Evaluation Of Drought Tolerance Research Articles

Physiological evaluation of drought tolerance in Poplar (Populus deltoids L.) for different drought levels

Experiments were conducted to evaluate drought tolerance under different levels of water stress in poplar trees. The cuttings of Populus deltoides L. (clone Kranti) were exposed to four different watering regimes (100, 75, 50 and 25% of the field capacity) and changes in physiological parameters related with drought tolerance were recorded. Drought treatments (75%, 50% and 25% FC) decreased net photosynthetic rate (Pn), transpiration rate (E), chlorophyll fluorescence (Fv/Fmax), plant height, number of leaves, specific leaf area (SLA), leaf area index (LAI) and total biomass content in all the three watering regimes compared to control (100% FC). Cuttings were showed poor performance with increasing levels of drought stress. Severity were observed in Pn, E, Fv/Fmax, plant height, stem diameter, leaf area and number of leaves, SLA, LAI and total biomass content with increasing levels of water stress. Decreased CO2 assimilation and transpiration rate due to instantaneous closure of stomata to protect the plants against hazardous effects of water stress leads to overall decrease in biomass of cuttings with 60 days water stress treatments. By visualizing the results, we can say that Scarcity of water is a severe environmental constraint to plant productivity. Drought-induced loss in plant productivity, since both the severity and duration of the stress are critical. Secondly, we can emphasise with our experiment that poplar plants can maintain their better growth and biomass only up to 75-50% of FC after that stress shows its severity so much that the aim of plants is only to survive and biomass maintenance become vague.

Evaluation of Drought Tolerance and Tolerance-associated Traits in Barley Genotypes

Evaluation of Drought Tolerance and Tolerance-associated Traits in Barley Genotypes

Evaluation of drought tolerance of spring wheat lines in the Forest-Steppe of Ukraine

The aim and tasks of the study envisaged assessing and identifying spring wheat lines of competitive variety trial by drought tolerance to be involved in research programs as starting material. Material and methods. The study was conducted at the Laboratory of Spring Wheat Breeding of VM Remeslo Myronivka Institute of Wheat of NAAS of Ukraine in 2013-2014. Fifty five spring wheat lines of competitive variety trial were studied. Drought tolerance was evaluated in the field by the spike realization coefficient and in the laboratory by the seed germination percentage in sucrose solution as well as by electrolyte leakage. Results and discussion. The meteorological conditions during the study period were contrast, which allowed evaluating and selecting breeding material by drought tolerance. Bread wheat lines of competitive variety trial Lutescens 10-36, Lutescens 11-24, Lutescens 12-30, Erythrospermum 13-11, Albidum 10-41, and others and durum wheat lines Leukurum 13-02, Melianopus 10-03, Leukurum 12-09, Leukurum 12-16, and Leukurum 12-41 were selected by the spike realization coefficient. Lines Melianopus 10-03, Leukurum 10-26, Lutescens 05-24, Lutescens 10-36, Lutescens 11-02, and Lutescens 12-26, and others were selected the seed germination percentage in sucrose solution. Lines Lutescens 10-36, Lutescens 05-24, Lutescens 10-23, Albidum 10-41, Melianopus 10-02, Leukurum 10-26, and others were selected by electrolyte leakage; their indices were much higher than those in standards. Conclusions. Thus, in 2013-2014, the three methods of evaluation of drought tolerance selected spring lines that were the most drought tolerant: Lutescens 10-36 (submitted to the state variety trial as variety ‘Oksamyt Myronivskyi’), Melianopus 10-02 (submitted to the state variety trial as variety ‘MIP Raiduzhna’), Albidum 10-41, Leukurum 10-14, which are recommended as starting material in breeding for drought tolerance

ABA Sensitivity as a Criterion for Drought Tolerance in Wheat (Triticum aestivum L.) Cultivars

Abstract Criteria used for evaluating drought tolerance of wheat cultivars demanding more time and efforts are usually not efficient and conclusive. Present study was conducted to evaluate ABA sensitivity as a criterion for evaluating drought tolerance of wheat cultivars at an early stage. Ten cultivars of wheat were subjected to drought at 3-leaf stage to select the most sensitive and two tolerant cultivars using mortality rate. Tatara was found the most susceptible whereas GA-2002 and Chakwal-50 were the cultivars with maximum drought tolerance. These cultivars were used to study sensitivity to applied absicic acid (based on germination index and relative growth inhibition rate) and physiological responses (leaf water content, chlorophyll stability index, coefficient of relative inhibition and proline accumulation) under drought stress. Highest ABA-sensitivity was recorded in GA-2002 and Chakwal-50 whereas Tatara manifested minimum sensitivity. ABA-sensitivity corresponded to physiological indices of drought tolerance. Results show that ABA-sensitivity is an efficient criterion that can be used to evaluate drought tolerance of wheat cultivars at early stage.

