Salt-tolerant Genotypes Research Articles

Screening Blackgram (Vigna mungo (L.) Hepper) Genotypes for Salt Tolerance at Germination and Seedling Stages

Aim: Salt stress negatively affects the growth and development of plants. An effective and important strategy to develop salinity tolerant crops is to harness the genetic diversity within the crop germplasm by identification of salinity tolerant genotype. The present study was carried out with an objective to screen blackgram genotypes (A31, DPU 968, KU 7720, LBG 787, PLU 621, TMV 1, Tutiminimum, VBG 18028, VBG 18032, and VBN 2) for salt tolerance at germination and seedlings stage and identification of saline tolerant blackgram genotype based on salt stress tolerance indices.
 Study Design: Factorial and arranged in a completely randomized design.
 Place and Duration of Study: Department of Crop Physiology, Tamil Nadu Agricultural University, Coimbatore; May-June 2022.
 Methodology: Using petriplate and roll towel techniques, blackgram seed germination indices and seedling growth indices such as germination percentage, germination index, mean germination time, seedling vigour index, shoot and root length, fresh and dry seedling weight, and stress tolerance indices were recorded. Two-way ANOVA, Principle Component Analysis (PCA) and Cluster Heat-map Analysis were used to analyze the data.
 Results: PCA indicates that salinity stress accounted for 86.2 percent of the variation, whereas the individual genotype contributes only 5.4 percent of the variation observed in germination and growth parameters that were studied in blackgram under control and 130mM NaCl salt stress conditions. Among the ten blackgram genotypes, stress tolerance index was highest for LBG 787 (0.831) followed by KU7720 (0.722). On the other side, the stress susceptible index was found to be lower for the blackgram genotype KU7720 (0.335) followed by LBG 787 (0.592), as compared to other genotypes screened. Cluster heat-map analysis for all the measured parameters revealed that blackgram genotype LBG 787 was clustered with PLU 621 and VBG 18028 and found to tolerate the salt stress level (130mM NaCl stress) compared to other blackgram genotypes.
 Conclusion: Observations indicate that the blackgram genotypes KU 7720, LBG 787, PLU 621 and VBG 18028 exhibit greater tolerance towards salinity during the germination and seedling growth stages.

Salinity Stress Tolerance in Potato Cultivars: Evidence from Physiological and Biochemical Traits.

Salinity stress is a major constraint to sustainable crop production due to its adverse impact on crop growth, physiology, and productivity. As potato is the fourth most important staple food crop, enhancing its productivity is necessary to ensure food security for the ever-increasing population. Identification and cultivation of salt-tolerant potato genotypes are imperative mitigating strategies to cope with stress conditions. For this purpose, fifty-three varieties of potato were screened under control and salt stress conditions for growth and yield-related traits during 2020. Salt stress caused a mean reduction of 14.49%, 8.88%, and 38.75% in plant height, stem numbers, and tuber yield, respectively in comparison to control. Based on percent yield reduction, the genotypes were classified as salt-tolerant (seven genotypes), moderately tolerant (thirty-seven genotypes), and salt-sensitive genotypes (nine genotypes). Seven salt-tolerant and nine salt-sensitive genotypes were further evaluated to study their responses to salinity on targeted physiological, biochemical, and ionic traits during 2021. Salt stress significantly reduced the relative water content (RWC), membrane stability index (MSI), photosynthesis rate (Pn), transpiration rate (E), stomatal conductance, and K+/Na+ ratio in all the sixteen genotypes; however, this reduction was more pronounced in salt-sensitive genotypes compared to salt-tolerant ones. The better performance of salt-tolerant genotypes under salt stress was due to the strong antioxidant defense system as evidenced by greater activity of super oxide dismutase (SOD), peroxidase (POX), catalase (CAT), and ascorbate peroxidase (APX) and better osmotic adjustment (accumulation of proline). The stepwise regression approach identified plant height, stem numbers, relative water content, proline content, H2O2, POX, tuber K+/Na+, and membrane stability index as predominant traits for tuber yield, suggesting their significant role in alleviating salt stress. The identified salt-tolerant genotypes could be used in hybridization programs for the development of new high-yielding and salt-tolerant breeding lines. Further, these genotypes can be used to understand the genetic and molecular mechanism of salt tolerance in potato.

