Top PDF TOLERANCE OF SOME BARLEY VARIETIES TO SALT STRESS AT SEEDLING STAGE

TOLERANCE OF SOME BARLEY VARIETIES TO SALT STRESS AT SEEDLING STAGE

TOLERANCE OF SOME BARLEY VARIETIES TO SALT STRESS AT SEEDLING STAGE

TOLERANCE OF SOME BARLEY VARIETIES TO SALT STRESS AT SEEDLING STAGE 311 171 while in remaining varieties the growth has been invariably decreased with increase in salini[r]

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Screening Some Accessions Of Lentil (Lens Culinaris M.) For Salt Tolerance At Germination And Early Seedling Stage In Eastern Ethiopia

Screening Some Accessions Of Lentil (Lens Culinaris M.) For Salt Tolerance At Germination And Early Seedling Stage In Eastern Ethiopia

Salinity is a continuing problem in the arid and semi-arid tracts of the world. It could be alleviate during irrigation management and/or crop management. However, the former approach is outdated and very expensive. Nevertheless, the latter is economical as well as efficient and it enables to produce salt tolerant crop lines. However, prior to that there is a need to confirm the presence of genetically based variation for salt tolerance among different species or varieties of a particular crop at different growth stages. The presence of genetic variation offers a basic tool for evaluating effect of salinity on lentil accessions and to overcome the presence of large number of variation for relatively salt tolerant lentil accession and it will appreciated to find accession with gene tolerant to salinity. Screening of salinity tolerance under field condition involves many environmental factors that affect genetic and phenotypic expression of accessions. Hence, controlled environment, Laboratory and greenhouse screening method indicate to be an ideal method to screen large amount of accessions with less efforts and accurately. Thus, the correct and clear expression of Lentil accessions for salt tolerant can be evaluated by this method using different NaCl level. The findings of this work confirmed that response of lentil accession to salinity show significant variation as their expose to different salinity level. The result explain that most out that all of the morpho-physiological and yield and yield related traits considered were significantly decreased with higher levels of salinity. Out of twelve lentil accession, accession 36120, 36004 and 9235 performed well under salt stress conditions in most of the parameter for both laboratory and greenhouse experiment as result those accession were recommended to be sown in saline condition.
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Genetic Structure of Salinity Tolerance in Rice at Seedling Stage

Genetic Structure of Salinity Tolerance in Rice at Seedling Stage

justification of 15.2% of the phenotype variation (Table 1 and 2). Under normal conditions, 1 QTL was identified on chromosome 4 for sodium root concentrations (NaRN). This QTL explained 12.3% of phenotypic variation and was located at an interval of RM280-ISSR11-4. In terms of salt stress, 6 QTLs were located on chromosomes 1, 2, 3, 9 and 10 for sodium root concentrations (NaR) (Fig. 1). The qNaR-3 had a justification of more than 20% for a phenotypic variance. This QTL was located at the distance between the markers of RM143- ISSR11-2. The effect of this QTL was -6.305, and the alleles of parents of ATM reduced this trait (Table 1 and 2). Under normal conditions, 5 QTLs for potassium stem (KSHN) were detected on chromosomes of 2, 3, 5, 6 and 8. The qKSHN-2 was able to justify 18.2% of the phenotypic variance of the trait. This QTL was closed to the RM300 marker and had an additive effect of 35.3. In salinity stress conditions, 6 QTLs were identified on chromosomes of 1, 2, 3, 4 and 8. The qKSH-1 and qKSH-4 indicated more than 20% of the phenotypic variance of the trait. These QTLs had a positive additive effect of 3.558 and 4.807mg/g, respectively (Table 1 and 2). In salt stress conditions, 3 QTLs for root potassium (KR) were identified on chromosomes of 2 and 7. qKR-2a, qKR-2b and qKR-7 were close to the ISSR5-3, ISSR12-2, and ISSR5-4 markers, respectively, and justified 9.9%, 12.4%, and 13.6% of the phenotypic variance of the attribute. Normally, this QTL attribute was not detected (Table 1
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Characterizing the Saltol quantitative trait locus for salinity tolerance in rice

