Drought Tolerance Traits Research Articles

Model-assisted ideotyping reveals trait syndromes to adapt viticulture to a drier climate.

Climate change is challenging the resilience of grapevine (Vitis), one of the most important crops worldwide. Adapting viticulture to a hotter and drier future will require a multifaceted approach including the breeding of more drought-tolerant genotypes. In this study, we focused on plant hydraulics as a multi-trait system that allows the plant to maintain hydraulic integrity and gas exchange rates longer under drought. We quantified a broad range of drought-related traits within and across Vitis species, created in silico libraries of trait combinations, and then identified drought tolerant trait syndromes. By modeling the maintenance of hydraulic integrity of current cultivars and the drought tolerant trait syndromes, we identified elite ideotypes that increased the amount of time they could experience drought without leaf hydraulic failure. Generally, elites exhibited a trait syndrome with lower stomatal conductance, earlier stomatal closure, and a larger hydraulic safety margin. We demonstrated that, when compared with current cultivars, elite ideotypes have the potential to decrease the risk of hydraulic failure across wine regions under future climate scenarios. This study reveals the syndrome of traits that can be leveraged to protect grapevine from experiencing hydraulic failure under drought and increase drought tolerance.

Molecular and morpho-agronomic traits for vegetative stage drought tolerance in some rainfed elite rice lines

Selection of drought-tolerant rice genotypes is still one of the most vital challenges in rice research and the use of molecular markers may offer a promising approach to fast track the selection and development of drought-tolerant rice. The aim of our study is to identify drought-tolerant traits, in selected rainfed elite rice lines, expressed during drought stress at the vegetative stages 20-32 DAS and 30-42 DAS. The study also validated the presence of SSR markers linked to drought tolerance. All morpho-agronomic traits examined in the study were significantly affected by drought, except for root length during 30-42 DAS of drought imposition. Drought significantly reduced the plant height, number of tillers, leaf area, and root number resulting in a significant reduction in root and shoot dry weight. On the other hand, an increase in total nodal root length was observed in all test genotypes except for AL-55, AL-97, and susceptible check PSB Rc82 under both drought conditions. All parameters examined in this study are useful traits for drought tolerance in rice, however responses might be genotype-dependent. The highest correlation was shown by root:shoot ratio (r=0.94, r=0.78) at 20 DAS and (r=0.89, r=0.67) at 30 DAS under well-watered and drought conditions, respectively. Seven amplified markers were present in the test genotypes except for RM 525, RM 60, RM 201, RM 1141. These four markers were absent in the drought-susceptible check PSB Rc82, hence, these markers may be used in selecting drought-tolerant genotypes through marker-assisted selection.

Water availability dictates how plant traits predict demographic rates.

A major goal in ecology is to make generalizable predictions of organism responses to environmental variation based on their traits. However, straightforward relationships between traits and fitness are rare and likely to vary with environmental context. Characterizing how traits mediate demographic responses to the environment may enhance the predictions of organism responses to global change. We synthesized 15 years of demographic data and species-level traits in a shortgrass steppe to determine whether the effects of leaf and root traits on growth and survival depended on seasonal water availability. We predicted that (1) species with drought-tolerant traits, such as lower leaf turgor loss point (TLP) and higher leaf and root dry matter content (LDMC and RDMC), would be more likely to survive and grow in drier years due to higher wilting resistance, (2) these traits would not predict fitness in wetter years, and (3) traits that more directly measure physiological mechanisms of water use such as TLP would best predict demographic responses. We found that graminoids with more negative TLP and higher LDMC and RDMC had higher survival rates in drier years. Forbs demonstrated similar yet more variable responses. Graminoids grew larger in wetter years, regardless of traits. However, in both wet and dry years, graminoids with more negative TLP and higher LDMC and RDMC grew larger than less negative TLP and low LDMC and RDMC species. Traits significantly mediated the impact of drought on survival, but not growth, suggesting that survival could be a stronger driver of species' drought response in this system. TLP predicted survival in drier years, but easier to measure LDMC and RDMC were equal or better predictors. These results advance our understanding of the mechanisms by which drought drives population dynamics, and show that abiotic context determines how traits drive fitness.