Molecular Analysis of Drought Tolerance in Guava Based on In Vitro PEG Evaluation

Forty landraces of guava were subjected to drought tolerance evaluation based on in vitro polyethylene glycol (PEG) treatment. Nodal stem segments with lateral buds were used as explant. Five concentrations (i.e. 0, 4, 6, 8 and 10 %) of PEG were tested, among which the optimum concentration for screening was determined as 8 %. Analysis of variance showed highly significant variation among the tested landraces, concentrations of PEG and the interaction between them in the percentage of response (%R), number of shoot per explant (NSE) and drought susceptibility index. The average percentage of reduction due to PEG treatment was 48.30 and 52.57 % for the %R and NSE, respectively. Heritability and genetic advance were increased due to drought stress for %R, while they were decreased for NSE, indicating that %R was more related to drought stress than NSE. The molecular analysis of the highest and lowest responsive landraces was performed using sequence related amplified polymorphism (SRAP) and inter-simple sequence repeats (ISSR). Both markers were effective in discriminating the tested landraces and completely separated them into two clusters related to %R under PEG. ISSR showed a higher percentage of polymorphism, polymorphic information content and diversity index compared with SRAP. However, SRAP was more effective than ISSR in showing a higher primer resolving power and a number of unique specific bands for drought tolerance and susceptibility. Drought in vitro evaluation method established here is effective, inexpensive and manageable in genotype screening for drought tolerance in guava and could be used in other woody plant species.

Phenotyping Peanut Genotypes for Drought Tolerance

ABSTRACTDrought and heat stress can result in aflatoxin contamination of peanuts especially when this occurs during the last three to six wk of the growing season. Identifying drought-tolerant genotypes may aid in development of peanuts that are less susceptible to aflatoxin contamination. Research was conducted to phenotype seven peanut genotypes based on their response to drought stress. Six peanut genotypes that have exhibited lower aflatoxin and/or drought tolerance in previous researches (Tifguard, Tifrunner, Florida-07, PI 158839, NC 3033, C76-16) were compared to an aflatoxin-susceptible genotype, A72. The phenotyping methods included visual ratings, chlorophyll fluorescence (PIABS, ϕEO, and Fv/Fm), SPAD chlorophyll meter reading (SCMR), normalized difference vegetation index (NDVI), canopy temperature (CT), canopy temperature depression (CTD), and pod yield. Based on these traits, Tifguard and Tifrunner exhibited greater drought tolerance mechanisms than the other genotypes and may be good candidates to be incorporated in future drought tolerance studies. After the aflatoxin content of the different genotypes was measured, aflatoxin contamination showed high correlations with visual ratings (0.85), CTD (0.81), NDVI (0.79), and CT (0.73), and moderate correlations with Fv/Fm (0.62) and SCMR (0.57) (P ≥ 0.05). These easily measurable, rapid and cost-effective phenotyping methods may be used as alternative to more tedious and costly methods of identifying genotypes that are less susceptible to aflatoxin contamination. Using a combination of these methods is beneficial but not always practical. The combined use of visual ratings, CTD and NDVI is advised for initial evaluation of drought tolerance in peanut genotypes.