Characterizing the Saltol quantitative trait locus for salinity tolerance in rice

Farmers have grown traditional rice landraces adapted to salt-affected areas for generations despite their numerous undesirable traits, including long duration, low yield, and poor grain quality. Some of these landraces possess remarkable tolerance to salt stress through a complex set of physiological mechanisms, including sodium exclusion, higher tissue tolerance by compartmenting salts into the apoplasts, effective sequestration of toxic salts into older tissues, stomatal responsiveness, and upregulating the antioxidant system during stress (Yeo and Flowers 1986; Ismail et al. 2007; Moradi and Ismail 2007). Moreover, tolerance during seedling stage seems to correlate poorly with tolerance during reproduction, suggesting different sets of traits are probably involved at each stage (Moradi et al. 2003). Despite this complexity, most salt-tolerant cultivars seem to posses only a few of these mechanisms, signifying the prospects for developing highly tolerant rice varieties through combining superior alleles of genes controlling these traits. Recent advances in molecular biology and genomics have led to a more detailed understanding of the genes and pathways involved in the salt stress response in rice, including those involved in ion transport and homeostasis, osmoregulation, and oxidative stress protection (Blumwald et al. 2000; Mäser et al. 2002; Garciadeblás et al. 2003; Chinnusamy et al. 2004; Horie and Schroeder 2004; Nakayama et al. 2005; Bohnert et al. 2006; Rodriguez-Navarro and Rubio 2006; Sahi et al. 2006; Martinoia et al. 2007; Munns and Tester 2008; Singh and Flowers 2010)
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QTL MAPPING FOR SALINITY TOLERANCE AT SEEDLING STAGE IN RICE

QTL MAPPING FOR SALINITY TOLERANCE AT SEEDLING STAGE IN RICE

plants with extreme phenotype for salinity stress response, i.e. tolerant and sensitive, were used for selective genotyping based on of visual seedling stage salt tolerance score on 1 to 9 scales where lower number indicates tolerance. Total two hundred and sixty SSR and two EST markers, selected at 5 Mb intervals within the rice genome were used for parental polymorphism survey (IRGSP, 2005). In SalTol QTL region of chromosome 1 (Bonilla et al., 2002) we used 10 additional markers that were tightly-linked to that QTL. Finally 90 makers were found polymorphic
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63. Evaluation of wheat varieties to salt stress (NaCl) for seed germination and early seedling growth under laboratory conditions

63. Evaluation of wheat varieties to salt stress (NaCl) for seed germination and early seedling growth under laboratory conditions

Salinity tolerance during germination and early seedling growth was evaluated of four wheat varieties under four salinity (NaCl) levels that included Control (distilled water) 0, 9, 12 and 16 dSm -1 . The seeds of four wheat varieties including Imdad-2005, Mahran-89, TJ-83 and TD- 1 were sown under various NaCl levels in Petri dishes. The trial was performed at Seed Testing Laboratory, Department of Agronomy, Sindh Agriculture University, Tandojam Pakistan, following completely randomized design with three replications. The results showed that different salt stress (NaCl) levels had significant effects on germination (%), shoot and root length (cm), shoot and root water content (%), shoot and root fresh weight (g) and shoot and root dry weight (g) of wheat varieties. Among varieties, Imdad-2005 showed tolerance against salt stress for all parameters as compared to other varieties. The Imdad-2005 produced maximum mean germination (93.7%), shoot and root length (14.8 cm and 9.3 cm), shoot and root RWC (80.1 % and 86.2%), shoot and root fresh weight (2.3 g and 1.5 g) and heaviest shoot and root dry weight (0.28 g and 0.13 g). However, for NaCl levels, maximum germination (96.2 %), shoot and root length (15.5 cm, 10.7 cm), shoot and root water content (86.4 %, 87.0%), shoot and root fresh weight (2.3 and 1.5 g) and highest shoot and root dry weight (0.28 g and 0.13 g) was noted at control, where seeds were on sown by using distilled water.
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Development of sodicity tolerant rice varieties through marker assisted backcross breeding