Salinity-induced Changes In Growth, Physiology And Yield Of Soybean Genotypes

Soybean (Glycine max L.) is mostly grown in the coastal region of Bangladesh, where salinity is a threat for potential harvest. So far there is no salt tolerant variety. In order to extricate high salt tolerant soybean genotypes, 13 selected advanced soybean lines, namely BD 2342, AGS 313, G 00207, Galarsum, G 00209, G 00343, G 00028, G 00221, G 00283, AGS 95, G 00062, G 00041 and BD 2330 along with two varieties viz. BU Soybean 2 and Shohag were grown in pots under polyvinyl house at BSMRAU, Gazipur during February to June 2021 following completely randomized design (CRD) with three replications. The plants were exposed to seawater of electrical conductivity (EC) of 5 dSm-1 and 10 dSm-1 from 2nd trifoliate stage till harvest, where control pots were irrigated with tap water (0.3 dSm-1). Results indicated that there was no significant variation in days to first flowering but significant variation was observed in maturity duration among the genotypes. In saline conditions BD 2330, G 00028 and AGS 313 survived longer days which were 96.36%, 80.29%, and 79.53% days to control at 10 dSm-1, respectively compared to other genotypes. Plants of other genotypes died earlier before reaching maturity, especially at 10 dSm-1. The genotype AGS313 expressed maximum leaf relative water content (RWC) at 5 dSm-1 salinity (97.51% of control), while BD2330 showed the highest RWC at 10 dSm-1 salinity (94.76%). The SPAD value showed stable or an increasing trends in BD 2330, AGS 313 and G 00028, where it was in decreasing trend in other genotypes under saline conditions. Unexpectedly, the leaf K-Na ratio did not show any significant relationship with the salt-tolerance among the genotypes. In case of number of filled pods/plant BD2330 produced the maximum (23.33) at 5 dSm-1 salinity, while the genotype AGS313 showed the highest (16.0) at 10 dSm-1 salinity. Genotypes other than BD2330, AGS313 and G00028 did not perform well in pod set, 100-seed weight and grain yield/plant under saline conditions, even at 5 dSm-1. However, even at the highest salinity (10 dSm-1) the genotypes G00028, BD2330 and AGS313 produced 2.0, 1.9 and 1.83 g/plant seeds, respectively. Whereas, most of the genotypes did not produce any seed at 10 dSm-1. It may be concluded that the genotypes BD2330, AGS313 and G00028 were relatively salt tolerant than other tested genotypes, and can be used as potential genetic resources for further field trials. Ann. Bangladesh Agric. (2022) 26 (1) : 29-48

Comparison of the Yield of Different Rice Varieties Treated with l-Ascorbic Acid on Site-Specific Saline Soil

We conducted a comparative study of the effect of vitamin C (l-ascorbic acid) treatment on the yield of selected rice varieties grown in site-specific saline soil; the study area was Paluh Merbau, which is situated on the east coast of North Sumatra and has a salinity of 5.9 dS/m. Salinity causes osmotic, salt-specific, and oxidative stress, which negatively affects crop yields. The aim of this study was to compare the effects of l-ascorbic acid treatment on the yield parameters of eight varieties of rice grown on saline soil. This study was based on a randomized block design with two factors. The first factor was the rice variety (Ciherang, IR 64, Lambur, Batanghari, Banyuasin, IR 42, Inpara 10, and Margasari), and the second factor was the concentration of l-ascorbic acid (0, 500, 1,000, or 1,500 mg/L). The number of empty grains per panicles, grain weight per clump, and number of filled grains per panicles increased as the concentration of l-ascorbic acid increased. l-Ascorbic acid at a concentration of 1,500 mg/L exhibited the best results, and the grain weight of Banyuasin and Batanghari varieties was 33.22 and 30.18 g, respectively; however, there was no significant difference in grain weight between the varieties. Batanghari and Ciherang were the most salt-tolerant genotypes, with a high ability to produce high number of filled grains compared to other varieties. l-Ascorbic acid treatment can promote the yields of rice varieties grown under salinity stress.

Comparative Plasticity Responses of Stable Isotopes of Carbon (δ13C) and Nitrogen (δ15N), Ion Homeostasis and Yield Attributes in Barley Exposed to Saline Environment.