Phenotyping Peanut Genotypes for Drought Tolerance

Drought and heat stress can result in aflatoxin contamination of peanuts especially when this occurs during the last three to six wk of the growing season. Identifying drought-tolerant genotypes may aid in development of peanuts that are less susceptible to aflatoxin contamination. Research was conducted to phenotype seven peanut genotypes based on their response to drought stress. Six peanut genotypes that have exhibited lower aflatoxin and/or drought tolerance in previous researches (Tifguard, Tifrunner, Florida-07, PI 158839, NC 3033, C76-16) were compared to an aflatoxin-susceptible genotype, A72. The phenotyping methods included visual ratings, chlorophyll fluorescence (PI_ABS, φ_EO, and F_v/F_m), SPAD chlorophyll meter reading (SCMR), normalized difference vegetation index (NDVI), canopy temperature (CT), canopy temperature depression (CTD), and pod yield. Based on these traits, Tifguard and Tifrunner exhibited greater drought tolerance mechanisms than the other genotypes and may be good candidates to be incorporated in future drought tolerance studies. After the aflatoxin content of the different genotypes was measured, aflatoxin contamination showed high correlations with visual ratings (0.85), CTD (0.81), NDVI (0.79), and CT (0.73), and moderate correlations with F_v/F_m (0.62) and SCMR (0.57) (P ≥ 0.05). These easily measurable, rapid and cost-effective phenotyping methods may be used as alternative to more tedious and costly methods of identifying genotypes that are less susceptible to aflatoxin contamination. Using a combination of these methods is beneficial but not always practical. The combined use of visual ratings, CTD and NDVI is advised for initial evaluation of drought tolerance in peanut genotypes.

Evaluation of drought tolerance in backcross inbred lines of rice genotypes based on selection indices

Drought tolerant lines of Improved White Ponni (IWP) were developed by marker assisted back crossing of IWP with Apo. Three drought tolerant backcross inbred lines (BILs), developed by introgressing the drought tolerance QTLs from Apo were evaluated for drought tolerance along with their parents based on drought indices. Twenty drought indices were calculated based on grain yield under drought and irrigated conditions. Yield in drought and irrigated conditions were significantly and positively correlated with mean productivity index, harmonic mean, geometric mean of productivity and stress tolerance index. Ranking method and three dimensional plot discriminated IWP-4-2 as the most drought tolerant genotype, which was placed in group A (Genotypes, which performed good under drought and irrigated conditions), and outperformed the drought tolerant parent, Apo. IWP-4-2 possessed medium slender grains similar to the recurrent parent, IWP. Based on its drought tolerance and grain type IWP-4-2 can also be used as donor parent for developing climate resilient rice variety suitable to conditions obtaining in Tamil Nadu.

Prioritization of feasible physiological parameters in drought tolerance evaluation in sorghum: a grey relational analysis

Identification and evaluation of drought tolerant germplasm is the primary step for sorghum (Sorghum bicolor L. Moench) breeding and utilization under drought conditions. The objective of this study was to use a grey relational analysis to investigate the role of feasible physiological parameters in evaluating drought tolerance in sorghum. Four sorghum varieties were cultivated in pots with two water treatments, including normal watering (75–80% of the soil moisture capacity) and water deficit (45–50% of the soil moisture capacity), which occurred at jointing stage, anthesis and filling stage, respectively. Drought tolerance index of yield was used as the key indicator to evaluate sorghum performance under drought. The grey relational degree of the investigated parameters decreased in the order of transpiration rate, stomatal conductance, photosynthetic rate, soluble sugar content, proline content, relative water content, activity of catalase, activity of superoxide dismutase and activity of peroxidase, implying that drought tolerance for guaranteeing sorghum yield formation was the most related to gas exchange parameters. Water content was a very sensitive parameter of plant growth under drought stress and was more important as compared to the activities of antioxidant enzymes. Results of this research suggested that feasible physiological parameters could be used in the evaluation of drought tolerance to improve the efficiency and accuracy of selection.

Screening of tea progenies for tolerance to drought stress using multivariate statistical techniques

