scholarly journals Evaluation of Drought Tolerance of the Vietnamese Soybean Cultivars Provides Potential Resources for Soybean Production and Genetic Engineering

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Nguyen Binh Anh Thu ◽  
Quang Thien Nguyen ◽  
Xuan Lan Thi Hoang ◽  
Nguyen Phuong Thao ◽  
Lam-Son Phan Tran
Keyword(s):  
Genetic Engineering ◽  
Drought Tolerance ◽  
Molecular Breeding ◽  
Water Shortage ◽  
Soybean Production ◽  
Soybean Cultivars ◽  
Drought Tolerant ◽  
Relative Water ◽  
Underlying Mechanisms ◽  
Selection Of

Drought is one of the greatest constraints to soybean production in many countries, including Vietnam. Although a wide variety of the newly produced cultivars have been produced recently in Vietnam through classical breeding to cope with water shortage, little knowledge of their molecular and physiological responses to drought has been discovered. This study was conducted to quickly evaluate drought tolerance of thirteen local soybean cultivars for selection of the best drought-tolerant cultivars for further field test. Differences in drought tolerance of cultivars were assessed by root and shoot lengths, relative water content, and drought-tolerant index under both normal and drought conditions. Our data demonstrated that DT51 is the strongest drought-tolerant genotype among all the tested cultivars, while the highest drought-sensitive phenotype was observed with MTD720. Thus, DT51 could be subjected to further yield tests in the field prior to suggesting it for use in production. Due to their contrasting drought-tolerant phenotypes, DT51 and MTD720 provide excellent genetic resources for further studies underlying mechanisms regulating drought responses and gene discovery. Our results provide vital information to support the effort of molecular breeding and genetic engineering to improve drought tolerance of soybean.

Evaluation of diverse cowpea [Vigna unguiculata (L.) Walp.] germplasm accessions for drought tolerance

2019 ◽  
Author(s):  
K.D. Nkoana ◽  
Abe Shegro Gerrano ◽  
E.T. Gwata
Keyword(s):  
Drought Stress ◽  
Drought Tolerance ◽  
Water Content ◽  
Relative Water Content ◽  
Evaluation Method ◽  
Moisture Stress ◽  
Proline Content ◽  
Drought Tolerant ◽  
Relative Water ◽  
Germplasm Accessions

The genetic potential for drought tolerance in cowpea within the small holder sector has not been fully exploited in South Africa. Thus, a drought evaluation experiment was conducted at the ARC-VOP to evaluate 28 cowpea germplasm accessions including two controls viz. IT96D-602 (drought tolerant) and TVU7778 (susceptible to drought) in the drought screening house using plastic box evaluation method in January, 2017. Genotypes raised for three weeks were subjected to 5 weeks of water stress treatment to determine their physiological response through leaf wilting index, relative water content and proline content followed by re-watering to determine genotype (s) with ability to recover from drought stress. Analyses of variance showed highly significant differences in response to moisture stress among the cowpea accessions for the selected physiological traits except for leaf wilting index at week two of drought stress. Stem greenness and recovery appeared to be a reliable indicator of drought tolerant genotypes which was readily observed in Acc1257, Acc1168, Acc2355, IT96D-602 and Acc5352 which also correlated significantly and positively with relative water content and proline content. The genotypes responded differently to drought stress indicating that there is sufficient genetic variability that can be utilized further in breeding for drought stress within the cowpea species.

scholarly journals Differential characterization of physiological and biochemical responses during drought stress in finger millet varieties

2019 ◽  
Author(s):  
Asunta Mukami ◽  
Alex Ngetich ◽  
Cecilia Mweu ◽  
Richard O. Oduor ◽  
Mutemi Muthangya ◽  
...  
Keyword(s):  
Drought Stress ◽  
Water Content ◽  
Relative Water Content ◽  
Finger Millet ◽  
Drought Tolerant ◽  
Early Seedling Growth ◽  
Relative Water ◽  
Early Seedling ◽  
Physiological And Biochemical ◽  
Selection Of

