Molecular Genetic Improvement of Crop Drought Tolerance

A special issue of Agronomy (ISSN 2073-4395). This special issue belongs to the section "Crop Breeding and Genetics".

Deadline for manuscript submissions: closed (31 March 2022) | Viewed by 40869

Special Issue Editor

Dr. Bu-Jun Shi
E-Mail Website
Guest Editor
Univ Adelaide, Australian Ctr Plant Funct Genom, Urrbrae, SA, Australia
Interests: abiotic stress; environmental stress

Special Issue Information

Dear Colleagues,

Drought is one of the major abiotic stresses affecting crop quality and yield, and is a very challenging issue that agriculture is facing today due to increase in temperature. We have to from now on take the drought problem seriously. To improve crop drought tolerance, many new methods and approaches have been developed or adopted in recent years. These include the application of CRISPR and anti-miRNA oligonucleotide technologies in crop drought tolerance. It is expected that these new methods and approaches will contribute molecular genetic improvement of crop drought tolerance greatly.

Dr. Bu-Jun Shi
Guest Editor

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Keywords

  • drought
  • drought tolerance
  • crop
  • small RNAs
  • CRISPR
  • genetic modification

Published Papers (10 papers)

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Research

Jump to: Review

20 pages, 5395 KiB  
Article
Nitrogen Fertilizer Modulates Plant Growth, Chlorophyll Pigments and Enzymatic Activities under Different Irrigation Regimes
Agronomy 2022, 12(4), 845; https://doi.org/10.3390/agronomy12040845 - 30 Mar 2022
Cited by 21 | Viewed by 3592
Abstract
Nitrogen fertilization and irrigation patterns have been extensively studied for common maize (Zea mays L.), but there is limited published work for Zhengda 619, especially in subtropical areas. Nitrogen (N) fertilizer and irrigation play an important role in crop growth and yield [...] Read more.
Nitrogen fertilization and irrigation patterns have been extensively studied for common maize (Zea mays L.), but there is limited published work for Zhengda 619, especially in subtropical areas. Nitrogen (N) fertilizer and irrigation play an important role in crop growth and yield improvements. The study aimed to investigate the yield, growth, chlorophyll content, reactive oxygen species (ROS) and enzyme activities of hybrid maize (Zhengda 619) under greenhouse conditions. Individual plants grown in plastic pots were subjected to two irrigation types—low irrigation (LW; 60% field capacity) and high irrigation water (HW; 80% field capacity)—and five N rates. Our results demonstrate that the LW irrigation increased dry matter, kernel yield, leaf chlorophyll, total root length, root diameter, root volume, and root surface area, as well as soil enzymes and plant antioxidant enzymes, while it lowered malondialdehyde (MDA), proline, and ROS. Moreover, most of the above parameters increased with increasing N application rates up to N3 under LW irrigation due to the increased N availability to the plant and soil enzymes. It is concluded that increasing N rates could improve soil enzyme activities as well as plant antioxidant enzymes and decrease ROS, ultimately resulting in a higher kernel yield under LW irrigation. Full article
(This article belongs to the Special Issue Molecular Genetic Improvement of Crop Drought Tolerance)
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16 pages, 2551 KiB  
Article
Chitosan-Induced Physiological and Biochemical Regulations Confer Drought Tolerance in Pot Marigold (Calendula officinalis L.)
Agronomy 2022, 12(2), 474; https://doi.org/10.3390/agronomy12020474 - 14 Feb 2022
Cited by 27 | Viewed by 2727
Abstract
Severe water stress conditions limit growth and development of floricultural crops which affects flower quality. Hence, development of effective approaches for drought tolerance is crucial to limit recurring water deficit challenges. Foliar application of various plant growth regulators has been evaluated to improve [...] Read more.