Drought is a recurring problem of tea plantations cultivated under rainfed conditions. Severity and extent of soil moisture stress are critical, as it has diverse effects on tea plants. To evaluate drought tolerance of F1 progenies, an experiment based on alpha-lattice block design with four replications was carried out between 2009 and 2014 at UPASI Experimental Farm, Valparai, India. Statistical methods were used to study the relationship between yield stability index (YSI), physiological and biochemical traits of the progenies, including net photosynthetic rate (Pn) and chlorophyll (Chl) contents (SPAD), cell membrane stability (CMS) at 4 and 40°C, proline and phenylalanine ammonia-lyase (PAL; EC 4.3.1.5) activity. The results showed that CMS, physiological characters and biochemical attributes of field grown F1 progenies showed significant variations at inter and intra cross-levels and superior to their respective parents. There were positive and significant correlation between yield stability index (YSI) and Chl-a (r=0.320, P=0.01), Chl-b (r=0.316, P=0.01), carotenoid (r=0.321, P=0.01), T-Chl (r=0.319, P=0.01), Pn (r=0.319, P=0.01) and PAL (r=0.896, P=0.01) while a negative significant relationship with CMS 40°C (r=−0.153, P=0.05) and proline (r=−0.179; P=0.01). Multiple regression analysis indicated that the prediction model for YSI accounts 91.7% of the total variation within the measured traits. The results of stepwise linear regression analysis indicated that PAL (R2=80.1%), Chl-a (R2=87.1%), CMS 4°C (R2=90.4%) and proline (R2=91.2%) were the most relevant physiological traits related to YSI. Principal components PC-1 and PC-2 justify 71.50% of the total variance. Based on the coefficients of the PC-1 (proline; 52.90%) and PC-2 (CMS 40°C; 18.50%) progenies could be considered for conferring tolerance or susceptible accessions. Based on the results, it is reasonable to assume that high YSI of F1 progenies could be identified as breeding materials with high proline, PAL and CMS 40°C.

Evaluation of drought tolerance some of spring canola cultivars (Brassica napus L)

Evaluation of drought tolerance some of spring canola cultivars (Brassica napus L)

Drought tolerance evaluation of tobacco plants transformed with different set of genes under laboratory and field conditions

Although extensive studies have demonstrated that many drought-responsive genes confer drought tolerance to plants, comparisons of the drought tolerance capabilities conferred by different genes under various natural conditions have seldom been reported. We evaluated and compared the effects of two sets of transgenes, the drought-responsive genes (AtDREB1B and AtCBL1) and the root architecture-regulated genes (iaaM and AtCKX), on drought tolerance in Nicotiana tabacum plants subjected to different conditions. The expression of AtCKX3 driven by a root-specific promoter PYK10 (designated hereafter as P10; P10:AtCKX3), 35S:AtCKX3, or P10:iaaM promoted root growth and development. Compared to plants harboring P10:AtCKX3, 35S:AtCKX3, P10:iaaM, or the empty vector, those carrying 35S:AtDREB1B, 35S:AtCBL1, or 35S:iaaM exhibited increased drought tolerance under laboratory-controlled conditions. Conversely, in field conditions, plants transformed with 35S:AtDREB1, 35S:AtCBL1, or 35S:iaaM were sensitive to drought stress. Under field conditions, drought stress dramatically reduced the growth and seed production of plants harboring 35S:AtDREB1B, 35S:AtCBL1, 35S:iaaM, or the empty vector, whereas it had little effect on plants carrying P10:AtCKX3, 35S:AtCKX3, or P10:iaaM. This study demonstrates that a plant’s tolerance to drought stress changes with environmental conditions, and our results indicates that manipulating the expression of genes that control root architecture may be important for engineering plants with improved drought tolerance in natural conditions.

Transpiration efficiency versus growth: Exploring the banana biodiversity for drought tolerance

Water shortage is the largest limiting abiotic factor in agriculture and will aggravate in the future. Because of the complexity there is not one conclusive definition of drought. Therefore it is challenging to identify the right parameter and stress intensity for drought tolerance evaluation. This paper contributes to tackle this challenge by exploring the effect of water deficit on transpiration efficiency (TE). In total, six triploid banana (Musa spp.) cultivars were characterized during well-watered and two different water deficit conditions. We developed a concept to evaluate both TE and growth, since selection for high TE is often associated with slow growth. TE increased for all cultivars when stressed and a clear genotypic variation in TE during water deficit could be discerned. ‘Kayinja’ (ABB) and ‘Sukali Ndizi’ (AAB) were ranked as the most efficient cultivars and the East African highland cultivar ‘Mpologoma’ (AAA) exhibited the least transpiration efficient phenotype. Selection for high TE did not lead to selection of slow growers during well-watered and mild stress conditions. High TE varieties are thus projected to bring forth good yield under well-watered and water deficit conditions.