Salinity is a major threat to agricultural productivity worldwide. The selection and evaluation of crop varieties that can tolerate salt stress are the main components for the rehabilitation of salt-degraded marginal soils. A field experiment was conducted to evaluate salinity tolerance potential, growth performance, carbon (δ13C) and nitrogen isotope composition (δ15N), intrinsic water use efficiency (iWUE), harvest index, and yield stability attributes in six barley genotypes (113/1B, 59/3A, N1-10, N1-29, Barjouj, Alanda01) at three salinity levels (0, 7, and 14 dS m−1). The number of spikes m−2 was highest in Alanda01 (620.8) while the lowest (556.2) was exhibited by Barjouj. Alanda01 produced the highest grain yield (3.96 t ha−1), while the lowest yield was obtained in 59/3A (2.31 t ha−1). Genotypes 113/1B, Barjouj, and Alanda01 demonstrate the highest negative δ13C values (−27.10‰, −26.49‰, −26.45‰), while the lowest values were obtained in N1-29 (−21.63‰) under salt stress. The δ15N was increased (4.93‰ and 4.59‰) after 7 and 14 dS m−1 as compared to control (3.12‰). The iWUE was higher in N1-29 (144.5) and N1-10 (131.8), while lowest in Barjouj (81.4). Grain protein contents were higher in 113/1B and Barjouj than other genotypes. We concluded that salt tolerant barley genotypes can be cultivated in saline marginal soils for food and nutrition security and can help in the rehabilitation of marginal lands.

Somatic Embryos Induction of East Kalimantan Local Rice (Oryza sativa L.) Cultivars and In Vitro Selection Against Salinity

Soil salinity is one major environmental constraint on rice production, especially in coastal areas. The development of salt-tolerant genotypes is considered to be the most effective breeding strategy to overcome the constraint. This study aims to induce somatic embryos formation of East Kalimantan local rice cultivars and to obtain tolerant somatic embryos under saline condition via in vitro selection. Four commonly cultivated local rice cultivars, namely Buyung, Siam, Ketalun Tawar and Serai Gunung, were used in this study. The somatic embryos were produced using three different plant growth regulator (PGR) compositions. The salinity tolerance level of somatic embryos was induced by in vitro selection in salt toxicity medium containing 0 mM; 50 mM; 100 mM; 150 mM; 200 mM NaCl. The best medium for somatic embryogenesis contains 1 mg/l 2,4-D + 0.5 m/l BAP, resulting the highest percentage of cream and white non-compact callus on the tested cultivars. More than 70% of the somatic embryos were tolerant against salinity (NaCl 200 mM). However, only somatic embryos derived from Serai Gunung could regenerate into normal plantlets.

Evaluation of Green Super Rice Lines for Agronomic and Physiological Traits under Salinity Stress.

Rice (Oryza sativa) is an important staple food crop worldwide, especially in east and southeast Asia. About one-third of rice cultivated area is under saline soil, either natural saline soils or irrigation with brackish water. Salinity stress is among the devastating abiotic stresses that not only affect rice growth and crop productivity but also limit its cultivation area globally. Plants adopt multiple tolerance mechanisms at the morphological, physiological, and biochemical levels to tackle salinity stress. To identify these tolerance mechanisms, this study was carried out under both a controlled glass house as well as natural saline field conditions using 22 green super rice (GSR) lines along with two local varieties (“IRRI 6 and Kissan Basmati”). Several morpho-physiological and biochemical parameters along with stress-responsive genes were used as evaluation criteria under normal and salinity stress conditions. Correlation and Principal Component Analysis (PCA) suggested that shoot-related parameters and the salt susceptible index (SSI) can be used for the identification of salt-tolerant genotypes. Based on Agglomerative Hierarchical Cluster (AHC) analysis, two saline-tolerant (“S19 and S20”) and saline-susceptible (“S3 and S24”) lines were selected for further molecular evaluation. Quantitative RT-PCR was performed, and results showed that expression of 1-5-phosphoribosyl -5-5-phosphoribosyl amino methylidene amino imidazole-4-carboxamide isomerase, DNA repair protein recA, and peptide transporter PTR2 related genes were upregulated in salt-tolerant genotypes, suggesting their potential role in salinity tolerance. However, additional validation using reverse genetics approaches will further confirm their specific role in salt tolerance. Identified saline-tolerant lines in this study will be useful genetic resources for future salinity breeding programs.