Development of sodicity tolerant rice varieties through marker assisted backcross breeding

The Exchangeable Sodium Per cent of the experiment plot was 35 and the pH was 9.5 and hence the soil was sodic and alkaline in nature. During Kharif, 2014, the raised beds were formed with 15 cm height and the pre-germinated seeds of 42 NILs were sown in three rows (1m length) in each of five replications adopting Randomised Block Design. The probable error due to soil heterogeneity was minimized because of randomization of entries and with five replications. In each row 30 shallow holes were made at equal distances and two seeds were sown per one hole. At two leaved stage one seedling was pulled out from each hill and only one seedling was maintained per hill. The seeds of salt tolerant check FL 478 and salt sensitive check ADT 43 were raised in between every five NILs. After 21 days the seedlings were scored for their tolerance to sodicity based on Modified Standard Evaluation System (Gregario et al., 1997) (Table 1). The mean of five replications was considered for the analysis.
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Compatible solute accumulation and stress mitigating effects in barley genotypes contrasting in their salt tolerance

Compatible solute accumulation and stress mitigating effects in barley genotypes contrasting in their salt tolerance

In root tissue, soluble sugars (sucrose, glucose, and fructose) or glycine betaine were below the detection limit (data not shown) of the HPLC. Also, proline accumulation was over 10 times lower than that in leaves. Polyols and amino acids appear to be the major compatible solutes within root tissues (Table 3; Fig. 3, 4). Polyols are mainly synthesized in mature leaves (source tissue) as primary products of photosynthesis and transported to roots (sink tissue) (Noiraud et al., 2001). This is reflected by a root polyol content more than twice that of leaves, regardless of salt treatment (Table 3). Polyols may also act as ROS scavengers, thus protecting enzyme activities and membrane integrity (Smirnoff and Cumbes, 1989; McCue and Hanson, 1990; Bohnert et al., 1995; Shen et al., 1997; Noiraud et al., 2001). The much higher total amino acid content increase in leaves of salt-sensitive varieties (Fig. 4A) may be also indicative of these plants’ greater need for ROS scaveng- ing. A higher Na + accumulation and a more pronounced K + loss in leaves of salt-sensitive genotypes (Fig. 1A, B) results in reduced photosynthetic efficiency (Chen et al., 2005), so generating greater oxidative stress in light- exposed leaves. Thus, more amino acids (especially proline) may be needed to mitigate the ROS stress in salt- sensitive cultivars.
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SALT TOLERANCE STUDIES ON SOME VARIETIES OF WHEAT (TRITICUM SATIVUM) AND BARLEY (HOR- DEUM VULGARE) AT GERMINATION STAGE G. L. MALIWAL

SALT TOLERANCE STUDIES ON SOME VARIETIES OF WHEAT (TRITICUM SATIVUM) AND BARLEY (HOR- DEUM VULGARE) AT GERMINATION STAGE G. L. MALIWAL

It is proposed, therefore, to study the relative salt tolerance as judged by germination percentage of wheat and barley varieties at different levels of salinity [r]

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COMPARATIVE EFFECT OF NACL AND SEAWATER ON GERMINATION OF QUINOA SEED (CHENOPODIUM QUINOA WILLD)

COMPARATIVE EFFECT OF NACL AND SEAWATER ON GERMINATION OF QUINOA SEED (CHENOPODIUM QUINOA WILLD)

