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Mark Tester - One of the best experts on this subject based on the ideXlab platform.
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Assessing Rice Salinity Tolerance: From Phenomics to Association Mapping.
Methods in molecular biology (Clifton N.J.), 2021Co-Authors: Nadia Al-tamimi, Mark Tester, Helena Oakey, Sónia NegrãoAbstract:Rice is the most salt-sensitive cereal, suffering yield losses above 50% with soil Salinity of 6 dS/m. Thus, understanding the mechanisms of rice Salinity Tolerance is key to address food security. In this chapter, we provide guidelines to assess rice Salinity Tolerance using a high-throughput phenotyping platform (HTP) with digital imaging at seedling/early tillering stage and suggest improved analysis methods using stress indices. The protocols described here also include computer scripts for users to improve their experimental design, run genome-wide association studies (GWAS), perform multi-testing corrections, and obtain the Manhattan plots, enabling the identification of loci associated with Salinity Tolerance. Notably, the computer scripts provided here can be used for any stress or GWAS experiment and independently of HTP.
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Quantile function modeling with application to Salinity Tolerance analysis of plant data
BMC plant biology, 2019Co-Authors: Gaurav Agarwal, Mark Tester, Stephanie Saade, Mohammad Shahid, Ying SunAbstract:In plant science, the study of Salinity Tolerance is crucial to improving plant growth and productivity under saline conditions. Since quantile regression is a more robust, comprehensive and flexible method of statistical analysis than the commonly used mean regression methods, we applied a set of quantile analysis methods to barley field data. We use univariate and bivariate quantile analysis methods to study the effect of plant traits on yield and Salinity Tolerance at different quantiles. We evaluate the performance of barley accessions under fresh and saline water using quantile regression with covariates such as flowering time, ear number per plant, and grain number per ear. We identify the traits affecting the accessions with high yields, such as late flowering time has a negative impact on yield. Salinity Tolerance indices evaluate plant performance under saline conditions relative to control conditions, so we identify the traits affecting the accessions with high values of indices using quantile regression. It was observed that an increase in ear number per plant and grain number per ear in saline conditions increases the Salinity Tolerance of plants. In the case of grain number per ear, the rate of increase being higher for plants with high yield than plants with average yield. Bivariate quantile analysis methods were used to link the Salinity Tolerance index with plant traits, and it was observed that the index remains stable for earlier flowering times but declines as the flowering time decreases. This analysis has revealed new dimensions of plant responses to Salinity that could be relevant to Salinity Tolerance. Use of univariate quantile analyses for quantifying yield under both conditions facilitates the identification of traits affecting Salinity Tolerance and is more informative than mean regression. The bivariate quantile analyses allow linking plant traits to Salinity Tolerance index directly by predicting the joint distribution of yield and it also allows a nonlinear relationship between the yield and plant traits.
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Growth curve registration for evaluating Salinity Tolerance in barley.
Plant methods, 2017Co-Authors: Rui Meng, Mark Tester, Stephanie Saade, Sebastian Kurtek, Bettina Berger, Chris Brien, Klaus Pillen, Ying SunAbstract:Smarthouses capable of non-destructive, high-throughput plant phenotyping collect large amounts of data that can be used to understand plant growth and productivity in extreme environments. The challenge is to apply the statistical tool that best analyzes the data to study plant traits, such as Salinity Tolerance, or plant-growth-related traits. We derive family-wise Salinity sensitivity (FSS) growth curves and use registration techniques to summarize growth patterns of HEB-25 barley families and the commercial variety, Navigator. We account for the spatial variation in smarthouse microclimates and in temporal variation across phenotyping runs using a functional ANOVA model to derive corrected FSS curves. From FSS, we derive corrected values for family-wise Salinity Tolerance, which are strongly negatively correlated with Na but not significantly with K, indicating that Na content is an important factor affecting Salinity Tolerance in these families, at least for plants of this age and grown in these conditions. Our family-wise methodology is suitable for analyzing the growth curves of a large number of plants from multiple families. The corrected curves accurately account for the spatial and temporal variations among plants that are inherent to high-throughput experiments.