Role of the type-B authentic response regulator gene family in fragrant rice under alkaline salt stress.

Globally, rice is being consumed as a main staple food and faces different kinds of biotic and abiotic stresses such drought, salinity, and pest attacks. Through the cytokinin signaling, Type-B authentic response regulators (ARR-Bs) respond positively towards the environmental stimuli. ARR-Bs are involved in abiotic stress tolerance and plant development but their molecular mechanisms in fragrant rice are still not fully explored. The current study showed the genome-wide characterization of OsARR-B genes under alkaline salt stress. Results showed that in total, 24 OsARR-B genes were found and divided into four subgroups on the basis of a phylogenetic analysis. These genes were located on all rice chromosomes except 8 and 10. Analysis of gene duplications, gene structure, cis-elements, protein-protein interactions, and miRNA were performed. Gene ontology analysis showed that OsARR-B genes are involved in plant development through the regulation of molecular functions, biological processes, and cellular components. Furthermore, 117 and 192 RNA editing sites were detected in chloroplast and mitochondrial genes, respectively, encoding proteins of OsARR-B. In chloroplast and mitochondrial genes, six and nine types of amino acid changes, respectively, were caused by RNA editing, showing that RNA editing has a role in the alkaline salt stress tolerance in fragrant rice. We also used a comparative transcriptome approach to study the gene expression changes in alkaline tolerant and susceptible genotypes. Under alkaline salt stress, OsARR-B5, OsARR-B7, OsARR-B9, OsARR-B10, OsARR-B16, OsARR-B22, and OsARR-B23 showed higher transcript levels in alkaline salt tolerant genotypes as compared to susceptible ones. Quantitative RT-PCR showed upregulation of gene expression in the alkaline tolerant genotypes under alkaline stress. Our study explored the gene expression profiling and RESs of two rice contrasting genotypes, which will help to understand the molecular mechanisms of alkaline salt tolerance in fragrant rice.

The characterization of wheat genotypes for salinity tolerance using morpho-physiological indices under hydroponic conditions

Salinity affects plant growth, development, yield, and is a big challenge for wheat growth across the globe. Possible feasible solution is creation of salt-tolerant material, genetic variation is a criterion to developing genetically superior individuals. To assess the genetic variation for salt tolerance, nationally and internationally-derived 81 wheat genotypes were selected and evaluated in 0- and 150-mM salt in nutritional culture at seedling stage. Results indicate that salinity levels reveal significant (p ≤ 0.01) differences for fresh root weight (RW), shoot length (SL), fresh shoot weight (SW), total plant length (TL), total fresh weight (TW), root/shoot weight ratio (RSWR), root/shoot length ratio (RSLR), and relative growth rate for weight (RGR-Wt). While, there was no difference for root length (RL). Hierarchical Clustering and Pairwise correlation analysis showed TW, RGR-Wt, SL, SW, and RW were positively correlated among themselves, whereas RL had poor correlations with all the traits except TL and RSLR. Hence, selection of SL can improve the performance of other parameters. Based on PCA analysis, SW and RGR-Wt were the major discriminative components for wheat genotypes. Present study explained that shoot related parameters could be used as a selection criterion to categorize salt-tolerant genotypes. Outperforming genotypes 1104 and 1106 in saline conditions could be used as parents in creation of salt-tolerant wheat genotypes, and parameters such as SL, SW, TW, and RGR-Wt for early screening will be important for creating salt-tolerant and high yielding wheat genotypes.

