarker-assisted backcross (MABC) procedure was adopted to transfer Saltol locus conferring salt tolerance at seedling stage from donor indica IR64-Saltol to two temperate japonica varieties, Vialone Nano and Onice. Forward and background selections were accomplished using polymorphic KASP markers and a final evaluation of genetic background recovery of the selected lines was conducted using 15,580 SNP markers obtained from Genotyping by Sequencing. Three MABC generations followed by two selfing, allowed the identification of introgression lines achieving a recovery of the recurrent parent (RP) genome up to 100% (based on KASP markers) or 98.97% (based on GBS). Lines with highest RP genome recovery (RPGR) were evaluated for agronomical-phenological traits in field under non-salinized conditions. VN1, VN4, O1 lines were selected considering the agronomic evaluations and the RPGR% results as the most interesting for commercial exploitation. A physiological characterization was conducted by evaluating salt tolerance under hydroponic conditions. The selected lines showed lower standard evaluation system (SES) scores: 62% of VN4, and 57% of O1 plants reaching SES 3 or SES 5 respectively, while only 40% of Vialone Nano and 25% of Onice plants recorded scores from 3 to 5, respectively. VN1, VN4 and O1 showed a reduced electrolyte leakage values, and limited negative effects on relative water content and shoot/root fresh weight ratio.ConclusionThe Saltol locus was successfully transferred to two elite varieties by MABC in a time frame of three years. The application of background selection until BC3F3 allowed the selection of lines with a RPGR up to 98.97%. Physiological evaluations for the selected lines indicate an improved salinity tolerance at seedling stage. The results supported the effectiveness of the Saltol locus in temperate japonica and of the MABC procedure for recovering of the RP favorable traits.

Analysis of Effect of Compound Salt Stress on Seed Germination and Salt Tolerance Analysis of Pepper (Capsicum annuum L.).

To determine the salt tolerance and physiological mechanism of pepper (Capsicum annuum L.) at the germination stage, the Hongtianhu 101 and Xinxiang 8 varieties, which have large differences in salt tolerance, are employed as the study materials. Six mixed salt concentrations of 0, 3, 5, 10, 15, and 20 g/L derived using equal molar ratios of Na2CO3, NaHCO3, NaCl, CaCl2, MgCl2, MgSO4, and Na2SO4 are used. To determine their effects, the related indexes of seed germination, seedling growth, and physiology are measured, and salt tolerance is comprehensively evaluated using membership function analysis. The results show that as the mixed salt concentration increases, the germination potential, germination index, germination rate, seed germination vigor index, root length, and root fresh weight of the two cultivars significantly decrease, whereas the relative salt rate gradually increases. The hypocotyl length and fresh weight aboveground increase first and then decrease, while the malondialdehyde (MDA), proline (Pro) content, catalase (CAT), peroxidase (POD), and superoxide dismutase (SOD) activity decrease and then increase. The germination potential, germination index, germination rate, seed germination vigor index, root length, root fresh weight, MDA and Pro content, and CAT activity of the Hongtianhu 101 seeds are higher than those of Xinxiang 8 for all salt concentrations employed here. However, hypocotyl length, fresh weight aboveground, and relative salt rate are lower in Hongtianhu 101 than in Xinxiang 8. The comprehensive evaluation of salt tolerance reveals that the total weighted values of the two membership function indexes increase first and then decrease as the mixed salt concentration increases. Compared with 5 g/L, which has the highest membership function value, the index under salt concentrations of 3 g/L, 10 g/L, and 15 g/L decreases by 4.7%-11.1%, 25.3%-28.3%, and 41.4%-45.1%, respectively. This study provides theoretical guidance for the breeding of salt-tolerant varieties of pepper and an analysis of the physiological mechanisms involved in salt tolerance and salt-tolerant cultivation.