Under salt stress, plants have to face two major problems: osmotic effects and ion toxicity (Läuchli and Epstien, 1970). Salt sensitivity or tolerance of plants is related to the stage of growth development (Läuchli and Grattan, 2007). Germination and seedling growth are crucial and at the same time salt-sensitive stages in the development process of most plants. Germination is a critical and a complex phenomenon connecting many physiological and biochemical changes and any stress including salt stress may compromise their process (Wahid et al., 1999). Indeed, seeds subjected to salinity show variations in germination, some fail to germinate, while others tolerate salinity even at high concentrations (Duan et al., 2007).
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Application of salt tolerance indices for screening barley  (hordeum vulgare l ) cultivars

Application of salt tolerance indices for screening barley (hordeum vulgare l ) cultivars

Salinity is a wide-spread problem seriously influencing barley (Hordeum vulgare L.) production, but development of tolerant cultivars is hampered by the lack of effective selection criteria. The objective of this study was to produce screening techniques for selecting salt-tolerant progeny in barley breeding program. Fourteen barley cultivars differing in yield performance were grown in separate experiments under salt stress and non-salt stress conditions in 2008–2009. Eight selection indices including salt susceptibility index (SSI), salt tolerance index (STI), tolerance (TOL), regression coefficient of cultivar yield on environmental index (b), yield index (YI), yield stability index (YSI), mean productivity (MP), and geometric mean productivity (GMP) were calculated based on grain yield under salt and non-salt stress conditions. Results showed that the effectiveness of selection indices in differentiating tolerant cultivars varies with the salt stress intensity. Thus, under moderate salt stress, MP, GMP and STI were more effective in identifying high yielding cultivars in both salt and non-salt stress conditions. Under severe stress, regression coefficient (b) and SSI were found to be more useful in discriminating tolerant cultivars. Breeders should, therefore, take the stress intensity of the environment into account in choosing an index.
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Recent Advances in the Drought Stress Tolerance in Rice Manu Kumar*

Recent Advances in the Drought Stress Tolerance in Rice Manu Kumar*

Many studies were done in the development of drought stress-tolerant transgenic plants, including crop plants. Rice is considered to be a vital crop target for improving drought stress tolerance. Much transgenic rice showed improved drought stress tolerance was reported to date. They are genetically engineered plants that are developed by using genes that encode proteins involved in drought stress regulatory networks. These proteins include protein kinases, transcription factors, enzymes related to osmoprotectant or plant hormone synthesis, receptor- like kinase. Of the drought stress-tolerant transgenic rice plants described in this review, most of them display retarded plant growth. In crop crops, plant health is a fundamental agronomic trait that can directly affect yield. By understanding the regulatory mechanisms of retarded plant growth under drought stress, conditions are necessary precursors to developing genetically modified plants that result in high yields.
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Tolerance of four spring barley (Hordeum vulgare L ) varieties to weed harrowing

Tolerance of four spring barley (Hordeum vulgare L ) varieties to weed harrowing

The change in vegetation cover (DVC) caused by post- emergence weed harrowing was analysed by Eqn (7) for differences between the varieties in the herbicide-treated plots. There was a very strong effect of variety (P < 0.0001) and year (P < 0.0001). We found sig- nificant effects of the interaction between nutrient level and year (P = 0.039). Orthega was covered less by harrowing than other varieties. We found only a 7% reduction in this variety compared with Otira, where the reduction was more than the double (15%). In herbi- cide-untreated plots, DVC represents the reduction in the sum of vegetation cover of both weeds and crop. There were only slight differences in the levels of DVC, whether weeds were present or not, indicating that the main differences in DVC were caused by differences in crop cover (Table 3). We found a significant negative corr- elation between DVC and canopy height measured 6 days after weed harrowing in 2004 (low nutrient level, P < 0.001; high nutrient level, P = 0.007). In 2005, there was no significant correlation (Fig. 3).
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Drought Tolerance in Some of Red Rice Line Based on Morphology at Vegetative Stage

Drought Tolerance in Some of Red Rice Line Based on Morphology at Vegetative Stage