EVALUATION OF GUAVA GERMPLASM FOR GROWTH, QUALITY AND YIELD ATTRIBUTES SUITABLE UNDER SODIC SOIL CONDITIONS

Guava (Psidium guajava L.) popularly known as the "Apple of the Tropics", has gained considerable prominence on account of its high nutritive value, availability at moderate prices and pleasant flavour. It is a rich source of vitamin C and pectin, moderately good source of calcium and a fair source of phosphorus. The study was carried out to evaluate the guava (Psidium gujava L.) germplasm for growth, yield and quality under sodic soil condition. Totally 31 accessions of guava germplasm were collected and planted in RBD with 4 replications at Orchard, Horticultural College & Research Institute for Women, Tamil Nadu Agricultural University, Trichy and evaluated for 5 years (2014 to 2018) under sodic condition. Growth observations on plant height (m), trunk circumference (cm), plant spread (E – W) (m) and plant spread (N – S) (m) and tree volume (cm3 ) were recorded. Further, yield and quality attributes viz., number of fruits tree-1, fruit length, fruit diameter, average fruit weight, fruit yield tree-1, pulp colour, flesh thickness, rind thickness and TSS were also recorded. Among the guava germplasm, “Surka Chitti Natputani” was found to be vigorous in growth habit followed by “Mirzapur seedling” whereas dwarfness and erect growth were observed in “Cheeni guava”. The accession “Nasik” recorded the highest fruit yield (26.285 kg tree-1) followed by “Mirzapur Seedling” (24.277kg tree-1). Dessert quality attributes viz., rind thickness, soft seed and total soluble solid were found to be best in “Allahabad Safed”. The present studies impart knowledge on morphological, quantitative variation and quality parameters of guava fruits and can be useful for producers, breeders, and processors. The salt tolerant genotypes having the capable of maintaining osmotic potential and providing more food materials.

Salt tolerance of hybrid baby corn genotypes in relation to growth, yield, physiological, and biochemical characters

Soil salinity is a major global concern for sustainable crop production, and proper screening of crop genotypes against salt stress should be a major consideration before recommending a genotype for field cultivation. Germination, growth, yield, physiological, and biochemical responses of 11 hybrid baby corn genotypes (Kasetsart 3, PAC 271, PAC 321, PAC 571, SG 17 Super, CP B468, CP B905, WS 111, WS 9103, Chang Daeng 18, and HY 074656) to five levels of NaCl-induced salinity (0.7 [control], 3, 6, 9, and 12 dS m–1) were evaluated in a germination trial in petri dishes followed by a polyhouse study to assess genotypic variation of baby corn genotypes in salinity tolerance. Data on various germination traits, growth, yield, physiological, and biochemical parameters were collected. Increasing salinity level above 6 dS m–1 was equally detrimental for germination and growth of all tested genotypes. Germination response of Chang Daeng 18 genotype to salt stress was the poorest (22.2% germination rate and 7.7% mean daily germination). Growth, yield, physiological, and sodium (Na+) accumulation data revealed that SG 17 Super genotype was the most susceptible to salt stress, whereas PAC 571 was the most tolerant. SG 17 Super had 28% lower shoot dry matter, 54% lower cob yield, 25% less membrane stability index, and 158% more Na+ accumulation compared with PAC 571. All other genotypes were between slightly salt-tolerant to moderately salt-tolerant category, which was also verified by the Hierarchical cluster analysis. Physiological and biochemical parameters, such as free proline, membrane electrolyte leakage, and membrane stability index, as well as ion accumulation parameter, such as Na+, were the most representative of salt stress. Salinity reduced leaf greenness (SPAD value), while net photosynthetic rate, stomatal conductance, and transpiration rate were not affected. Na+ exclusion and higher K+/Na+ ratio in leaves of baby corn genotypes correlated well with their higher salinity tolerance, and greater K+/Na+ discrimination was shown by salt-tolerant genotypes. The relative susceptibility of baby corn genotypes to salinity should be taken into consideration for plant breeding programs. The selected salt-tolerant baby corn genotypes have potentials for cultivation in salt-affected soils for better productivity.

High-LD SNP markers exhibiting pleiotropic effects on salt tolerance at germination and seedlings stages in spring wheat