AbstractDrought is the most perilous abiotic stress that affects finger millet growth and productivity worldwide. For the successful production of finger millet, selection of drought tolerant varieties is necessary and critical stages under drought stress, germination and early seedling growth, ought to be fully understood. This study investigated the physiological and biochemical responses of six finger millet varieties (GBK043137, GBK043128, GBK043124, GBK043122, GBK043094 and GBK043050) under mannitol-induced drought stress. Seeds were germinated on sterile soil and irrigated with various concentrations of mannitol (200, 400 and 600 mM) for two weeks. Comparative analysis in terms of relative water content (RWC), chlorophyll, proline, and malondialdehyde (MDA) contents were measured the physiological and biochemical characteristics of drought stress. The results showed that increased level of drought stress seriously decreased germination and early seedling growth of finger millet varieties. However, root growth was increased. In addition, exposition to drought stress triggered a significant decrease in relative water content and chlorophyll content reduction the biochemical parameters assay showed less reduction of relative water content. Furthermore, oxidative damage indicating parameters such as proline concentration and MDA content increased. Varieties GBK043137 and GBK043094 were less affected by drought as shown by significant change in the physiological parameters. Our findings reveal the difference and linkage between the physiological responses of finger millet to drought and are vital for breeding and selection of drought tolerant varieties of finger millet. Further investigations on genomic and molecular to deeply insight the detail mechanisms of drought tolerance in finger millet need to explored.

scholarly journals Use of physiological parameters as fast tools to screen for drought tolerance in sugarcane

2007 ◽  
Vol 19 (3) ◽  
pp. 193-201 ◽  
Author(s):  
Marcelo de A. Silva ◽  
John L. Jifon ◽  
Jorge A.G. da Silva ◽  
Vivek Sharma
Keyword(s):  
Drought Stress ◽  
Drought Tolerance ◽  
Crop Improvement ◽  
Relative Increase ◽  
Physiological Parameters ◽  
Screening Tools ◽  
Leaf Chlorophyll ◽  
Drought Tolerant ◽  
Relative Water ◽  
Leaf Relative Water Content

Drought is one of the major limitations to plant productivity worldwide. Identifying suitable screening tools and quantifiable traits would facilitate the crop improvement process for drought tolerance. In the present study, we evaluated the ability of four relatively physiological parameters (variable-to-maximum chlorophyll a fluorescence ratio, F v/F m; estimated leaf chlorophyll content via SPAD index; leaf temperature, LT; and, leaf relative water content, RWC) to distinguish between drought tolerant and susceptible sugarcane genotypes subjected to a 90-d drought cycle. Eight field-grown genotypes were studied. By 45 d after the onset of treatments, the F v/F m, SPAD index and RWC of drought-stressed plants had declined significantly in all genotypes compared to values at the onset of well-watered treatments. However, the reductions were more severe in leaves of susceptible genotypes. Under drought stress, the tolerant genotypes as a group, maintained higher F v/F m (8%), SPAD index (15%), and RWC (16%) than susceptible genotypes. In general, LT of drought-stressed plants was higher (~4ºC) than that of well-watered plants but the relative increase was greater among drought susceptible genotypes. Under drought stress, LT of tolerant genotypes was on average 2.2ºC lower than that of susceptible genotypes. The results are consistent with the tolerant-susceptible classification of these genotypes and indicate that these tools can be reliable in screening for drought tolerance, with F v/F m, SPAD index and LT having the added advantage of being nondestructive and easily and quickly assessed.