Severe water stress conditions limit growth and development of floricultural crops which affects flower quality. Hence, development of effective approaches for drought tolerance is crucial to limit recurring water deficit challenges. Foliar application of various plant growth regulators has been evaluated to improve drought tolerance in different floricultural crops; however, reports regarding the role of chitosan (Ci) on seasonal flowers like calendula are still scant. Therefore, we evaluated the role of Ci foliar application on morphological, physiological, biochemical, and anatomical parameters of calendula under water stress conditions. Different doses of Ci (0, 2.5, 5, 7.5, 10 mg L−1) were applied through foliar application to evaluate their impact in enhancing growth and photosynthetic pigments of calendula. The optimized Ci level of 7.5 mg L−1 was further evaluated to study mechanisms of water stress tolerance in calendula. Ci application significantly increased biomass and pigments in calendula. Ci (7.5 mg L−1) resulted in increased photosynthetic rate (72.98%), transpiration rate (62.11%), stomatal conductance (59.54%), sub-stomatal conductance (20.62%), and water use efficiency (84.93%). Furthermore, it improved catalase, guaiacol peroxidase, and superoxide dismutase by 56.70%, 64.94%, and 32.41%, respectively. These results highlighted the significance of Ci in inducing drought tolerance in pot marigold. Full article
(This article belongs to the Special Issue Molecular Genetic Improvement of Crop Drought Tolerance)
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17 pages, 912 KiB  
Article
Screening of Wheat (Triticum aestivum L.) Genotypes for Drought Tolerance through Agronomic and Physiological Response
Agronomy 2022, 12(2), 287; https://doi.org/10.3390/agronomy12020287 - 23 Jan 2022
Cited by 51 | Viewed by 7193
Abstract
Water scarcity is a major challenge to wheat productivity under changing climate conditions, especially in arid and semi-arid regions. During recent years, different agronomic, physiological and molecular approaches have been used to overcome the problems related to drought stress. Breeding approaches, including conventional [...] Read more.
Water scarcity is a major challenge to wheat productivity under changing climate conditions, especially in arid and semi-arid regions. During recent years, different agronomic, physiological and molecular approaches have been used to overcome the problems related to drought stress. Breeding approaches, including conventional and modern breeding, are among the most efficient options to overcome drought stress through the development of new varieties adapted to drought. Growing drought-tolerant wheat genotypes may be a sustainable option to boost wheat productivity under drought stress conditions. Therefore, the present study was conducted with the aim to screen different wheat genotypes based on stress tolerance levels. For this purpose, eleven commonly cultivated wheat genotypes (V1 = Akbar-2019, V2 = Ghazi-2019, V3 = Ujala-2016, V4 = Zincol-2016, V5 = Anaj-2017, V6 = Galaxy-2013, V7 = Pakistan-2013, V8 = Seher-2006, V9 = Lasani-2008, V10 = Faisalabad-2008 and V11 = Millat-2011) were grown in pots filled with soil under well-watered (WW, 70% of field capacity) and water stress (WS, 35% of field capacity) conditions. Treatments were arranged under a completely randomized design (CRD) with three replicates. Data on yield and yield-related traits (tillers/plant, spikelets/spike, grains/spike, 100 grain weight, seed and biological yield) and physio-biochemical (chlorophyll contents, relative water content, membrane stability index, leaf nitrogen, phosphorus, and potassium content) attributes were recorded in this experiment. Our results showed that drought stress significantly affected the morpho-physiological, and biochemical attributes in all tested wheat varieties. Among the genotypes, all traits were found to be significantly (p < 0.05) higher in wheat genotype Faisalabad-2008, including biological yield (9.50 g plant−1) and seed yield (3.39 g plant−1), which was also proven to be more drought tolerant than the other tested genotypes. The higher biological and grain yield of genotype Faisalabad-2008 was mainly attributed to greater numbers of tillers/plant and spikelets/spike compared to the other tested genotypes. The wheat genotype Galaxy-2013 had significantly lower biological (7.43 g plant−1) and seed yield (2.11 g plant−1) than all other tested genotypes, and was classified as a drought-sensitive genotype. For the genotypes, under drought stress, biological and grain yield decreased in the order V10 > V2 > V1 > V4 > V7 > V11 > V9 > V8 > V3 > V6. These results suggest that screening for drought-tolerant genotypes may be a more viable option to minimize drought-induced effects on wheat in drought-prone regions. Full article
(This article belongs to the Special Issue Molecular Genetic Improvement of Crop Drought Tolerance)