Key messageSalt tolerance at germination and seedling growth stages was investigated. GWAS revealed nine genomic regions with pleiotropic effects on salt tolerance. Salt tolerant genotypes were identified for future breeding program.With 20% of the irrigated land worldwide affected by it, salinity is a serious threat to plant development and crop production. While wheat is the most stable food source worldwide, it has been classified as moderately tolerant to salinity. In several crop plants; such as barley, maize and rice, it has been shown that salinity tolerance at seed germination and seedling establishment is under polygenic control. As yield was the ultimate goal of breeders and geneticists, less attention has been paid to understanding the genetic architecture of salt tolerance at early stages. Thus, the genetic control of salt tolerance at these stages is poorly understood relative to the late stages. In the current study, 176 genotypes of spring wheat were tested for salinity tolerance at seed germination and seedling establishment. Genome-Wide Association Study (GWAS) has been used to identify the genomic regions/genes conferring salt tolerance at seed germination and seedling establishment. Salinity stress negatively impacted all germination and seedling development parameters. A set of 137 SNPs showed significant association with the traits of interest. Across the whole genome, 33 regions showed high linkage disequilibrium (LD). These high LD regions harbored 15 SNPs with pleiotropic effect (i.e. SNPs that control more than one trait). Nine genes belonging to different functional groups were found to be associated with the pleiotropic SNPs. Noteworthy, chromosome 2B harbored the gene TraesCS2B02G135900 that acts as a potassium transporter. Remarkably, one SNP marker, reported in an early study, associated with salt tolerance was validated in this study. Our findings represent potential targets of genetic manipulation to understand and improve salinity tolerance in wheat.

Identification of differentially expressed genes in salt-tolerant oilseed sunflower (Helianthus annuus L.) genotype by RNA sequencing.

Sunflower (Helianthus annuus L.) is widely planted as an oilseed crop worldwide. Salt stress is one of the major abiotic stresses that negatively affect crop growth and productivity. To counter the negative impact of salt stress, plants have developed avoidance and tolerance mechanisms. Developing salt-tolerant genotypes requires understanding the molecular basis of adaptive mechanisms in depth. Although using model plants i.e., Arabidopsis has improved our understanding of salt tolerant mechanisms, the relative impotence and regulation mechanisms vary among plant species due to differences in genetic and metabolic backgrounds. On the other hand, sunflower is a highly polymorphic plant due to its cross-pollinated behavior which provides different salt-tolerant genotypes available for comparative analyses. In order to gain a better view of molecular mechanisms involved in salt tolerance in sunflower, RNA sequencing analysis was realized by evaluating a tolerant genotype (AS5305) with two biological replicates under control and salt stress conditions in a controlled environment. Salinity stress was applied from NaCl resource at the 8-leaf stage and samplings were done at 24h post salt stress application. Sequencing data were analyzed using tuxedo software suite. Blast2GO software and the KEGG database were used to identify the functional tasks of each of the assembled transcripts. Analysis of genes with robust expression (i.e., with FPKM > 1 in at least one sample) revealed a total of 121 significantly expressed genes between the saline-stressed and control samples. The differential expression of 11 genes was confirmed by real-time PCR. In the following, the cDNA of MYB44 as one of the selected candidate genes involved in salt tolerance was isolated, cloned, and sequenced for comparison. Overall, the results of the current study may pave the way for the accurate selection of genes involved in salinity to be used in molecular-genetics-assisted breeding programs. In addition, making use of the identified genes may help relieve the damages arising from the salt stress in sunflowers.

Genetic Conservation of CBS Domain Containing Protein Family in Oryza Species and Their Association with Abiotic Stress Responses.

Crop Wild Relatives (CWRs) form a comprehensive gene pool that can answer the queries related to plant domestication, speciation, and ecological adaptation. The genus ‘Oryza’ comprises about 27 species, of which two are cultivated, while the remaining are wild. Here, we have attempted to understand the conservation and diversification of the genes encoding Cystathionine β-synthase (CBS) domain-containing proteins (CDCPs) in domesticated and CWRs of rice. Few members of CDCPs were previously identified to be stress-responsive and associated with multiple stress tolerance in rice. Through genome-wide analysis of eleven rice genomes, we identified a total of 36 genes encoding CDCPs in O. longistaminata, 38 in O. glaberrima, 39 each in O. rufipogon, O. glumaepatula, O. brachyantha, O. punctata, and O. sativa subsp. japonica, 40 each in O. barthii and O. meridionalis, 41 in O. nivara, and 42 in O. sativa subsp. indica. Gene duplication analysis as well as non-synonymous and synonymous substitutions in the duplicated gene pairs indicated that this family is shaped majorly by the negative or purifying selection pressure through the long-term evolution process. We identified the presence of two additional hetero-domains, namely TerCH and CoatomerE (specifically in O. sativa subsp. indica), which were not reported previously in plant CDCPs. The in silico expression analysis revealed some of the members to be responsive to various abiotic stresses. Furthermore, the qRT-PCR based analysis identified some members to be highly inducive specifically in salt-tolerant genotype in response to salinity. The cis-regulatory element analysis predicted the presence of numerous stress as well as a few phytohormone-responsive elements in their promoter region. The data presented in this study would be helpful in the characterization of these CDCPs from rice, particularly in relation to abiotic stress tolerance.