Standardization of screening technique and evaluation of muskmelon genotypes for drought tolerance

2016 ◽  
Vol 16 (1) ◽  
pp. 1-8 ◽  
Author(s):  
Sudhakar Pandey ◽  
Waquar Akhter Ansari ◽  
Neelam Atri ◽  
Bijendra Singh ◽  
Sunil Gupta ◽  
...  
Keyword(s):  
Drought Tolerance ◽  
Chlorophyll Concentration ◽  
Screening Method ◽  
Visual Observation ◽  
Point Scale ◽  
Yield Efficiency ◽  
Commercial Cultivation ◽  
Drought Tolerant ◽  
Root And Shoot Length ◽  
Relative Water

AbstractA five-point drought stress screening methodology for muskmelon based on visual observation has been standardized by modifying an earlier field screening method. The scale (1 to 5), were categorized into five groups, namely, highly drought tolerant (1), drought tolerant (2), average drought tolerant (3), drought susceptible (4) and highly drought susceptible (5). To validate and standardized the technique, 48 genotypes of muskmelon were evaluated for two successive years. Important physiological parameters, i.e.: relative water content (RWC), electrolyte leakage, photosynthetic efficiency (Fv/Fm), chlorophyll concentration index (CCI), root and shoot length were measured and correlated to make screening results more reliable. Drought tolerance efficiency of genotypes was calculated based on yield, and drought-tolerant genotypes were identified with better yield efficiency and ranking on visual scale. Whereas, yield efficiency of some drought-tolerant genotypes were less, althouth they came under drought-tolerant scale. Being a tolerant genotype, these may not be economical for commercial cultivation. Under water-deficit condition a significant positive correlation was observed between drought tolerance efficiency, and RWC, Fv/Fm, CCI and root length. Out of 48 genotypes, 14 genotypes were came under highly drought-tolerant category based on 5 point scale.

scholarly journals Variability in Water Loss Patterns of New Guinea Impatiens Cultivars and Breeding Selections

1995 ◽  
Vol 120 (3) ◽  
pp. 527-531
Author(s):  
Mark S. Strefeler ◽  
Robert-Jan W. Quené
Keyword(s):  
Drought Tolerance ◽  
Water Loss ◽  
New Guinea ◽  
Drought Tolerant ◽  
Commercial Cultivars ◽  
Transpirational Water Loss ◽  
Impatiens Hawkeri ◽  
New Guinea Impatiens ◽  
Breeding Selections ◽  
Selection Of

Six commercial cultivars (Anna, Aurore, Danhill, Danlight, Melanie, and Thelca), one drought tolerant cultivar (Orangeade), nine breeding selections, and one check genotype of Impatiens hawkeri Bull were evaluated for differences in drought tolerance based on water loss and time to wilt. The six commercially available cultivars had significantly higher mean water loss than the breeding selections and `Orangeade'. These cultivars wilted in 5.11 vs. 7.33 days for `Orangeade' and 9.10 days for the breeding selections. These results suggest that sufficient variability exists in New Guinea impatiens germplasm for the reduction of water loss to improve drought tolerance. Regression analysis revealed that total transpirational water loss 96 hours after withholding water was an excellent predictor of the time to wilting (a simple measure of drought tolerance) after water was withheld (R2 = 0.95). Thus, a simple, efficient and objective method for selection of drought tolerant genotypes has been developed for New Guinea impatiens. A comparison of offspring to parental genotypes showed that after only one cycle of selection, water loss was significantly reduced by >30%. These results suggest that there is sufficient genetic variability present for the development of more drought tolerant cultivars.

scholarly journals Towards Developing Drought-smart Soybeans

2021 ◽  
Vol 12 ◽  
Author(s):  
Hina Arya ◽  
Mohan B. Singh ◽  
Prem L. Bhalla
Keyword(s):  
Crop Production ◽  
Molecular Breeding ◽  
Gene Families ◽  
Soybean Cultivars ◽  
Legume Crop ◽  
Economic Significance ◽  
New Genes ◽  
Drought Tolerant ◽  
Effects Of Drought ◽  
Or Gene