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Quantifying the three main components of Salinity Tolerance in cereals
Plant Cell and Environment, 2009Co-Authors: Karthika Rajendran, Mark Tester, Stuart J. RoyAbstract:Salinity stress is a major factor inhibiting cereal yield throughout the world. Tolerance to Salinity stress can be considered to contain three main components: Na(+) exclusion, Tolerance to Na(+) in the tissues and osmotic Tolerance. To date, most experimental work on Salinity Tolerance in cereals has focused on Na(+) exclusion due in part to its ease of measurement. It has become apparent, however, that Na(+) exclusion is not the sole mechanism for Salinity Tolerance in cereals, and research needs to expand to study osmotic Tolerance and tissue Tolerance. Here, we develop assays for high throughput quantification of Na(+) exclusion, Na(+) tissue Tolerance and osmotic Tolerance in 12 Triticum monococcum accessions, mainly using commercially available image capture and analysis equipment. We show that different lines use different combinations of the three Tolerance mechanisms to increase their total Salinity Tolerance, with a positive correlation observed between a plant's total Salinity Tolerance and the sum of its proficiency in Na(+) exclusion, osmotic Tolerance and tissue Tolerance. The assays developed in this study can be easily adapted for other cereals and used in high throughput, forward genetic experiments to elucidate the molecular basis of these components of Salinity Tolerance.
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Salinity Tolerance and sodium exclusion in genus Triticum
Breeding Science, 2009Co-Authors: Yuri Shavrukov, Peter Langridge, Mark TesterAbstract:The ability of plants to exclude sodium from the shoot is one of the major components of Salinity Tolerance. In this study, considerable variability in sodium exclusion within different species is demonstrated. The diploid species T. monococcum revealed a large (50-fold) variability in sodium exclusion in contrast to T. urartu, which was significantly less variable (10-fold). These species with the A genome are known to be salt sensitive, whilst T. (Aegilops) tauschii, a diploid species with the D genome, was very salt tolerant, but had only moderate variability in sodium exclusion (10-fold). The tetraploid species T. turgidum ssp. durum (both cultivated and landraces) and wild emmer T. dicoccoides (all with the AB genome) showed a range of variability in both Salinity Tolerance and sodium exclusion. The general pattern (from most sensitive and with highest Na+ accumulation) was as follows: durum (cultivated) < durum (landraces) < wild emmer. Cultivated durum wheats had minimal or no variability, whereas landraces of durum wheats had greater variability, two excellent genotypes having been identified which combine very low sodium accumulation with very high Salinity Tolerance. Wild emmer was extremely variable. Hexaploid bread wheat, T. aestivum with the ABD genome, is known to be more salt tolerant, having an effective mechanism for sodium exclusion but only low variability.
Kenneth B Marcum - One of the best experts on this subject based on the ideXlab platform.
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Relative Salinity Tolerance of 35 Lolium spp. Cultivars for Urban Landscape and Forage Use
Developments in Soil Salinity Assessment and Reclamation, 2012Co-Authors: Kenneth B Marcum, Mohammad PessarakliAbstract:Increasing population growth, particularly in urban centers, is resulting in critical freshwater shortages for both agriculture and urban use worldwide. To counteract existing water crises, many governments are restricting use of freshwater sources for irrigation. In the urban setting, governments are requiring use of reclaimed wastewater or other secondary saline water sources in lieu of freshwater for landscape irrigation. Lolium spp. (ryegrasses) is widely used for forage as well as in urban turf landscapes. Relative Salinity Tolerance of 35 Lolium spp. cultivars was determined in solution culture by measuring changes in shoot weight, root weight, rooting depth, and % green leaf canopy area, relative to control (non-salinized) plants. There was a wide range in Salinity Tolerance of the tested cultivars, ranging from salt tolerant (e.g., cv. Paragon) to salt sensitive (e.g., cv. Midway). All shoot parameters were highly correlated, being mutually effective predictors of Salinity Tolerance. Root dry weight, significantly correlated with all shoot quality and growth parameters, was also effective in predicting relative Salinity Tolerance. However, rooting depth was not correlated with other parameters, and therefore not effective in predicting relative Salinity Tolerance. Based on these results, it is concluded that salt-tolerant cultivars exist within Lolium spp. for agricultural forage and urban landscape use.