Multiple-trait analyses improved the accuracy of genomic prediction and the power of genome-wide association of productivity and climate change-adaptive traits in lodgepole pine

BackgroundGenomic prediction (GP) and genome-wide association (GWA) analyses are currently being employed to accelerate breeding cycles and to identify alleles or genomic regions of complex traits in forest trees species. Here, 1490 interior lodgepole pine (Pinus contorta Dougl. ex. Loud. var. latifolia Engelm) trees from four open-pollinated progeny trials were genotyped with 25,099 SNPs, and phenotyped for 15 growth, wood quality, pest resistance, drought tolerance, and defense chemical (monoterpenes) traits. The main objectives of this study were to: (1) identify genetic markers associated with these traits and determine their genetic architecture, and to compare the marker detected by single- (ST) and multiple-trait (MT) GWA models; (2) evaluate and compare the accuracy and control of bias of the genomic predictions for these traits underlying different ST and MT parametric and non-parametric GP methods. GWA, ST and MT analyses were compared using a linear transformation of genomic breeding values from the respective genomic best linear unbiased prediction (GBLUP) model. GP, ST and MT parametric and non-parametric (Reproducing Kernel Hilbert Spaces, RKHS) models were compared in terms of prediction accuracy (PA) and control of bias.ResultsMT-GWA analyses identified more significant associations than ST. Some SNPs showed potential pleiotropic effects. Averaging across traits, PA from the studied ST-GP models did not differ significantly from each other, with generally a slight superiority of the RKHS method. MT-GP models showed significantly higher PA (and lower bias) than the ST models, being generally the PA (bias) of the RKHS approach significantly higher (lower) than the GBLUP.ConclusionsThe power of GWA and the accuracy of GP were improved when MT models were used in this lodgepole pine population. Given the number of GP and GWA models fitted and the traits assessed across four progeny trials, this work has produced the most comprehensive empirical genomic study across any lodgepole pine population to date.

Drought Stress-induced Impact on Morpho-physiological Traits in Maize Landraces of Kashmir

Background: Drought is the critical abiotic stress constraining the productivity of maize and lack of germplasm possessing drought tolerance results in low maize productivity in Kashmir. Because only 15% of the land in Kashmir Valley is irrigated and 85% of the land is rainfed, maize landrace evaluation for drought desirable traits becomes important. Methods: To identify elite genotypes for drought tolerance, seventy maize landraces designated as K-L 1 to K-L 70 from Kashmir were evaluated for morpho-physiological traits: shoot height, shoot biomass, root depth, root biomass allocation, shoot to total biomass, root to total biomass, relative water content, canopy temperature, cell membrane stability and chlorophyll content. Result: A significant decrease in root and shoot traits, relative water content, cell membrane stability, chlorophyll content and a significant increase in canopy temperature was recorded under drought conditions. The evaluation led to identifying landraces exhibiting desirable traits for drought tolerance that would prove useful for further crop improvement.

Screening cotton cultivars under induced water-deficit stress in controlled environments and field settings: expression of drought tolerance traits

ABSTRACT Cotton (Gossypium hirsutum L.) is often grown in climates of intermittent drought conditions. Plants that limit transpiration rates (TRs) when initially exposed to water-deficit stress will preserve water for use later during critical growth stages. Two traits resulting in conservative TRs are TR limitations under soil drying and high vapor pressure deficit (VPD, >2.5 kPa). The objective of this study was to assess the performance of four contrasting cotton cultivars and their TRs under induced water stresses. Three studies were conducted to test (i) the early stomatal closure under soil drying in a greenhouse, (ii) the TR to varying VPD levels in a growth chamber, and (iii) the stomatal conductance (gs), wilting score, specific leaf area (SLA), relative water content (RWC), and yield in an extreme field environment. Significant differences in the fraction of transpirable soil water threshold (FTSW threshold) were detected among cultivars in the greenhouse. The FTSW threshold among cultivars ranged from 0.29 to 0.39. Under varying VPD levels, only PHY 400 W3FE expressed a limited TR (TRlim) with increasing VPD at 1.6 kPa. In the field study, differences in gs, wilting score, RWC, SLA, and lint yield were observed among cultivars within the water limited treatments (i.e. rainout and rainfed). PHY 400 W3FE had the lowest wilting score compared to other cultivars. Under the rainout treatment, PHY 400 W3FE yielded 37% higher than PHY 500 W3FE. Results indicate a trend in water saving potential among cotton cultivars, given the differences in their TR sensitivity to water-deficit stress conditions.

Phenotypic evaluation of agronomic and root related traits for drought tolerance in recombinant inbred line population derived from a chickpea cultivar (C. arietinum L.) and its wild relative (C. reticulatum).

The online version contains supplementary material available at 10.1007/s12298-022-01218-z.