Evaluation of salt tolerance in common vetch (Vicia sativa L.) germplasms and the physiological responses to salt stress

Common vetch (Vicia sativa L.) is an important leguminous crop, providing humans with starch from seeds, feeding livestock with vegetative organs, or fertilizing soils by returning to field. It is aimed to evaluate salt tolerance in common vetch collections for breeding programs and to investigate the underlined physiological mechanisms. Relative germination rate and relative seedling growth showed great difference among common vetch collections in response to salt. A lower level of Na+ and higher levels of K+ and K+/Na+ ratio were maintained in both shoots and roots in salt-tolerant collections than in salt-sensitive ones under salt stress. Expression of the genes involved in transportation and redistribution of Na+ and K+ were cooperatively responsible for salt stress. Transcript levels of NHX7, HKT1, AKT2, and HAK17 in leaves and roots were induced after salt stress, with higher transcript levels in salt-tolerant collections compared with the sensitive ones. Proline and P5CS1 transcript levels were increased after salt stress, with higher levels in salt-tolerant collection compared with salt-sensitive ones. Both O2− and H2O2 were accumulated after salt stress, and lower levels were accumulated in salt-tolerant collection compared with salt-sensitive ones. Superoxide dismutase, catalase and ascorbate peroxidase activities were altered in response to salt and higher levels were maintained in salt-tolerant collections compared with salt-sensitive ones. It is suggested that salt tolerance in common vetch is associated with maintenance of K+ and Na+ homeostasis and the associated gene expression and promoted proline accumulation and antioxidant defense system.

Screening of salt tolerance traits and the salt tolerance evaluation method in <em>Brassica napus</em> at the seed germination stage

Soil salinity is one of the major abiotic stresses that negatively affect plant growth and agricultural productivity. For many crop species, the germination stage is one of the most sensitive stages to salinity stress. This study evaluated salt tolerance in 200 Brassica napus L. germplasms using hierarchical cluster analysis based on multiple morphological parameters, including germination rate, root length, fresh weight of root, shoot length, fresh weight of shoot, and total fresh weight. Membership function was used as a comprehensive index to select and evaluate salt tolerance of these germplasms, identifying 8 highly salt-tolerant germplasms, 40 salt-tolerant germplasms, 65 moderate salt-tolerant germplasms, 52 salt-sensitive germplasms, and 35 highly saltsensitive germplasms lines. The responses of rapeseed germplasm to salt stress indicate differences in morphological parameters. Furthermore, NaCl showed a positive effect on total fresh weight and biomass production of some germplasms at a concentration of 100 mmol L–1. Since the correlation value of salt tolerance with total fresh weight was highest under 200 mmol L–1 NaCl, it can be considered the most reliable parameter to evaluate salt tolerance. Therefore, the findings of this study can be applied as an effective and reliable method for mass screening and evaluation of Brassica napus germplasm at the germination stage for breeding salt-tolerant rapeseed genotypes. Highlights - The salinity tolerance of 200 varieties of B. napus germplasms was investigated. - B. napus is more vulnerable to saline conditions during the germination and early reproductive stages than the vegetative and flowering periods. - Based on hierarchical cluster analysis, there was a wide variability of salinity tolerance among rapeseed germplasm. - Low concentration of sodium chloride had a positive effect on shoot and root growth, germination and total weight in some B. napus seedlings. - Total fresh weight can be utilized as the most efficient index for mass screening of salt tolerance in B. napus germplasms at the germination stage.

Phenotypic Differences and Physiological Responses of Salt Resistance of Walnut with Four Rootstock Types.