Assessment of maize genotypes for salt tolerance based on physiological indices

Assessment of maize genotypes for salt tolerance based on physiological indices

Effect of Gypsum & Bio-compost Applications on Relative Water Content in Rice Genotypes under Sodic Soil

Sodic soils have immense productivity potential, if managed through proper technology interventions. Bio-compost is prepared by composting pressmud and gypsum received from waste material of mining can be used to reclaim sodic soils. Field experiments were conducted during the June-November of 2018 and 2019 at the ICAR - Indian Agricultural Research Institute, Sub Regional Station, Pusa (Samastipur), Bihar. Experiment was laid out in split-plot design with four treatments i.e. T1(Control plots), T2 (Gypsum@100% G.R. amended plots), T3(Gypsum @ 50% G.R.+ Bio-compost @ 2.5 tha-1 amended plots), and T4(Biocompost @ 5.0 tha-1 amended plots) in main plots and ten rice genotypes G1(Suwasini), G2(Rajendra Bhagwati), G3(Boro-3), G4(Rajendra Neelam), G5(CSR-30), G6(CSR-36), G7(CR-3884-244-8-5-6-1-1), G8(CR-2851-SB-1-2-B-1), G9(CSR-27), and G10 (Pusa-44) in sub plots and replicated thrice. The promising results reveal that the mean of leaf relative water content at pre-flowering stage in the salt-tolerant genotypes ranged from 69.47 % to 82.20 % during 2018 and 69.52 % to 82.24 % during 2019. The mean of leaf relative water content at grain filling stage in all the genotypes varied between 77.55 % to 85.45 % during 2018 and 75.49 % to 85.16 % during 2019. Soil amendments and genotypes interaction was found significantly in both the years at grain filling stage.

Salt stress responses and SNP-based phylogenetic analysis of Thai rice cultivars.

Genetic diversity is important for developing salt-tolerant rice (Oryza sativa L.) cultivars. Certain Thai rice accessions display salt tolerance at the adult or reproductive stage, but their response to salinity at the seedling stage is unknown. In this study, a total of 10 rice cultivars/line, including eight Thai cultivars and standard salt-tolerant cultivar and susceptible line, were screened using a hydroponic system to identify salt-tolerant genotypes at the seedling stage. Different morphophysiological indicators were used to classify tolerant and susceptible genotypes. Phylogenetic analyses were performed to determine the evolutionary relationships between the cultivars. Results showed that 'Lai Mahk', 'Jao Khao', 'Luang Pratahn', and 'Ma Gawk' exhibited salt stress tolerance comparable with the standard salt-tolerance check 'Pokkali'. Whole-exome single-nucleotide polymorphism (SNP)-based phylogenetic analysis showed that the Thai rice cultivars were monophyletic and distantly related to Pokkali and IR29. Lai Mahk and Luang Pratahn were found closely related when using the whole-exome SNPs for the analysis. This is also the case for the analysis of SNPs from 164 salt-tolerance genes and transcription regulatory genes. The tolerant cultivars shared the same haplotype for 16 genes. Overall, the findings of this study identified four salt-stress-tolerant Thai rice cultivars, which could be used in rice breeding programs for salinity tolerance.

Salt tolerance of seven genotypes of zoysiagrass (<i>Zoysia</i> spp.)