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18 pages, 7571 KiB  
Article
On the Use of Sap Flow Measurements to Assess the Water Requirements of Three Australian Native Tree Species
Agronomy 2022, 12(1), 52; https://doi.org/10.3390/agronomy12010052 - 27 Dec 2021
Cited by 9 | Viewed by 3187
Abstract
The measurement of sap movement in xylem sapwood tissue using heat pulse velocity sap flow instruments has been commonly used to estimate plant transpiration. In this study, sap flow sensors (SFM1) based on the heat ratio method (HRM) were used to assess the [...] Read more.
The measurement of sap movement in xylem sapwood tissue using heat pulse velocity sap flow instruments has been commonly used to estimate plant transpiration. In this study, sap flow sensors (SFM1) based on the heat ratio method (HRM) were used to assess the sap flow performance of three different tree species located in the eastern suburbs of Melbourne, Australia over a 12-month period. A soil moisture budget profile featuring potential evapotranspiration and precipitation was developed to indicate soil moisture balance while the soil-plant-atmosphere continuum was examined at the study site using data obtained from different monitoring instruments. The comparison of sap flow volume for the three species clearly showed that the water demand of Corymbia maculata was the highest when compared to Melaleuca styphelioides and Lophostemon confertus and the daily sap flow volume on the north side of the tree on average was 63% greater than that of the south side. By analysing the optimal temperature and vapour pressure deficit (VPD) for transpiration for all sampled trees, it was concluded that the Melaleuca styphelioides could better cope with hotter and drier weather conditions. Full article
(This article belongs to the Special Issue Molecular Genetic Improvement of Crop Drought Tolerance)
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16 pages, 3772 KiB  
Article
Plant-Derived Smoke Ameliorates Salt Stress in Wheat by Enhancing Expressions of Stress-Responsive Genes and Antioxidant Enzymatic Activity
Agronomy 2022, 12(1), 28; https://doi.org/10.3390/agronomy12010028 - 24 Dec 2021
Cited by 9 | Viewed by 3043
Abstract
Abiotic stresses are the biggest threat to the increasing population worldwide. Salt stress is one of the most significant abiotic stresses, affecting 20% of the crop production around the world. Plant-derived smoke (PDS) has been reported as a biologically active plant product in [...] Read more.
Abiotic stresses are the biggest threat to the increasing population worldwide. Salt stress is one of the most significant abiotic stresses, affecting 20% of the crop production around the world. Plant-derived smoke (PDS) has been reported as a biologically active plant product in stimulating seed germination, seedling growth and physiological characteristics of crops under abiotic stress conditions. Nevertheless, studies showing how PDS alleviates salt stress are largely unknown. Here, we report the molecular mechanism of how PDS could alleviate salt stress in wheat. Initially, PDS at 2000 ppm enhanced seed germination, root/shoot length and seedling fresh weight. However, PDS at 1000 and 500 ppm did not show any significant effect. Salt stress at 150 and 200 mM significantly reduced seed germination rate, root/shoot length and fresh weight of the wheat seedlings. Interestingly, PDS supplementation at 2000 ppm concentration was sufficient to restore seed germination under salt stress condition. Moreover, PDS improved root/shoot length and seedling biomass under 150 and 200 mM salt stress, suggesting that PDS is a potent plant product, capable of abiotic stress alleviation in crops. In comparison to the control, PDS-treated seedlings displayed increased activity of major antioxidative enzymes such as superoxide dismutase, peroxidase and ascorbate peroxidase under salt stress, resulting in reduced levels of hydrogen peroxide and lipid peroxidase, showing that PDS can possibly help in salt stress amelioration by regulating redox homeostasis. Importantly, salt stress altered the expression of germination marker genes, such as TaSAM, TaPHY, TaBGU (germination positive effectors), TaLEA and TaGARS34 (germination negative effectors), suggesting the potential role of PDS in the germination pathway under salt stress. Further, PDS modulated the transcript levels of several salt stress stress-responsive genes, including TaSOS4, TaBADH and TaHKT2. In conclusion, this study provides a molecular and physiological basis for elucidating the mechanism of how PDS functions in stress induction in wheat, as well as demonstrates the importance of PDS in agricultural practices, laying the groundwork for future research into the role of PDS in the amelioration of abiotic stresses in various plants. Full article