Walnut is one of the world’s four largest nuts. Currently, the bottleneck in walnut breeding is the production of resistant variants. Soil salinization is a global problem, and the use of salt-tolerant rootstocks is a basic strategy to overcome the challenge of sustained walnut production. Providing a scientific basis for the selection of walnut salt-tolerant rootstocks is possible by studying the physiological and biochemical response characteristics and salt tolerance variations of different walnut genotypes under salt stress. In the present study, seedlings of four genotypes of walnut rootstocks, including J1 (Juglans hindsii), J2 (J. mandshurica), J3 (J. regia × J. mandshurica), and J4 (J. regia × J. hindsii), were employed as test materials to conduct a 28-day pot experiment under NaCl stress with five NaCl concentrations (0, 50, 100, 200, and 300 mmol/L). Under different NaCl treatment concentrations, seedling morphology, growth indices, chlorophyll content, photosynthetic parameters, relative electrical conductivity (REC), malondialdehyde (MDA), proline (Pro), soluble sugar (SS), and the activity of superoxide dismutase (SOD) and peroxidase (POD) in the leaves were examined. Salt stress altered the morphological characteristics and growth indices of seedlings from four genotypes to varying degrees. In addition, according to the analysis of physiological and biochemical data, salt stress had a considerable impact on both the physiological and biochemical processes of seedlings. Salt stress decreased the chlorophyll content and photosynthetic parameters of four genotypes, the REC, MDA content, Pro content, and SS content of each genotype increased by different degrees, and the enzymatic activities showed different trends. The salt tolerance of rootstocks was evaluated thoroughly using principal component analysis and membership function analysis based on the 16 parameters. The results of a comprehensive evaluation of salt tolerance showed that the order of salt tolerance of the four genotypes was J4 > J1 > J3 > J2, which corresponded to the order of the morphological symptoms of salt injury. In conclusion, J4 has strong salt tolerance and is an important germplasm resource for walnut salt-tolerant rootstock breeding.

Study on the Relationship of Ions (Na, K, Ca) Absorption and Distribution to Photosynthetic Response of Salix matsudana Koidz Under Salt Stress.

To identify the key indicators for salt tolerance evaluation of Salix matsudana Koidz, we explored the relationship of ion absorption and distribution with chlorophyll, fluorescence parameters (leaf performance index, maximum photochemical efficiency), and photosynthetic gas parameters (net photosynthetic rate, transpiration, stomatal conductance, intercellular carbon dioxide concentration) under salt stress. We established 4 treatment groups and one control group based on salinity levels of NaCl hydroponic solutions (171, 342, 513, and 684 mm). The Na+/K+, Na+/Ca2+, chlorophyll fluorescence, and photosynthetic parameters of leaves were measured on the 1st, 3rd, 5th, 8th, 11th, and 15th days to analyze the correlations of chlorophyll, chlorophyll fluorescence and photosynthetic parameters to the ion distribution ratio. The results showed that (1) The ratio of the dry weight of roots to leaves gradually increased with increasing salt concentration, whereas the water content of leaves and roots first increased and then decreased with increasing time. (2) The content of Na+, Na+/K+, and Na+/Ca2+ in roots and leaves increased with increasing salt stress concentration and treatment time, and the difference gradually narrowed. (3) Ca2+ was lost more than K+ under salt stress, and Na+/Ca2+ was more sensitive to the salt stress environment than Na+/K+. (4) Because the root system had a retention effect, both Na+/K+ and Na+/Ca2+ in roots under different NaCl concentrations and different treatment times were higher than those in leaves, and Na+/Ca2+ was much higher than Na+/K+ in roots. (5) Na+/K+ had a higher correlation with fluorescence parameters than Na+/Ca2+. Among them, Na+/K+ had a significantly negative correlation with the maximum photochemical efficiency, and the correlation coefficient R2 was 0.8576. (6) Photosynthetic gas parameters had a higher correlation with Na+/Ca2+ than with Na+/K+. Among them, significantly negative correlations were noted between Na+/Ca2+ and Gs as well as between Na+/Ca2+ and E under salt stress. The correlation between Na+/Ca2+ and Gs was the highest with a correlation coefficient of 0.9368. (7) Na+/K+ and Na+/Ca2+ had no significant correlation with chlorophylls. Na+/Ca2+ was selected as a key index to evaluate the salt tolerance of S. matsudana Koidz, and the results provided a reference for analyzing the relationship between ion transport and distribution for photosynthesis.