Drought is one of the significant abiotic stresses threatening crop production worldwide. Soybean is a major legume crop with immense economic significance, but its production is highly dependent on optimum rainfall or abundant irrigation. Also, in dry periods, it may require supplemental irrigation for drought-susceptible soybean varieties. The effects of drought stress on soybean including osmotic adjustments, growth morphology and yield loss have been well studied. In addition, drought-resistant soybean cultivars have been investigated for revealing the mechanisms of tolerance and survival. Advanced high-throughput technologies have yielded remarkable phenotypic and genetic information for producing drought-tolerant soybean cultivars, either through molecular breeding or transgenic approaches. Further, transcriptomics and functional genomics have led to the characterisation of new genes or gene families controlling drought response. Interestingly, genetically modified drought-smart soybeans are just beginning to be released for field applications cultivation. In this review, we focus on breeding and genetic engineering approaches that have successfully led to the development of drought-tolerant soybeans for commercial use.

scholarly journals Responses and Differences in Tolerance to Water Shortage under Climatic Dryness Conditions in Seedlings from Quercus spp. and Andalusian Q. ilex Populations

Forests ◽  
2020 ◽  
Vol 11 (6) ◽  
pp. 707
Author(s):  
Bonoso San-Eufrasio ◽  
Rosa Sánchez-Lucas ◽  
Cristina López-Hidalgo ◽  
Victor M. Guerrero-Sánchez ◽  
María Ángeles Castillejo ◽  
...  
Keyword(s):  
Population Level ◽  
Field Capacity ◽  
Water Shortage ◽  
Total Amino Acid ◽  
Leaf Water Content ◽  
Severe Drought ◽  
Drought Tolerant ◽  
Quercus Spp ◽  
Damage Symptoms ◽  
Selection Of

Analyzing differences in tolerance to drought in Quercus spp., and the characterization of these responses at the species and individual population level, are imperative for the selection of resilient elite genotypes in reforestation programs. The main objective of this work was to evaluate differences in the response and tolerance to water shortage under in five Quercus spp. and five Andalusian Q. ilex populations at the inter- and intraspecies level. Six-month-old seedlings grown in perlite were subjected to drought treatments by withholding water for 28 days under mean 37 °C temperature, 28 W m−2 solar irradiance, and 41% humidity. The use of perlite as the substrate enabled the establishment of severe drought stress with reduction in water availability from 73% (field capacity) to 28% (dryness), corresponding to matric potentials of 0 and −30 kPa. Damage symptoms, mortality rate, leaf water content, photosynthetic, and biochemical parameters (amino acids, sugars, phenolics, and pigments) were determined. At the phenotypic level, based on damage symptoms and mortality, Q. ilex behaved as the most drought tolerant species. Drought caused a significant decrease in leaf fluorescence, photosynthesis rate, and stomatal conductance in all Quercus spp. analyzed, being less pronounced in Q. ilex. There were not differences between irrigated and non-irrigated Q. ilex seedlings in the content of sugar and photosynthetic pigments, while the total amino acid and phenolic content significantly increased under drought conditions. As a response to drought, living Q. ilex seedlings adjust stomata opening and gas exchange, and keep hydrated, photosynthetically active, and metabolically competent. At the population level, based on damage symptoms, mortality, and physiological parameters, the eastern Andalusian populations were more tolerant than the western ones. These observations inform the basis for the selection of resilient genotypes to be used in breeding and reforestation programs.

scholarly journals Acoustic Vulnerability, Hydraulic Capacitance, and Xylem Anatomy Determine Drought Response of Small Grain Cereals

2021 ◽  
Vol 12 ◽  
Author(s):  
Szanne Degraeve ◽  
Niels J. F. De Baerdemaeker ◽  
Maarten Ameye ◽  
Olivier Leroux ◽  
Geert Jozej Willem Haesaert ◽  
...  
Keyword(s):  
Drought Tolerance ◽  
Acoustic Emissions ◽  
Water Shortage ◽  
Drought Response ◽  
Xylem Embolism ◽  
Continuous Increase ◽  
Hydraulic Capacitance ◽  
The One ◽  
Cereal Plants ◽  
Selection Of