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Salinity Tolerance of Ryegrass Turf Cultivars
HortScience, 2010Co-Authors: Kenneth B Marcum, Mohammad PessarakliAbstract:Relative Salinity Tolerance of 32 perennial (Lolium perenne L.) and three intermediate (Lolium ·hybridum Hausskn.) ryegrass turf cultivars was determined by measuring turf leaf clipping dry weight, root weight, rooting depth, and percent green leaf canopy area relative to control (non-salinized) plants. After gradual acclimation, grasses were exposed to moderate Salinity stress (6 dSm -1 ) for 6 weeks through solution culture in a controlled environment greenhouse. Shoot parameters were highly cor- related, being mutually effective predictors of Salinity Tolerance. After 6 weeks of Salinity stress, percent green leaf canopy area (GL) was correlated with relative (to control) final week leaf clipping weight (LWREL )( r = 0.90) and with linear slope of decline of weekly leaf clipping weight over the 6-week exposure to Salinity (LWSLOPE )( r = 0.66). Rooting parameters root dry weight (RW) and rooting depth (RD), although significantly correlated with all shoot parameters, were only moderately effective in predicting relative Salinity Tolerance. 'Paragon' was the most salt-tolerant as indicated by all parameters. Other salt-tolerant cultivars included Divine and Williamsburg. Interme- diate ryegrass cultivars (Froghair, Midway, and Transist) were invariably found within the most salt-sensitive category for all parameters.
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genotypic variation in Salinity Tolerance of distichlis spicata turf ecotypes
Australian Journal of Experimental Agriculture, 2007Co-Authors: Kenneth B Marcum, Nicholas P Yensen, John E LeakeAbstract:Water quantity and quality issues are accelerating the search for alternative xeriphytic and halophytic turf species. Growth and physiological responses to Salinity of eight Distichlis spicata (L.) Greene genotypes were observed to elucidate Salinity Tolerance mechanisms operating in the species. Accession 1043 was superior in Salinity Tolerance to other genotypes, as indicated by percentage canopy green leaf area, relative (to control) shoot growth, relative root growth, and rooting depth, when exposed to increasing Salinity up to 1.0 mol/L NaCl. Salinity Tolerance was associated with complete, though minimal, shoot osmotic adjustment, maintenance of low shoot saline ion levels, and high shoot K+/Na+ ratios, all of which were facilitated by high leaf salt gland ion excretion rates.
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Salinity Tolerance and salt gland excretion efficiency of bermudagrass turf cultivars
Crop Science, 2006Co-Authors: Kenneth B Marcum, Mohammad PessarakliAbstract:Need for salt tolerant turfgrasses is increasing due to government mandates requiring use of low quality, secondary water sources for turfgrass irrigation. Objectives of this study were to determine the range in Salinity Tolerance among modern Cynodon spp. (bermudagrass) turf cultivars, determine if leaf salt gland excretion is an important Salinity Tolerance mechanism in bermudagrass, and if Salinity Tolerance is associated with the rate, or efficiency of leaf salt gland excretion. Salinity responses of thirty five bermudagrass turf cultivars [Cynodon dactylon (L.) Pers, and C. dactylon X Cynodon transvaalensis (Burtt-Davey)] were determined by exposing plants to five Salinity levels (0, 15, 30, 45, and 60 dS m -1 ). Salinity Tolerance among cultivars was determined by shoot dry weight reduction relative to control plants and by percent green leaf canopy area (GLCA). Salinity resulting in 50% reduction in shoot dry weight (SW50) ranged from 26 to 40 dS m -1 , indicating a wide range in Salinity Tolerance within this genus. Salt glands were present on both abaxial and adaxial leaf surfaces of all cultivars. Salinity Tolerance was negatively correlated with leaf tissue Na + concentration and positively correlated with leaf salt gland Na + excretion rate, indicating that Salinity Tolerance in bermudagrasses is associated with shoot saline ion exclusion and to leaf salt gland excretion efficiency.