Evaluation of salt tolerance of oat cultivars and the mechanism of adaptation to salinity

Soil salinity is a threat to agricultural production worldwide. Oat (Avena sativa L.) is an irreplaceable crop in areas with fragile ecological conditions. However, there is a lack of research on salt tolerance evaluation of oat germplasm resources. Therefore, the purpose of this work was to evaluate the salt tolerance of oat cultivars and investigate the mechanism of salt-tolerant oat cultivars’ adaptation to salinity. Salt tolerance of 100 oat cultivars was evaluated, and then two salt-tolerant cultivars and two salt-sensitive cultivars were used to compare their physiological responses and expression patterns of Na+- and K+-transport-related genes under salinity. Principal component analysis and membership function analysis had good predictability for salt tolerance evaluation of oat and other crops. The 100 oat cultivars were clustered into three categories, with three salt tolerance levels. Under saline condition, salt-tolerant cultivars maintained higher growth rate, leaf cell membrane integrity, and osmotic adjustment capability via enhancing the activities of antioxidant enzymes and accumulating more osmotic regulators. Furthermore, salt-tolerant cultivars had stronger capability to restrict root Na + uptake through reducing AsAKT1 and AsHKT2;1 expression, exclude more Na+ from root through increasing AsSOS1 expression, compartmentalize more Na + into root vacuoles through increasing AsNHX1 and AsVATP-P1 expression, and absorb more K+ through increasing AsKUP1 expression, compared with salt-sensitive cultivars. The evaluation procedure developed in this work can be applied for screening cereal crop cultivars with higher salt tolerance, and the elucidated mechanism of oat adaptation to salinity lays a foundation for identifying more functional genes related to salt tolerance.

Silicon improves ion homeostasis and growth of liquorice under salt stress by reducing plant Na+ uptake

Silicon (Si) effectively alleviates the effects of salt stress in plants and can enhance salt tolerance in liquorice. However, the mechanisms by which Si improved salt tolerance in liquorice and the effects of foliar application of Si on different liquorice species under salt stress are not fully understood. We investigated the effects of foliar application of Si on the growth, physiological and biochemical characteristics, and ion balance of two liquorice species, Glycyrrhiza uralensis and G. inflata. High salt stress resulted in the accumulation of a large amount of Na+, decreased photosynthetic pigment concentrations, perturbed ion homeostasis, and eventually inhibited both liquorice species growth. These effects were more pronounced in G. uralensis, as G. inflata is more salt tolerant than G. uralensis. Foliar application of Si effectively reduced the decomposition of photosynthetic pigments and improved gas exchange parameters, thereby promoting photosynthesis. It also effectively inhibited lipid peroxidation and leaf electrolyte leakage and enhanced osmotic adjustment of the plants. Furthermore, Si application increased the K+ concentration and reduced Na+ absorption, transport, and accumulation in the plants. The protective effects of Si were more pronounced in G. uralensis than in G. inflata. In conclusion, Si reduces Na+ absorption, improves ion balance, and alleviates the negative effects of salt stress in the two liquorice species studied, but the effect is species dependent. These findings may help to develop novel strategies for protecting liquorice plants against salt stress and provide a theoretical basis for the evaluation of salt tolerance and the scientific cultivation of liquorice.