Selecting putative drought-tolerance markers in two contrasting soybeans

Identifying high-yield genotypes under low water availability is essential for soybean climate-smart breeding. However, a major bottleneck lies in phenotyping, particularly in selecting cost-efficient markers associated with stress tolerance and yield stabilization. Here, we conducted in-depth phenotyping experiments in two soybean genotypes with contrasting drought tolerance, MUNASQA (tolerant) and TJ2049 (susceptible), to better understand soybean stress physiology and identify/statistically validate drought-tolerance and yield-stabilization traits as potential breeding markers. Firstly, at the critical reproductive stage (R5), the molecular differences between the genotype’s responses to mild water deficit were explored through massive analysis of cDNA ends (MACE)-transcriptomic and gene ontology. MUNASQA transcriptional profile, compared to TJ2049, revealed significant differences when responding to drought. Next, both genotypes were phenotyped under mild water deficit, imposed in vegetative (V3) and R5 stages, by evaluating 22 stress-response, growth, and water-use markers, which were subsequently correlated between phenological stages and with yield. Several markers showed high consistency, independent of the phenological stage, demonstrating the effectiveness of the phenotyping methodology and its possible use for early selection. Finally, these markers were classified and selected according to their cost-feasibility, statistical weight, and correlation with yield. Here, pubescence, stomatal density, and canopy temperature depression emerged as promising breeding markers for the early selection of drought-tolerant soybeans.

Mixing trait-based corn (Zea mays L.) cultivars increases yield through pollination synchronization and increased cross-fertilization

Abiotic stress such as high temperature at flowering is one of many conditions reducing yield of corn (Zea mays L.). Mixing corn cultivars with diverse functional traits increases within-crop diversity and provides a potential means of mitigating yield losses under stress conditions. We conducted a three-year field study to investigate the effects of cultivar mixtures on kernel setting rate, pollen sources, and yield. This study consisted of six treatments, including two high temperature-tolerant (HTT) monocrops of WK702 and DH701, two high temperature-sensitive (HTS) monocrops of DH605 and DH662, and two HTT–HTS mixtures of WK702-DH605 and DH701-DH662. The anthesis–silking interval (ASI) was 0.9–1.6 days shorter in mixtures than in monocrops. Kernel setting rate was increased in mixtures (86.4%–88.7%) compared with those in monocrops (74.7%–84.1%) as a result of synchrony and complementarity of pollination. Grain yields of the HTT–HTS mixtures increased by 13.3%–18.7%, equivalent to 1169 to 1605 kg ha−1, in comparison with HTS corn monocrops. The results of SSR markers showed that cross-fertilization percentage in corn cultivar mixtures ranged from 29.3% to 47.8%, partially explaining yield improvement. Land equivalent ratio (LER) was 1.12 for corn mixtures and the partial land equivalent ratio (e.g., > 0.5) showed the complementary benefits in corn mixtures. The results indicated that mixing corn cultivars with diverse flowering and drought-tolerance traits increased yields via pollination synchrony.

Wheat Production in Drought-Prone Agro-Ecologies in Ethiopia: Diagnostic Assessment of Farmers’ Practices and Sustainable Coping Mechanisms and the Role of Improved Cultivars

Wheat (Triticum aestivum L.) is traditionally cultivated under drought-affected and low-input agro-ecologies in sub-Saharan Africa, including Ethiopia. Wheat productivity in these agro-systems is considerably low (<2.4 t/ha) due to climate change-induced drought and heat stress, a lack of modern production technologies, including climate-smart varieties, and an array of biotic and abiotic factors. The objective of this study was to determine the potential of wheat production in drought-prone agro-ecologies and to assess farmers’ practices and sustainable coping mechanisms and the role of improved cultivars in Ethiopia. A participatory rural appraisal (PRA) study was conducted involving 170 randomly selected wheat farmers in the drier areas of Arsi Zone of the Oromia Regional State. Results showed that wheat and tef (Eragrostis tef Zucc.) and barley (Hordeum vulgare L.) were the most widely grown cereal crops in the study areas as the primary food source and cash income. Yield losses varying from 63.1 to 73.8% were reported by farmers due to drought stress occurring mainly during grain filling stage. The majority of the respondent farmers (>50%) planted wheat in early July using the broadcasting method. Their land was of medium fertility, and the application of inorganic fertilizer was suboptimal. Due to crop failures by intense drought conditions in the study areas, above 50% of the respondent farmers had not expressed coping strategies against drought stress except resorting to government food aid. However, about 22% of the respondent farmers reported improved agronomic practices, such as the cultivation of early maturing wheat varieties and soil and water conservation methods as sustainable solutions to mitigate against drought. Therefore, current and future wheat breeding in Ethiopia should target drought and heat stress tolerance and adaptive crop traits as ideal coping strategies under low input agriculture systems for sustainable wheat production and productivity.