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relative Salinity Tolerance of 21 turf type desert saltgrasses compared to bermudagrass
Hortscience, 2005Co-Authors: Kenneth B Marcum, Mohammad Pessarakli, D. M. KopecAbstract:Relative Salinity Tolerance of 21 desert saltgrass accessions (Distichlis spicata [L.] Greene var. stricta (Torr.) Beetle), and one hybrid bermudagrass 'Midiron' (Cynodon dactylon [L.] Pers. var. dactylon × C. transvaalensis Burtt-Davy 'Midiron') were determined via solution culture in a controlled-environment greenhouse. Salinity in treatment tanks was gradually raised, and grasses progressively exposed to 0.2, 0.4, 0.6, 0.8, and 1.0 M total Salinity in sequence. Grasses were held at each Salinity level for 1 week, followed by determination of relative Salinity injury. Relative (to control) live green shoot weight (SW), relative root weight (RW), and % canopy green leaf area (GLA) were highly correlated with one-another (all r values >0.7), being mutually effective indicators of relative Salinity Tolerance. The range of Salinity Tolerance among desert saltgrass accessions was substantial, though all were more tolerant than bermudagrass. Accessions A77, A48, and ASS suffered little visual shoot injury, and continued shoot and root growth at a low level, when exposed up to 1.0 M (71,625 mg.L -1 ); sea water is about 35,000 mg-L-'), and therefore can be considered halophytes.
Prasanta K. Subudhi - One of the best experts on this subject based on the ideXlab platform.
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Identification and validation of QTLs for seedling Salinity Tolerance in introgression lines of a salt tolerant rice landrace ‘Pokkali’
2017Co-Authors: Teresa B. De Leon, Steven Linscombe, Prasanta K. SubudhiAbstract:Salinity is a major threat to rice production worldwide. Several studies have been conducted to elucidate the molecular basis of Salinity Tolerance in rice. However, the genetic information such as quantitative trait loci (QTLs) and molecular markers, emanating from these studies, were rarely exploited for marker-assisted breeding. To better understand Salinity Tolerance and to validate previously reported QTLs at seedling stage, a set of introgression lines (ILs) of a salt tolerant donor line ‘Pokkali’ developed in a susceptible high yielding rice cultivar ‘Bengal’ background was evaluated for several morphological and physiological traits under salt stress. Both SSR and genotyping-by-sequencing (GBS) derived SNP markers were utilized to characterize the ILs and identify QTLs for traits related to Salinity Tolerance. A total of eighteen and thirty-two QTLs were detected using SSR and SNP markers, respectively. At least fourteen QTLs detected in the RIL population developed from the same cross were validated in IL population. Analysis of phenotypic responses, genomic composition, and QTLs present in the tolerant ILs suggested that the mechanisms of Tolerance could be Na+ dilution in leaves, vacuolar Na+ compartmentation, and possibly synthesis of compatible solutes. Our results emphasize the use of salt injury score (SIS) QTLs in marker-assisted breeding to improve Salinity Tolerance. The tolerant lines identified in this study will serve as improved breeding materials for transferring Salinity Tolerance without the undesirable traits of Pokkali. Additionally, the lines will be useful for fine mapping and map-based cloning of genes responsible for Salinity Tolerance.