Effect of salt stress on the photosynthetic characteristics and endogenous hormones, and: A comprehensive evaluation of salt tolerance in Reaumuria soongorica seedlings

ABSTRACT Salinity is a major limiting factor in desert ecosystems, where Reaumuria soongarica is a dominant species. It is crucial to study the growth and physiological response mechanisms of R. soongorica under salt stress for the protection and restoration of the desert ecosystems. However, the effects of salt concentration and stress duration on endogenous hormonal content and photosynthetic efficiency and salt injury index of R. soongorica leaves have not been reported. Currently, there is no systematic evaluation system to determine physiological adaptation strategies of R. soongorica seedlings in response to salt stress. In this study, simulation experiments were performed with NaCl solution mixed with soil. Enzyme-linked immunosorbent assay and LI-6800 portable photosynthesis analyzer were used to measure indole acetic acid (IAA), corn nucleoside hormone (ZR), abscisic acid (ABA), and photosynthesis-related parameters in leaves of R. soongorica seedlings at 0 (24–48 h after salt treatment), 3, 6, and 9 days. At the same time, growth indicators (salt injury index, root-to-shoot ratio), reactive oxygen species content, superoxide dismutase enzyme (SOD) activity, osmolyte content, membrane peroxidation, and leaf pigment content were measured at different salt concentrations and treatment times. Finally, principal component analysis and membership function method were used to comprehensively evaluate the salt tolerance of seedlings. The results showed that treatment with 200 mM NaCl for 3 days significantly increased SOD activity, the content of osmotic adjustment substances (proline, soluble protein), endogenous hormone content (ABA, ZR), root-to-shoot ratio, and Chla/Chlb values but decreased malondialdehyde content (MDA) in the leaves of R. soongorica seedlings. Leaf water content (LRWC), net photosynthetic rate (Pn), transpiration rate (Tr), water use efficiency (WUE), and IAA content in R. soongorica seedlings were lower than those in the control, when exposed to 400 and 500 mM NaCl solutions. Finally, the principal component analysis revealed endogenous hormone content and antioxidant enzyme activity to be useful for the comprehensive evaluation of salt tolerance in R. soongorica seedlings. The R. soongorica seedlings showed the strongest salt tolerance when exposed to 200 mM NaCl for 3 days. This study provides a theoretical foundation for gene mining and breeding of salt-tolerant species in the future.

Evaluation of Salt Tolerance during the Seed Germination Stage of Five Varieties of Vicia sativa

Background: Common vetch (Vicia sativa L.) is a legume that is widely used as pasture, silage and livestock feed. However, the area of secondary Saline-Alkali land throughout the world has been increasing, resulting to lower crop yields. Therefore, high-yielding common vetch varieties with good tolerance to salt must be identified. Methods: Salt tolerance during the seed germination stage of five common vetch varieties was assessed using gray correlation, standard deviation coefficient allocation weighted method and membership function value. Result: Seedling growth characteristics were significantly reduced by increased salt concentration. Notably, while the seed germination potential of the varieties decreased significantly at 0.9% salt concentration, excluding that of 333A, these decreased values for germination potential were still more than 50% higher than that of the control. Based on gray correlation methods and membership function values, varieties were graded according to salt tolerance, in which 22216 was the best, followed by Sujian 3, 7504 and 1586, while 333A was the worst.

Genetic architecture of salt tolerance in a Multi-Parent Advanced Generation Inter-Cross (MAGIC) cowpea population