Association Mapping for Drought Tolerance and Yield-Related Traits in Cowpea Accessions Using Genome-Wide Association Study and Population Structure Analysis

Cowpea is an important drought-tolerant crop that is grown mainly in Africa. The objective of this study was to conduct association mapping of drought tolerance phenotype with seedling and yield-related traits in cowpeas. A total of 60 cowpea accessions were used in the study. Single-nucleotide polymorphisms (SNPs) were discovered through genotyping-by-sequencing (GBS). In the primary pipeline analysis, fragments of poor-quality sequences with reproducibility below 90% and read depths lower than 3.5 for SNPs or 5 for presence–absence markers were filtered out. Approximately 2.5 million sequences per barcode/sample were identified and used in marker calling. Association mapping was conducted using single-marker regression (SMR) in Q Gene, and the general linear model (GLM) and mixed linear model (MLM) built in TASSEL v5.0. The population of the cowpea accessions was analyzed using STRUCTURE 2.3.4. Inferred number of populations (ΔK) of cowpea accessions grown in the greenhouse and glasshouse were six (6) and seven (7), respectively. Approximately 2.5 million sequences per barcode/sample were identified and used in marker calling. The total number of SNPs in the raw file was 438,198. After a quality control procedure, a variant call format (vcf). One SNP marker, was associated with number of pods (NP) with a p value < 0.001 while fifty SNP markers, were associated with pod weight (PWT) at p < 0.001. The same number of four SNP markers, were associated with average seeds per pod (AVSPD) at p < 0.001 and also with pod length (PL). Five SNP markers, were associated with pod width (PWDTH) at p < 0.001. Major differences among the significantly associated SNPs were observed in the two environments which were under different temperature conditions. The 65 SNP markers identified can be used in cowpea molecular breeding to select for drought tolerant phenotypes in cowpea through marker assisted selection (MAS).

Characterizing and designing promoter of gene \(\textit{ZmDREB2.7}\) into plant expression vector

In the regulation of gene expression, particularly abiotic-stress tolerance characteristics in plants, inducible promoters play an essential role in ensuring the endurance and productivity of crops. In several previous studies, the ZmDREB2.7 gene and some DNA polymorphisms in its promoter have been shown to enhance drought tolerance traits in maize (Zea mays L.). With the goal of creating a strong drought-tolerant promoter region derived from maize, in this study, the 1 kilobase 5’-upstream region of the ZmDREB2.7 coding sequence from the drought resistant maize line Tevang1 was isolated and characterized. Essential putative cis-regulatory elements (as TATA box or CAAT box) and other elements that regulate drought tolerant properties (as RY/G box, ABRE element or MYB core) were investigated. After that, we designed the transgenic plant vector containing the isolated promoter and the ZmDREB2.7 gene which were isolated in our earlier study. The promoter segment was removed 20 nucleotides ahead of the transcription start site and transferred into the recombinant pZY vector containing the ZmDREB2.7 gene. In conclusion, we created a recombinant vector containing the modified ZmDREB2.7 promoter and the ZmDREB2.7 gene segment derived from maize. This is a promising resource for the creation of a transgenic cultivar with effective resistance to dry stress in the future. Besides, we will keep on examining other potential genetic regions and promoters to diversify sources of genetic materials as well as understand deeper the stress-resistant transgenic plants.

INSERTION OF COLD SHOCK GENE FROM ESCHERICHIA COLI IN WHEAT PLANTS TO PRODUCE DROUGHT TOLERANT PROPERTIES

Drought is a threat that affects plant growth and development. Wheat crops are very sensitive to heat and drought stress during flowering and grain development, which negatively affects grain yield and quality. Wheat with drought tolerant properties is a genetically modified plant obtained by inserting a cold shock protein gene from Escherichia coli so that it can increase the ability of wheat to adapt to drought. This literature review aims to provide information about the role of cold shock protein gene insertion from Escherichia coli in wheat plants to produce drought tolerant traits. The results of the literature review showed that the CspA gene from Escherichia coli inserted into DNA could increase gene expression by changing the nucleotides in the DNA sequence to increase G+C. Gene insertion produces recombinant DNA with specific nucleotide changes. Nucleotide changes were carried out to increase the overall G+C amino acid content without changing the existing CspA and CspB protein sequences. These changes played an important role in helping wheat adapt to drought. The leaves on the transgenic wheat showed a decrease in the rate of water loss because the stomata in these plants closed faster than in the ordinary wheat so that the transgenic wheat became more drought tolerant.