(This article belongs to the Special Issue Molecular Genetic Improvement of Crop Drought Tolerance)
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14 pages, 3671 KiB  
Article
Potassium-Induced Drought Tolerance of Potato by Improving Morpho-Physiological and Biochemical Attributes
Agronomy 2021, 11(12), 2573; https://doi.org/10.3390/agronomy11122573 - 17 Dec 2021
Cited by 13 | Viewed by 2977
Abstract
Potato (Solanum tuberosum) is the third and fourth most important tuberous crop in terms of human consumption and production, respectively. However, its growth and development are affected by drought, which is an emerging threat to agriculture especially in arid and semiarid [...] Read more.
Potato (Solanum tuberosum) is the third and fourth most important tuberous crop in terms of human consumption and production, respectively. However, its growth and development are affected by drought, which is an emerging threat to agriculture especially in arid and semiarid areas. Potassium (K) is a well-known macronutrient that improves the performance of crops under drought. Therefore, the present study was enacted with the aim of evaluating the impact of K fertilizer on potato crop growth, productivity, and drought tolerance under full root irrigation (FRI) and partial root irrigation (PRI) conditions. Two potato cultivars (Lady Rosetta and Hermes) were grown under normal field conditions followed by FRI and PRI applications. Potassium sulfate was applied in three doses (T0 = 50 kg·ha−1, T1 = 75 kg·ha−1, and T2 = 100 kg·ha−1). The experiment was laid out under randomized complete block design (RCBD) with split plot arrangement. The main plot was allocated to irrigation, along with a subplot to potassium and a sub-subplot to potato cultivars. The results indicated that K application significantly improved the plant growth and yield by exhibiting better performance in morpho-physiological and biochemical attributes under FRI and PRI conditions; however, a more remarkable change was noticed under PRI compared with FRI. K application alleviated drought stress regardless of cultivars. This study suggests that K application at the rate of 100 kg·ha−1 is an effective approach for inducing drought tolerance in potato crops. Full article
(This article belongs to the Special Issue Molecular Genetic Improvement of Crop Drought Tolerance)
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17 pages, 3020 KiB  
Article
Yield Stability and Genotype Environment Interaction of Water Deficit Stress Tolerant Mung Bean (Vigna radiata L. Wilczak) Genotypes of Bangladesh
Agronomy 2021, 11(11), 2136; https://doi.org/10.3390/agronomy11112136 - 25 Oct 2021
Cited by 11 | Viewed by 2298
Abstract
Water deficit stress is a critical abiotic constraint to mung bean production that affects plant growth and development and finally reduces crop yield. Therefore, a field experiment was conducted at five diverse environments using four water stress-tolerant genotypes, namely BARI Mung-8, BMX-08010-2, BMX-010015, [...] Read more.
Water deficit stress is a critical abiotic constraint to mung bean production that affects plant growth and development and finally reduces crop yield. Therefore, a field experiment was conducted at five diverse environments using four water stress-tolerant genotypes, namely BARI Mung-8, BMX-08010-2, BMX-010015, and BMX-08009-7, along with two popular cultivated varieties (check) of BARI Mung-6 and BARI Mung-7 to evaluate more stable tolerant genotypes across the country. Stability analysis was performed based on the grain yield. The combined analysis of variance showed significant variations among genotypes, environments, and their interactions. The AMMI analysis of variance indicated that genotype accounted for 91% of the total sum of squares for grain yield, followed by genotype × environment interaction (5%), and environment (4%). Partitioning of interaction indicated that the first three interaction principal components (IPCA1–IPCA3) were highly significant (p ≤ 0.01). Using these significant IPCAs, AMMI stability parameters and non-parameter indices BMX-010015 was found stable across the environment based on yield traits and grain yield. The BMX-08010-2 genotype also showed significant regression coefficient (bi) more than unity, and non-significant deviation from regression (S2di) values, indicating suitable for a favorable environment considering grain yield. So, based on the stability analysis (Eberhart and Russell), additive main effects, and multiplicative interactions (AMMI) analysis, the BMX-010015 and BMX-08010-2 could be suitable for having tolerance to water deficit stress. Full article