BackgroundPrevious reports have shown that soil salinity is a growing threat to cowpea production, and thus the need for breeding salt-tolerant cowpea cultivars. A total of 234 Multi-Parent Advanced Generation Inter-Cross (MAGIC) lines along with their 8 founders were evaluated for salt tolerance under greenhouse conditions. The objectives of this study were to evaluate salt tolerance in a multi-parent advanced generation inter-cross (MAGIC) cowpea population, to identify single nucleotide polymorphism (SNP) markers associated with salt tolerance, and to assess the accuracy of genomic selection (GS) in predicting salt tolerance, and to explore possible epistatic interactions affecting salt tolerance in cowpea. Phenotyping was validated through the use of salt-tolerant and salt-susceptible controls that were previously reported. Genome-wide association study (GWAS) was conducted using a total of 32,047 filtered SNPs. The epistatic interaction analysis was conducted using the PLINK platform.ResultsResults indicated that: (1) large variation in traits evaluated for salt tolerance was identified among the MAGIC lines, (2) a total of 7, 2, 18, 18, 3, 2, 5, 1, and 23 were associated with number of dead plants, salt injury score, leaf SPAD chlorophyll under salt treatment, relative tolerance index for leaf SPAD chlorophyll, fresh leaf biomass under salt treatment, relative tolerance index for fresh leaf biomass, relative tolerance index for fresh stem biomass, relative tolerance index for the total above-ground fresh biomass, and relative tolerance index for plant height, respectively, with overlapping SNP markers between traits, (3) candidate genes encoding for proteins involved in ion transport such as Na+/Ca2+ K+ independent exchanger and H+/oligopeptide symporter were identified, and (4) epistatic interactions were identified.ConclusionsThese results will have direct applications in breeding programs aiming at improving salt tolerance in cowpea through marker-assisted selection. To the best of our knowledge, this study was one of the earliest reports using a MAGIC population to investigate the genetic architecture of salt tolerance in cowpea.

A Comprehensive Evaluation of Salt Tolerance in Tomato (Var. Ailsa Craig): Responses of Physiological and Transcriptional Changes in RBOH's and ABA Biosynthesis and Signalling Genes.

Salinity is a ubiquitous stressor, depleting osmotic potential and affecting the tomato seedlings’ development and productivity. Considering this critical concern, we explored the salinity response in tomato seedlings by evaluating them under progressive salt stress duration (0, 3, 6, and 12 days). Intriguingly, besides the adverse effect of salt stress on tomato growth the findings exhibited a significant role of tomato antioxidative system, RBOH genes, ABA biosynthesis, and signaling transcription factor for establishing tolerance to salinity stress. For instance, the activities of enzymatic and non-enzymatic antioxidants continued to incline positively with the increased levels of reactive oxygen species (O2•−, H2O2), MDA, and cellular damage, suggesting the scavenging capacity of tomato seedlings against salt stress. Notably, the RBOH transcription factors activated the hydrogen peroxide-mediated signalling pathway that induced the detoxification mechanisms in tomato seedlings. Consequently, the increased gene expression of antioxidant enzymes and the corresponding ratio of non-enzymatic antioxidants AsA-GSH suggested the modulation of antioxidants to survive the salt-induced oxidative stress. In addition, the endogenous ABA level was enhanced under salinity stress, indicating higher ABA biosynthesis and signalling gene expression. Subsequently, the upregulated transcript abundance of ABA biosynthesis and signalling-related genes suggested the ABA-mediated capacity of tomato seedlings to regulate homeostasis under salt stress. The current findings have revealed fascinating responses of the tomato to survive the salt stress periods, in order to improve the abiotic stress tolerance in tomato.

Evaluation of Thellungiella halophila ST7 for improving salt tolerance in cotton

BackgroundGossypium hirsutum (upland cotton) is one of the principal fiber crops in the world. Cotton yield is highly affected by abiotic stresses, among which salt stress is considered as a major problem around the globe. Transgenic approach is efficient to improve cotton salt tolerance but depending on the availability of salt tolerance genes.ResultsIn this study we evaluated salt tolerance candidate gene ST7 from Thellungiella halophila, encoding a homolog of Arabidopsis aluminum-induced protein, in cotton. Our results showed that ThST7 overexpression in cotton improved germination under NaCl stress as well as seedling growth. Our field trials also showed that ThST7 transgenic cotton lines produced higher yield under salt stress conditions. The improved salt tolerance of the transgenic cotton lines was partially contributed by enhanced antioxidation as shown by diaminobenzidine (DAB) and nitrotetrazolium blue chloride (NBT) staining. Moreover, transcriptomic analysis of ThST7 overexpression lines showed a significant upregulation of the genes involved in ion homeostasis and antioxidation, consistent with the salt tolerance phenotype of the transgenic cotton.ConclusionsOur results demonstrate that ThST7 has the ability to improve salt tolerance in cotton. The ThST7 transgenic cotton may be used in cotton breeding for salt tolerance cultivars.