High-throughput phenotyping reveals differential transpiration behaviour within the banana wild relatives highlighting diversity in drought tolerance.

Crop wild relatives, the closely related species of crops, may harbour potentially important sources of new allelic diversity for (a)biotic tolerance or resistance. However, to date, wild diversity is only poorly characterized and evaluated. Banana has a large wild diversity but only a narrow proportion is currently used in breeding programmes. The main objective of this study was to evaluate genotype‐dependent transpiration responses in relation to the environment. By applying continuous high‐throughput phenotyping, we were able to construct genotype‐specific transpiration response models in relation to light, VPD and soil water potential. We characterized and evaluated six (sub)species and discerned four phenotypic clusters. Significant differences were observed in leaf area, cumulative transpiration and transpiration efficiency. We confirmed a general stomatal‐driven ‘isohydric’ drought avoidance behaviour, but discovered genotypic differences in the onset and intensity of stomatal closure. We pinpointed crucial genotype‐specific soil water potentials when drought avoidance mechanisms were initiated and when stress kicked in. Differences between (sub)species were dependent on environmental conditions, illustrating the need for high‐throughput dynamic phenotyping, modelling and validation. We conclude that the banana wild relatives contain useful drought tolerance traits, emphasising the importance of their conservation and potential for use in breeding programmes.

Effect of exogenous abscisic acid on growth, biochemical changes and antioxidant enzyme activities in black gram [Vigna mungo (L.) Hepper] under drought

Drought stress is a significant limitation to the production and yield of black gram [Vigna mungo (L.) Hepper] and abscisic acid plays a subtle role in the biosynthetic pathway during drought stress. The present study examined the morphology, biochemical, relative water content and antioxidant activities of black gram plants treated with various abscisic acid (ABA) levels under drought conditions. The ABA at 50 ppm concentration showed promising recovery of morphological characters compared to other concentrations. The photosynthetic pigments, biochemical constituents, malondialdehyde and antioxidant enzymes (CAT, POD, SOD and APX) were active at 50 ppm. Infrared Spectroscopic (IR) analysis of black gram leaves in a bandwidth ranging from 400 to 4000 cm-1 revealed a change in metabolites under drought stress and exogenous ABA application. The FTIR spectroscopy results warrant that the expression of functional organic compounds in the drought response of black gram can aid in the discovery of new drought-tolerant traits. As a result, ABA-responsive cultivars can cultivate and produce drought-resistant black gram varieties in arid and semi-arid climates.

Climate Change Impact on Wheat Performance-Effects on Vigour, Plant Traits and Yield from Early and Late Drought Stress in Diverse Lines.

Global climate change is threatening wheat productivity; improved yield under drought conditions is urgent. Here, diverse spring-wheat lines (modern, old and wheat-rye introgressions) were examined in an image-based early-vigour assay and a controlled-conditions (Biotron) trial that evaluated 13 traits until maturity. Early root vigour was significantly higher in the old Swedish lines (root length 8.50 cm) and introgressed lines with 1R (11.78 cm) and 1RS (9.91 cm) than in the modern (4.20 cm) and 2R (4.67 cm) lines. No significant correlation was noted between early root and shoot vigour. A higher yield was obtained under early drought stress in the 3R genotypes than in the other genotype groups, while no clear patterns were noted under late drought. Evaluating the top 10% of genotypes in terms of the stress-tolerance index for yield showed that root biomass, grains and spikes per plant were accountable for tolerance to early drought, while 1000-grain weight and flag-leaf area were accountable for tolerance to late drought. Early root vigour was determined as an important focus trait of wheat breeding for tolerance to climate-change-induced drought. The responsible genes for the trait should be searched for in these diverse lines. Additional drought-tolerance traits determined here need further elaboration to identify the responsible genes.

Multiparent-Derived, Marker-Assisted Introgression Lines of the Elite Indian Rice Cultivar, 'Krishna Hamsa' Show Resistance against Bacterial Blight and Blast and Tolerance to Drought.