Selection of high-yielding traits in cereal plants led to a continuous increase in productivity. However, less effort was made to select on adaptive traits, favorable in adverse and harsh environments. Under current climate change conditions and the knowledge that cereals are staple foods for people worldwide, it is highly important to shift focus to the selection of traits related to drought tolerance, and to evaluate new tools for efficient selection. Here, we explore the possibility to use vulnerability to drought-induced xylem embolism of wheat cultivars Excalibur and Hartog (Triticum aestivum L.), rye cultivar Duiker Max (Secale cereale L.), and triticale cultivars Dublet and US2014 (x Triticosecale Wittmack) as a proxy for their drought tolerance. Multiple techniques were combined to underpin this hypothesis. During bench-top dehydration experiments, acoustic emissions (AEs) produced by formation of air emboli were detected, and hydraulic capacitances quantified. By only looking at the AE50 values, one would classify wheat cultivar Excalibur as most tolerant and triticale cultivar Dublet as most vulnerable to drought-induced xylem embolism, though Dublet had significantly higher hydraulic capacitances, which are essential in terms of internal water storage to temporarily buffer or delay water shortage. In addition, xylem anatomical traits revealed that both cultivars have a contrasting trade-off between hydraulic safety and efficiency. This paper emphasizes the importance of including a cultivar’s hydraulic capacitance when evaluating its drought response and vulnerability to drought-induced xylem embolism, instead of relying on the AE50 as the one parameter.

scholarly journals Genetic Diversity of Rhizobia Nodulating Alfalfa in Iraq as a Source of More Efficient Drought Tolerance Strains

2016 ◽  
Vol 6 (1) ◽  
pp. 20 ◽  
Author(s):  
Rana Azeez Hameed ◽  
Nidhal Neema Hussain ◽  
Abd aljasim Muhisen Aljibouri
Keyword(s):  
Genetic Diversity ◽  
Drought Tolerance ◽  
Soil Bacteria ◽  
Sinorhizobium Meliloti ◽  
Genetic Relationships ◽  
Tolerance Analysis ◽  
Water Shortage ◽  
Drought Tolerant ◽  
Pcr Method ◽  
Polyethylene Glycol 6000

<p class="1Body"><em>Sinorhizobium meliloti </em>is a gram-negative, soil bacteria, which gain a huge importance deserved to their capability in fixing nitrogen symbiotically with an important fodder crop legume-alfalfa (<em>Medicago sativa</em>). This study aims to (i): isolate indigenous <em>Sinorhizobium meliloti</em> from different field sites in Iraq; (ii): assess the isolates tolerance to induced water shortage using polyethylene glycol-6000; (iii): evaluate genetic diversity and genetic relationships among isolates of natural population with drought tolerant abilities. Drought tolerance analysis disclose great variations between <em>Sinorhizobium</em> isolates, the highest tolerant isolates to drought were 12 from whole thirty (40%), endured from -3 up to -4 MPa(Mega pascal), at the same time the drought sensitive isolates tolerated up to -1.5 MPa, but for isolate Bs58 which tolerated up to -1 MPa. The growth decrease with the increase of drought stress. REP-PCR method was an excellent technique to distinguish between the <em>S. </em>isolates based on their tolerance to different water potential levels, the REP-PCR gave a significant band about 700bp (base pair) in size, which were present in all drought moderate and tolerant isolates, while this band was absent in all drought sensitive isolates(except one isolate). Also the ERIC-PCR method cleared the absence of two significant bands 300bp and 600bp from all drought sensitive isolates. UPGMA analysis based on rep-PCR revealed two groups branching at a similarity of 35%, first group included only one isolate Bs16, which was a drought moderate tolerant; second group contained the rest of isolates, yet the latter splits into two subgroups with 68% similarity; the first subgroup comprised all sensitive isolates with 80% similarity among them, the second subgroup included the tolerant and moderate isolates with similarity 88%.</p>

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