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Genetic variation in Southern USA rice genotypes for seedling Salinity Tolerance
Frontiers in plant science, 2015Co-Authors: Teresa B. De Leon, Glenn B. Gregorio, Steven D. Linscombe, Prasanta K. SubudhiAbstract:The success of a rice breeding program in developing salt tolerant varieties depends on genetic variation and the salt stress response of adapted and donor rice germplasm. In this study, we used a combination of morphological and physiological traits in multivariate analyses to elucidate the phenotypic and genetic variation in Salinity Tolerance of thirty Southern USA rice genotypes, along with nineteen donor genotypes with varying degrees of Tolerance. Significant genotypic variation and correlations were found among the salt injury score (SIS), ion leakage, chlorophyll reduction, shoot length reduction, shoot K+ concentration, and shoot Na+/K+ ratio. Using these parameters, the combined methods of cluster analysis and discriminant analysis validated the Salinity response of known genotypes and classified most of the USA varieties into sensitive groups, except for three and seven varieties placed in the tolerant and moderately tolerant groups, respectively. Discriminant function and MANOVA delineated the differences in Tolerance and suggested no differences between sensitive and highly sensitive groups. DNA profiling using simple sequence repeat markers showed narrow genetic diversity among USA genotypes. However, the overall genetic clustering was mostly due to subspecies and grain type differentiation and not by varietal grouping based on Salinity Tolerance. Among the donor genotypes, Nona Bokra, Pokkali, and its derived breeding lines remained the donors of choice for improving Salinity Tolerance during the seedling stage. However, due to undesirable agronomic attributes and photosensitivity of these donors, alternative genotypes such as TCCP266, Geumgangbyeo, and R609 are recommended as useful and novel sources of Salinity Tolerance for USA rice breeding programs.
Alireza Zebarjadi - One of the best experts on this subject based on the ideXlab platform.
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Haplotype analysis of QTLs attributed to Salinity Tolerance in wheat (Triticum aestivum).
Molecular biology reports, 2013Co-Authors: Somaye Sardouie-nasab, Ghasem Mohammadi-nejad, Alireza ZebarjadiAbstract:A diverse collection of wheat germplasm, consisting of 100 bread wheat lines with varying levels of Salinity Tolerance were evaluated based on incomplete block design (lattice) with two replications in field conditions. Plant material was screened for Salinity Tolerance under normal and saline field conditions. Subsequently in order to assess the haplotype diversity of QTLs attributed to Salinity Tolerance in wheat (Triticum aestivum), a collection of 30 extremes tolerant and sensitive genotypes among them were selected for genotyping on the basis of morphological, physiological and phenological traits. Genotyping was done using microsatellite markers which had been detected as the flanking regions of large effect QTLs attributed to Salinity Tolerance on chromosomes 2A, 4D and 3B. Combined analysis of saline and normal conditions revealed that genotypes showed highly significant responses. Association analysis of SSR markers with traits, showed markers Xcfa2121b, Xgwm10 and Xgwm296 on chromosome 2A and markers Xgwm194 and xgwm624 for chromosome 4D, had significant association with most of measured traits. Haplotype diversity analysis showed markers Xgwm10, Xgwm445, Xbarc353.2, Xgwm312, Xgwm515 and Xwmc296 on chromosome 2A as well as markers Xwmc326 and Xgwm345, Xbarc48.4 on chromosomes 3B and 4D were identified as the best markers attributed to Salinity Tolerance and they can be informative markers for improvement of Salinity Tolerance through marker-assisted selection programs.
Abelardo C. Vegetti - One of the best experts on this subject based on the ideXlab platform.
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Salt Glands in the Poaceae Family and Their Relationship to Salinity Tolerance
The Botanical Review, 2015Co-Authors: Gabriel Céccoli, Julio Ramos, Vanesa Pilatti, Ignacio Dellaferrera, Juan C. Tivano, Edith Taleisnik, Abelardo C. VegettiAbstract:The Poaceae is one of the most important Angiosperm families, in terms of morphological diversity, ecology and economic importance. Species within this family show a very wide variation in terms of Salinity Tolerance. Salt secretion through salt glands plays a significant role in regulating ion balance, contributing to Salinity Tolerance. This review focuses on salt glands in the Poaceae family and their role in the Salinity Tolerance. In Poaceae microhairs have been observed in all subfamilies, except Pooideae, but functioning salt glands are reported only in genera belonging to the Chloridoideae subfamily. Structural, ultrastructural and physiological features of salt glands are summarized and discussed and the use of salt glands as potential target features for improving salt Tolerance of crops is considered.