Major biotic stresses viz., bacterial blight (BB) and blast and brown plant hopper (BPH) coupled with abiotic stresses like drought stress, significantly affect rice yields. To address this, marker-assisted intercross (IC) breeding involving multiple donors was used to combine three BB resistance genes—xa5, xa13 and Xa21, two blast resistance genes—Pi9 and Pi54, two BPH resistance genes—Bph20 and Bph21, and four drought tolerant quantitative trait loci (QTL)—qDTY1.1, qDTY2.1, qDTY3.1 and qDTY12.1—in the genetic background of the elite Indian rice cultivar ‘Krishna Hamsa’. Three cycles of selective intercrossing followed by selfing coupled with foreground selection and phenotyping for the target traits resulted in the development of 196 introgression lines (ILs) with a myriad of gene/QTL combinations. Based on the phenotypic reaction, the ILs were classified into seven phenotypic classes of resistance/tolerance to the following: (1) BB, blast and drought—5 ILs; (2) BB and blast—10 ILs; (3) BB and drought—9 ILs; (4) blast and drought—42 ILs; (5) BB—3 ILs; (6) blast—84 ILs; and (7) drought—43 ILs; none of the ILs were resistant to BPH. Positive phenotypic response (resistance) was observed to both BB and blast in 2 ILs, BB in 9 ILs and blast in 64 ILs despite the absence of corresponding R genes. Inheritance of resistance to BB and/or blast in such ILs could be due to the unknown genes from other parents used in the breeding scheme. Negative phenotypic response (susceptibility) was observed in 67 ILs possessing BB-R genes, 9 ILs with blast-R genes and 9 ILs harboring QTLs for drought tolerance. Complex genic interactions and recombination events due to the involvement of multiple donors explain susceptibility in some of the marker positive ILs. The present investigation successfully demonstrates the possibility of rapid development of multiple stress-tolerant/resistant ILs in the elite cultivar background involving multiple donors through selective intercrossing and stringent phenotyping. The 196 ILs in seven phenotypic classes with myriad of gene/QTL combinations will serve as a useful genetic resource in combining multiple biotic and abiotic stress resistance in future breeding programs.

Root and Rhizosphere Processes under Drought: Digging Deeper to Enhance Ecosystem Resilience

Root and Rhizosphere Processes under Drought: Digging Deeper to Enhance Ecosystem Resilience

Physiological and Yield Responses of Selected Mungbean Genotypes to Terminal Drought

Extreme drought conditions have been a major limiting factor in legume production worldwide. The development of drought-resilient crops should help mitigate adverse effects of unfavorable environmental conditions such as drought; however, initial characterization is necessary to ensure that the germplasm has the essential genetic variation for drought tolerance. In this study, a field trial was conducted to characterize drought response and potential drought tolerance of 100 mungbean genotypes through the evaluation of several physiological parameters and seed yield. The genotypes were subjected to terminal drought stress before flowering (~ 30 d after planting), reducing soil moisture content (SMC) from 25.0–30.0% to 13.0–15.0% during treatment imposition. Significant differences were observed between mungbean genotypes for total chlorophyll content (Chl), total scavenging activity (SA), electrolyte leakage (EC), and chlorophyll fluorescence (Fv/Fm) during drought. Furthermore, by transforming each physiological parameter into principal components (PCs) via principal component analysis (PCA), five distinct clusters were generated. Based on their physiological response and seed yield, Clusters I and II were identified as potential drought susceptible group, Cluster III was moderately susceptible, and Clusters IV and V were identified as the potential drought-tolerant group. Correlation analysis and PCA also demonstrated the significant relationship among several key traits for drought tolerance such as chlorophyll content, electrolyte leakage, and antioxidant scavenging to chlorophyll fluorescence – suggesting the suitability of fluorescence parameter in mungbean mass screening for drought tolerance. Although weak correlation between physiological parameters to seed yield was present (0.3 <│r│< 0.5), correlations among each physiological parameter were moderately strong (0.5 <│r│< 0.7). The findings suggest that a physiological characterization during initial screening for drought tolerance was an effective approach in identifying possible sources of drought tolerance traits complementary with yield- related traits. The evaluation of chlorophyll fluorescence, scavenging activity, electrolyte leakage, and chlorophyll content was enough to differentiate and characterize the drought response of several mungbean genotypes and will be vital in the development of climate-resilient crops.

Genome-wide identification and expression analysis of theGRAS gene family in response to drought stress in chickpea (Cicer arietinum L.).

The online version contains supplementary material available at 10.1007/s13205-021-03104-z.