THIẾT LẬP ĐIỀU KIỆN TẠO VÀ NUÔI CẤY CALLUS IN VITRO CHO NGHIÊN CỨU STRESS MẶN Ở GIỐNG LÚA KHANG DÂN 18

The Khang Dan 18 is one of the rice cultivars widely cultivated in Vietnam, which is threatened by saline intrusion. This study is conducted to establish an in vitro culture system for evaluate salt tolerance of the rice cultivar Khang Dan 18. First, different culture conditions, including plant growth regulator concentration, culture period, light regime, were optimized to induce and maintain callus in vitro. Culture media supplemented with 10 - 40 µM 2,4- Dichlorophenoxyacetic acid (2,4-D) are suitable for inducing callus. Different culture periods (1, 2 and 4 weeks) significantly affected the callus morphology and nature. The 10-hour light photoperiod is the most effective condition for callus induction and multiplication. Callus cultured in the medium supplemented exclusively with 2,4-D showed higher quality compared to those in media supplemented with 1-Naphthylacetic acid (NAA) and 2,4-D. Different photoperiods also affected callus differentiation in terms of root\shoot induction. The established culture system was then employed to evaluate salt tolerance of the callus. The growth of callus was significantly decreased when the concentrations of NaCl increased (3, 6 and 9‰, P = 0.05), especially at the concentration of 9‰ NaCl caused a strong decrease in callus weight and an obvious change in callus morphology. This culture system may be applied for in vitro salt stress studies on the cultivar Khang Dan 18 and similar rice cultivars.

Gene Mapping, Cloning and Association Analysis for Salt Tolerance in Rice.

Soil salinization caused by the accumulation of sodium can decrease rice yield and quality. Identification of rice salt tolerance genes and their molecular mechanisms could help breeders genetically improve salt tolerance. We studied QTL mapping of populations for rice salt tolerance, period and method of salt tolerance identification, salt tolerance evaluation parameters, identification of salt tolerance QTLs, and fine-mapping and map cloning of salt tolerance QTLs. We discuss our findings as they relate to other genetic studies of salt tolerance association.

Correction to: Identification and salt tolerance evaluation of endophyte fungi isolates from halophyte plants

There was a mistake in the name of affiliation. It is written Bu Ali-Sina university, but it must be Bu-Ali Sina University ( the place of).

Comprehensive Evaluation of Salt Tolerance in Rice (Oryza sativa L.) Germplasm at the Germination Stage

Salt stress reduces the yield and quality of rice. It is of great significance to screen out salt-tolerant varieties for the development and utilization of saline land. The study was carried out on 114 rice varieties; first, seven varieties were selected and treated with different salt concentrations (0, 50, 85, 120, 155, 190, 225 mM), and seven traits, including germination energy, germination capacity, shoot length, root length, root number, plant fresh weight, and seedling vigor index, were measured. The salt concentration at which the sodium chloride injury index was 50% of the control was considered the optimal salt concentration. Second, 114 rice germplasms were carried out under an optimal salt concentration (120 mM). Then, principal component analysis, fuzzy function analysis, stepwise regression analysis, correlation analysis, and systematic cluster analysis were carried out on each parameter. There was a significant correlation between each parameter and the D-value, and the correlation coefficient between the seedling vigor index and D-value was the highest. D-value = − 0.272 + 1.335 × STI − SVI + 0.549 × STI − RN − 0.617 × STI-RL + 0.073 × STI − GE, R2 = 0.986. Using this equation, the sodium chloride tolerance of rice in the germination experiment could be quickly identified. This study showed that the seedling vigor index was a reliable parameter to identify the salinity tolerance of rice varieties. Five groups were obtained by classification at a Euclidean distance of 5. There were 8 highly salt-tolerant cultivars, 23 salt-tolerant cultivars, 42 cultivars with moderate salt tolerance, 33 salt-sensitive cultivars, and 8 highly salt-sensitive cultivars. In this study, we found that Riguang was the most salt-tolerant rice variety, and Xiangxuejing15 was the most salt-sensitive variety.