Using Different Statistical Procedures for Evaluating Drought Tolerance Indices of Bread Wheat Genotypes

Using Different Statistical Procedures for Evaluating Drought Tolerance Indices of Bread Wheat Genotypes

Evaluation of drought tolerance in new Bulgarian sweet corn genotypes with using stress tolerance indices

Two inbred lines and their heterotic F1 hybrid of sweet corn (Zea mays L. var. rugosa Bonaf.) were evaluated to assess their reaction for PEG-mediated water stress at the seedling stage in terms of various physiological and biochemical traits. Water potentials were: zero as control and -0.6, -0.9, -1.2 and -1.5 MPa as treatments. Stress- determining parameters such as proline content, malondiadehyde, and hydrogen peroxide were measured. In water stress, the germination was inversely proportional to the Polyethylene glycol concentrations in all three genotypes; roots and shoots length, fresh and dry weight decreased with an increasing of polyethylene glycol concentration. Malondiadehyde, proline, and hydrogen peroxide were found to be increased at different osmotic gradients in comparison to control. The data observed in the experiments revealed that the line C-6 might be used as a very promising parent to breed and select new drought tolerant sweet corn hybrids. Such a suggestion needs to be further explored by involving a larger set of sweet corn lines and hybrids.

Platform Development for Drought Tolerance Evaluation of Wheat in France

IntroductionDrought is projected to be an increasing problem for wheat in France. We provide some key figures on current and projected drought stress in France. Evaluating drought tolerance is a complex task. Climate variability can lead to very different drought stress conditions in field experiments. The importance of genotype by environment interactions under drought also requires that trial environments be related to the types of drought prevalent in each target population of environments. We present the framework developed at Arvalis to deal with these complex interactions. Materials and methods-Two dedicated platforms have been developed to carry out genotype evaluations for association genetics panels. A field platform has been in operation for 5 years. Tools developed on the platform include a microplot scale soil characterization and the PhenoMobile automated phenotyping system. The second, under construction, is PhenoField, including automated rain-out shelters and phenotyping systems.-A network of field trials is run on a subset of varieties to identify trait x environment interactions for drought response.-Climatological analysis using a water balance model is carried out across France. Results-The diversity of drought stress intensities over 5 years in the field platform is presented and compared to the climatological analysis of drought in France.-The correlation of traits, for example Carbon Isotope Discrimination, to perform in diverse drought environments is assessed throughout the field network.-The use of microplot scale soil characterization significantly improves precision and heritability on our panel evaluation.-An update on the development of PhenoMobile and PhenoField systems is given. Discussion-Drought tolerance evaluation requires an integration of multiple tools. We combine well characterized sites with high throughput capacities to trial networks and climatological analysis to extrapolate results.

Evaluation of drought tolerance of winter bread wheat genotypes underdrip irrigation and rain-fed conditions

To evaluate the genetic diversity in 48 winter bread wheat genotypes originating from different countries, an experiment based on randomized complete block design with 4 replications was carried out in drip irrigation and rain-fed conditions at the field station of the Transitional Zone Agricultural Research Institute, Eskişehir, Turkey in 2011 and 2012. Based on grain yield under rain-fed and irrigated conditions, drought tolerance indices, i.e. stress susceptibility index (SSI), stress tolerance index (STI), tolerance index (TOL), mean productivity (MP), and geometric mean productivity (GMP), were calculated to identify genotypes with better yield and drought tolerance. Analysis of variance indicated that there were highly significant differences among the genotypes with regard to all the traits under the two experimental conditions. The correlation coefficients showed that STI, MP, and GMP were the most desirable selection criteria for high yielding and drought tolerant genotypes. Based on principle component analysis and biplot, genotypes numbered as 6, 11, 26, 41, 45, and 47 were susceptible genotypes. The genotypes numbered as 4, 12, 17, 24, 27, 28, 34, 35, 36, 38, and 42 were more stable under rain-fed conditions, while genotypes numbered as 9, 29, 31, and 44 were highly adapted to the irrigated conditions. Cluster analysis classified the genotypes into 3 groups: resistant, susceptible, and tolerant to drought conditions. In conclusion, this study showed that drought stress reduced the yield of some genotypes, while others were tolerant to drought, suggesting genetic variability of drought tolerance in this material. Therefore, breeders can select stress-resistant wheat genotypes based on the MP, GMP, and STI indices.