Seven zoysiagrass genotypes were evaluated for salt tolerance in a greenhouse study. The plant materials included <italic>Zoysia matrella</italic> 'Diamond', <italic>Z. japonica</italic> 'Palisades', three <italic>Z</italic>. <italic>matrella</italic> × <italic>Z. japonica</italic> hybrids DALZ 1701, DALZ 1713, and 'Innovation', and two <italic>Z.</italic> <italic>minima</italic> × <italic>Z. matrella</italic> hybrids (DALZ 1309 and 'Lazer'). Treatments included a control (nutrient solution) and two saline treatments representing moderate and high salt levels. The electrical conductivity (EC) was 1.3 dS m⁻¹ for control and moderate (EC5) and high salinity (EC10) were 5.0 and 10.0 dS m⁻¹, respectively. At the end of eight-week treatments, the relative (percent control) shoot dry weight (DW) was greatest in 'Diamond' in EC10, and the relative root DW was greatest in DALZ 1309 in EC5. A cluster analysis based on the relative tissue dry weight identified 'Diamond', DALZ 1309, and DALZ 1713 as the most salt tolerant genotypes. Additionally, the green leaf area (GLA) index of 'Diamond' and DALZ 1713 were 98.8% and 100%, respectively, indicating excellent visual appearance under high salt levels. Bi-weekly clipping DW showed that ‘Diamond’ continued to produce biomass throughout the duration of the study under the EC10 treatment. Sodium (Na⁺) and chloride (Cl⁻) content in the shoot tissue of the seven turfgrass genotypes indicated that lower concentrations corresponded to greater salt tolerance indicating exclusion of Na⁺ and Cl⁻ from the shoot tissue. Taken together, the genotypes 'Diamond' and DALZ 1713 were determined to be the most salt tolerant and recommended for use in areas with high soil or water salinity.

Biochemical, physiological, and growth evaluation of different chickpea genotypes under varying salinity regimes.

Biochemical and physiological parameters, growth, and yield of field crops especially salt sensitive crops like chickpea are affected adversely by salinity in arid to semi-arid regions. To investigate the effect of different salinity levels on growth, biochemical and physiological parameters of chickpea genotypes, a pot experiment following CRD, two factor factorial design, was conducted in the glasshouse at the Institute of Biotechnology and Genetic Engineering, The University of Agriculture, Peshawar, Pakistan. Ten (10) kg of soil was filled in each pot and salinity levels were maintained @ S0= 0 mM NaCl, S1= 50 mM NaCl, S2= 100 mM NaCl and S3= 150 mM by applying NaCl and 5 genotypes of chickpea (KK-2, Bhakkar-2011, Bittle-98, Punjab-2008, and CM-98) were used. At crop maturity, growth parameters, physiological, biochemical, and ionic parameters were measured using standard analysis procedures. Salinity reduced the growth and yield of all genotypes, but the rate of decrease was different among the genotypes tested. From the results, a decrease in K concentration, K/Na ratio, transpiration rate, stomatal conductance, N, and P was observed in all genotypes with the increase in salinity. An increase in salinity level increased the proline content (35.45%), crude protein (42%), H2O2 (19%), lipid peroxidation (62%), carbohydrates (23.22%), and Na+ concentration (137%). The highest level of salinity, 150 mM NaCl has exhibited the highest salinity stress in all parameters. Genotype KK-2 and Bhakkar-11 showed a lower rate of relative decrease in yield (4.5 and 12%), K+/Na+ ratio (23.34 and 11.47%), and K+ concentration (7.9 and 11%), respectively, and the lowest relative increase in Na+ accumulation (20.3 and 0.48%), @ 50 mM salinity compared to control. Genotype KK-2 and Bhakkar-11 proved better @ 50mM salinity. The findings suggest that the critical level of the salinity must be kept in mind and the salt-tolerant genotypes should be cultivated in salt affected soils.

Effect of relative water content in rice genotypes after gypsum and bio-compost amended sodic soil

Sodic soils have immense productivity potential, if managed through proper technology interventions. Biocompost is prepared by composting pressmud (a sugar industry byproduct) received from cane juice filtration and spent wash received from distilleries through microbial aerobic decomposition and gypsum received from waste material of mining can be used to reclaim sodic soils. Field experiments were conducted during the kharif season of 2018 and 2019 at the ICAR-Indian Agricultural Research Institute, Sub Regional Station, Pusa (Samastipur). The promising results revealed that the mean of leaf relative water content at pre-flowering stage in the salt-tolerant genotypes ranged between 69.47 to 82.20 per cent during 2018 and 69.52 to 82.24 per cent during 2019. The mean of leaf relative water content at grain filling stage in all the genotypes varied between 77.55 to 85.45 per cent during 2018 and 75.49 to 85.16 per cent during 2019. Soil amendments and genotypes interaction were found significant in both the years at grain filling stage.