During healing for 10 days some lines were seen in normal conditions for less than 10 days. Based on the assessment until the 10th day, the lines KF42-2-3, KF42- 4-2, KF42-7-3, KF42-10-2 and KF42-13-2 require 9 days to return to normal conditions, while other lines returned to normal on the 10th day of testing. This means that, all lines can return to normal leaf conditions on the 10th day. However, recovery observation cannot be used as an indicator in determining the tolerance level of the line tested. This is because within 10 days the plant has returned to normal before the 10th day, so that the damage level can be observed for more than 10 days. Based on observations of the level of recovery, showed that the lines tested had a constant response which was very tolerant to drought stress which was able to return to normal conditions within 10 days. This indicates that these lines have the ability to maintain growth in dense conditions (drought). Arrandeau (1989) states that the drought recovery mechanism is related to the ability of plants to restore growth after a certain period of drought. Arrandeau (1989) states that the drought recovery mechanism is related to the ability of plants to restore growth after a certain period of drought. Fukai and Cooper (1995) added that this mechanism is important when drought occurs at the beginning of plant growth and development, this shows in several genotypes that are able to produce more tillers and produce grain after a period of drought. The ability of plants to improve the metabolic system due to dryness is related to its ability to keep the leaves green during periods of drought. Maintaining the leaves remain green when drought stress occurs during panicle initiation is very important because leaves that remain green provide assimilation for the development of panicles so that the production of spikelet will increase (Tubur, 2011).
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SEEDLING SIZE AND VARIETAL CHARACTERISTICS AS THE TOOLS FOR AVOIDANCE TO SUBMERGENCE STRESS AT SEEDLING STAGE IN RICE

SEEDLING SIZE AND VARIETAL CHARACTERISTICS AS THE TOOLS FOR AVOIDANCE TO SUBMERGENCE STRESS AT SEEDLING STAGE IN RICE

In south and south east Asia, rainfed lowland rice is generally affected by submergence during flash floods. The frequency and duration of floods differ from place to place, year to year causing different degrees of plant mortality. In Assam, the occurrence of flash floods is widespread in wet season in relatively low lying areas where localized excess rainfall and water supplied by nearby rivers interact with impaired natural drainage. This situation leads to complete submergence of the rice seedlings and the situation may even continue for 10-20 days duration. This causes impairement in their physiological processes like photosynthesis, root anaerobiosis, mobilization of stored carbohydrates etc. and kills the seedlings completely. Therefore, such situation warrants for either need of rice varieties having inherent morpho-physiological makeup to tolerate complete submergence stress more so at seedling stage or needs some management practices for avoidance of the submergence stress.
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Generational Mean Analysis of Salt Tolerance during Osmotic Phase in Maize Seedling

Generational Mean Analysis of Salt Tolerance during Osmotic Phase in Maize Seedling

The analysis of the variables for hydric relations (LWL and RWC) showed different behavior. The LWL trait displayed significant differences in both crosses, whereas RWC did not. This could be attributed to the fact that LWL is associated with the loss of water through the epidermis of the leaf determined by the thickness of the cuticle (secondary transpiration). Given that this characte- ristic is of a constitutive nature, it is expected not to vary under saline stress. RWC, on the other hand, is associated with the diminishment of the Ψo of the tissues and is subject to modifications throughout the crop cycle according to the Ψo in the soil. In our experiment, ten days of salinization were insufficient to display significant differences.
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Barley seed sensitivity to water stress at germination stage