Differences between soybean genotypes in physiological response to sequential soil drying and rewetting

Soybean genotypes show diverse physiological responses to drought, but specific physiological traits that can be used to evaluate drought tolerance have not been identified. In the present study we investigated physiological traits of soybean genotypes under progressive soil drying and rewetting, using a treatment mimicking field conditions. After a preliminary study with eight soybean genotypes, two drought-tolerant genotypes and one susceptible genotype were grown in the greenhouse and subjected to water restriction. Leaf expansion rate, gas exchange, water relation parameters, total chlorophyll (Chl), proline contents of leaves, and root xylem pH were monitored in a time course, and plant growth and root traits were measured at the end of the stress cycle. Drought-tolerant genotypes maintained higher leaf expansion rate, net photosynthetic rate (Pn), Chl content, instantaneous water use efficiency (WUEi), % relative water content (RWC), water potential (ψw), and turgor potential (ψp) during progressive soil drying and subsequent rewetting than the susceptible genotypes. By contrast, stomatal conductance (gs) and transpiration rate (Tr) of tolerant genotypes declined faster owing to dehydration and recovered more sharply after rehydration than the same parameters in susceptible ones. Water stress caused a significant increase in leaf proline level and root xylem sap pH of both genotypes but tolerant genotypes recovered to pre-stress levels more quickly after rehydration. Tolerant genotypes also produced longer roots with higher dry mass than susceptible genotypes. We conclude that rapid perception and adjustment in response to soil drying and rewetting as well as the maintenance of relatively high Pn, %RWC, and root growth constitute the mechanisms by which drought-tolerant soybean genotypes cope with water stress.

Evaluation of Drought Tolerance in Safflower Genotypes Based on Drought Tolerance indices

Among the different environmental stresses, drought is the constraint that induces a highly negative effect on crop production. In order to identify drought tolerant genotypes, an experiment was conducted in a randomized complete block design with three replications under rainfed and irrigated conditions during 2011-2012 cropping season. Seven drought resistance indices including Stress Tolerance Index (STI), Tolerance Index (TOL), Stress Susceptibility index (SSI), Mean Productivity (MP), Geometric Mean Productivity (GMP), Yield Index (YI) and Yield Stability Index (YSI) were calculated for each genotype based on grain yield under stress and normal conditions. Analysis of variation showed significant difference among genotypes in the terms of grain yield under rainfed and irrigated conditions. Result of correlation analysis between grain yield in both conditions and calculated drought resistance indices revealed that STI, MP, GMP and YI were the best indices for identifying high yielding genotypes in both conditions (drought tolerant genotypes). Gabriel Biplot Multivariate chart showed that ‘Syrian’, ‘PI-537530’ and ‘PI-537636-S’ genotypes relatively identified as drought tolerant and ‘Hartman’, ‘Gila’, ‘PI-537636’, ‘PI-537598’, ‘LRV-51-51’ and ‘Yenice’ genotypes identified as susceptible genotypes. Cluster analysis based on grain yield and drought tolerance indices recognized the genotypes into four clusters, so that this result was consistent with biplot analysis.

Two Soybean Plant Introductions Display Slow Leaf Wilting and Reduced Yield Loss under Drought

AbstractDue to high costs of irrigation, limited availability of irrigation water in many locations and/or lack of irrigation capabilities, genetic improvement for drought tolerance is an effective method to reduce yield loss in soybean [Glycine max (L.) Merr.]. Slow wilting and minimal yield reduction under drought are important traits in evaluating drought tolerance. Two maturity group III soybean plant introductions (PIs, PI 567690 and PI 567731) and two elite cultivars (DKB38‐52 and Pana) were evaluated with and without irrigation on a sandy soil. Drought was imposed by withholding irrigation at full bloom and continued until moderate wilting was shown by the fast leaf wilting in the check cultivar, Pana. Then, irrigation was resumed until maturity. Genotypes were scored for leaf wilting during the stress period, and yields were assessed at the end of the growing season and used to calculate a drought index. Yields of the exotic PIs were lower than those of the checks under both drought and well‐watered conditions. However, the PIs exhibited significantly lower wilting and less yield loss under drought (higher drought index) than check cultivars. The two PIs may have useful genes to develop drought‐tolerant germplasm and cultivars and maybe useful in genetic and physiological studies to decipher mechanisms responsible for improving yield under limited water availability.