Evaluating salt tolerance in doubled haploid barley lines using a multivariable screening approach

Salt stress is one of the major environmental factors limiting cereal productivity in worldwide agriculture. Evaluating and selecting salt tolerant genotypes are an effective approach to overcome yield losses. This study aimed to characterize and compare phenotypic variability among doubled haploid (DH) barley lines and their parent under different salinity conditions (T1 = 0, T2 = 3, and T3 = 6 g.L −1 NaCl). The DH lines were produced by in vitro selection callus in a regeneration medium supplemented with 5 g.L −1 NaCl. Fifteen measured traits were assessed including physiological, biochemical, and agro-morphological traits. Biplot analysis was used to visualize the relationships among the studied traits and to evaluate the relative performance of each genotype. Pearson's correlation followed by stepwise and path analysis were then performed successively to identify appropriate criteria that most influence grain yield. The results showed a wide range of variation for the measured traits, indicating the existence of a phenotypic variation between the tested genotypes. Salinity significantly affected the parent more than the DH lines. Stepwise regression analysis indicated that 99% of the variation in grain yield was explained by K + /Na + ratio, number of fertile spikes per plant, number of grains per spike, plant height, and proline content. However, the path coefficient revealed that number of fertile spikes per plant and number of grains per spike were indicative of salt tolerance in barley. Based on stepwise and path analysis results, the tested genotypes were ranked using salt tolerance index. The salt tolerant DH lines could be recommended as novel genetic resources in breeding programs. • A set of agro-physiological and biochemical traits was used to differentiate salt tolerant genotypes between doubled haploid barley lines and their parent. • Salt stress caused significant increase in proline, Na + , and decrease K + , stomatal conductance, and chlorophyll contents. • Salt stress reduced significantly yield and yield components. • Fertile tiller number, number of grain per spike, and K + /Na + ratio were the major traits influencing grain yield. • The doubled haploid barley lines exhibited superiority in salinity tolerance compared with their parent.

Evaluation of salt tolerance in maize (Zea mays L.) at seedling stage through morphological characters and salt tolerance index

Evaluation of salt tolerance in maize (Zea mays L.) at seedling stage through morphological characters and salt tolerance index

Evaluation of Salt Tolerance in Italian Ryegrass at Different Developmental Stages

Soil salinity is one of the major abiotic stresses that continues to threaten plant growth and agricultural productivity. Screening germplasm with salinity tolerance is therefore necessary. This study was designed to evaluate salt tolerance based on the integrated tolerance index. Fifteen Italian ryegrass cultivars were used to evaluate the degree of genotypic variation in salt tolerance at the germination and vegetative growth stages of plant development. Evident variations in salt tolerance were observed at the germination stage under 255 mM NaCl treatment. Root growth rate, chlorophyll content, and germination rates played a vital role in determining salt tolerance. Based on combined attributes at the germination and vegetative growth stages, Gongniu, Chuangnong, Splendor, and Abundant were identified as the most tolerant cultivars. Furthermore, the constant crude protein, lower neutral detergent fiber, and acid detergent fiber contents were measured under salinity. Compared to the control, the cultivars Tetragold, Abundant, Splendor, Muyao, Harukaze, Tegao, Dongmu 70, and Doraian were identified to have high forage quality under salt stress. Finally, we selected Splendor and Abundant as the cultivars that expressed the highest degree of salt tolerance based on combined attributes related to germination, salt tolerance, and overall forage quality. In addition, gene expression analysis between salinity tolerant and sensitive cultivars revealed that the gene response to photosystem and carbohydrate synthesis may have played a mediating role in providing tolerance to salt stress.