Barley seed sensitivity to water stress at germination stage

stration of seed with greater water sensitivity is the elon- gation of emergence time. Less observation was yet ded- icated to air substance, oxygen, respectively during germination. Oxygen deficit can demonstrate inhibition of root growth (Bewley and Black 1994). According to Crawford (cit. Halmer and Bewley 1984), the tolerant spe- cies react to anaerobic conditions during anoxia by de- creasing the anaerobic respiration and lactate and ethanol production for the oxygen deficit balance. Intol- erant species conversely mark out a great anaerobic res- piration and a high level of ethanol. Perry and Ellerton (1983) observed this phenomenon in barley caryopsis with a lower vigour. While oxygen is necessary for respi- ration of imbibed seeds, CO 2 and ethylene, which are
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Gene Expression Patterns of some Transcription Factors (Zpt2-1, CBF4, bHLH) under Salt Stress in Alfalfa by Using qPCR

Gene Expression Patterns of some Transcription Factors (Zpt2-1, CBF4, bHLH) under Salt Stress in Alfalfa by Using qPCR

(Medicago truncatula) has attracted the interest of re- searchers as a very desirable model plant for genetic stu- dies due to its small and diploid genome, self-fertilization, and short life cycle [13]. These characters have made an- nual alfalfa a suitable plant for identifying genes involved intolerance against abiotic stresses and breeding for these genes [13]. The large number of molecular studies con- ducted on this plant has yielded a huge volume of data related to genome sequencing and gene expression analy- sis that is stored in databases [14]. Li et al., [15] have indi- cated that CBF4 and MYB112 play key role in tolerance to abiotic stresses in Medicago species. Also, Merchan et al., [16] showed the TFIIIA-like TF, Zpt2-2, is involved in recovery responses to salinity and cold stress in M. trunca- tula. De Lorenzo et al., [17] reported that, overexpression of MtZpt2-1 or MtZpt2-2 in the sensitive genotype of M. truncatula led to significantly increase in root growth un- der salt stress, as well have a major role in adaptive res- ponses. Despite the large amount of information on the effects that salinity has on transcriptome pattern of M. truncatula, there are few studies regarding the mentioned area on the Iranian alfalfa cultivars. Therefore, this re- search was carried out using Real-Time PCR to study ex- pression patterns of genes related to the transcription fac- tors Zpt2-1, CBF4, and bHLH under salt stress in alfalfa.
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Mapping QTLs for Cold Tolerance at Seedling Stage Using an Oryza sativa O. rufipogon Backcross Inbred Line Population

Mapping QTLs for Cold Tolerance at Seedling Stage Using an Oryza sativa O. rufipogon Backcross Inbred Line Population

a F 2 population from 9311/DWR (Zuo et al. 2010). Using root conductivity, leaf osmotic potential and plant survival rate as cold-tolerant trait indices, Xia et al. (2010) and Xiao et al. (2014, 2015) detected two QTLs qRC10-1 and qRC10-2 for root conduc- tivity correlated with cold tolerance, and two QTLs qLOP2 and qPSR2-1 for leaf osmotic potential and plant survival related with cold-tolerance (Xia et al. 2010; Xiao et al. 2014, 2015). In the present study, a BIL population, where the donor parent is DWR, was used to identify the QTLs controlling cold tolerance at seedling stage. QTL of qSCT4.3 for cold tolerance identified on chromosome 4 and explaining 8.83% of phenotypic variation was detected in a BC 1 F 1 population by Chen et al. (2002) as well. Four major QTLs detected on chromosome 8 and 12 are new loci involving cold tolerance at seedling stage compared with the previous study of Chen et al. (2002). The QTLs or genes identified from DWR will promote improving rice cold tolerance and will contribute to the understanding of its molecular mechanisms.
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Comparison of Salt Tolerance in Brassicas and Some Related Species

Comparison of Salt Tolerance in Brassicas and Some Related Species

In previous studies, the Brassicas were usually grown in salt conditions to compare parameters such as relative germination rate, root length, fresh seedling weight or seed yield [10-17]. In the present study the seeds of Bras- sicas and related species were grown on sand cultures with and without salt to explore an efficient index to com- pare the salt tolerance in Brassicas and related species and to determine variations in degree of salt tolerance at inter- and intra-specific levels particularly at the germi- nation and seedling stages.
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