(This article belongs to the Special Issue Molecular Genetic Improvement of Crop Drought Tolerance)
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16 pages, 775 KiB  
Article
Effect of Water Stress on Grain Yield and Physiological Characters of Quinoa Genotypes
Agronomy 2021, 11(10), 1934; https://doi.org/10.3390/agronomy11101934 - 27 Sep 2021
Cited by 22 | Viewed by 3802
Abstract
Climate change scenarios predict that an extended period of drought is a real threat to food security, emphasizing the need for new crops that tolerate these conditions. Quinoa is the best option because it has the potential to grow under water deficit conditions. [...] Read more.
Climate change scenarios predict that an extended period of drought is a real threat to food security, emphasizing the need for new crops that tolerate these conditions. Quinoa is the best option because it has the potential to grow under water deficit conditions. There is considerable variation in drought tolerance in quinoa genotypes, and the selection of drought-tolerant quinoa germplasms is of great interest. The main goal of this work is to evaluate the crop yield and characterize the physiology of 20 quinoa genotypes grown under water deficit in a wirehouse. The experiment was a complete randomized design (CRD) factorial with three replications. Seedling growth, i.e., fresh weight (FW), dry weight (DW), root length (RL), shoot length (SL), relative growth rate of root length (RGR-RL), shoot length (RGR-SL), and physiological performance, i.e., chlorophyll content (a and b), carotenoid, leaf phenolic content, leaf proline content, membrane stability index (MSI), and leaf K+ accumulation were evaluated in a hydroponic culture under different water-deficit levels developed by PEG 6000 doses (w/v) of 0% (control), 0.3%, and 0.6%. Yield attributes were evaluated in a pot at three different soil moisture levels, as determined by soil gravimetric water holding capacity (WHC) of 100 (control), 50% WHC (50 % drought stress) and 25% WHC (75% stress). In both experiments, under the water stress condition, the growth (hydroponic study) and yield traits (pot study) were significantly reduced compared to control treatments. On the drought tolerance index (DTI) based on seed yield, genotype 16 followed by 10, 1, 4, 5, 7, and 12 could be considered drought-tolerant genotypes that produced maximum grain yield and improved physiological characteristics under severe water stress conditions in hydroponic culture. In both studies, genotypes 3, 8, 13, and 20 performed poorly and were considered drought-sensitive genotypes with the lowest DTI values under water-stressed conditions. All the studied agronomic traits (grain yield, root and shoot length, shoot fresh and dry weights) and physiological traits (leaf phenolic, proline content, carotenoid, K+ accumulation, membrane stability index, and relative water content) were firmly inter-correlated and strongly correlated with DTI. They can be regarded as screening criteria, employing a large set of quinoa genotypes in a breeding program. Full article
(This article belongs to the Special Issue Molecular Genetic Improvement of Crop Drought Tolerance)
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20 pages, 484 KiB  
Article
Evaluation of Drought Tolerance of Some Wheat (Triticum aestivum L.) Genotypes through Phenology, Growth, and Physiological Indices
Agronomy 2021, 11(9), 1792; https://doi.org/10.3390/agronomy11091792 - 07 Sep 2021
Cited by 51 | Viewed by 7009
Abstract
Increasing human population and changing climate, which have given rise to frequent drought spells, pose a serious threat to global food security, while identification of high yielding drought tolerant genotypes remains a proficient approach to cope with these challenges. To offer a methodology [...] Read more.
Increasing human population and changing climate, which have given rise to frequent drought spells, pose a serious threat to global food security, while identification of high yielding drought tolerant genotypes remains a proficient approach to cope with these challenges. To offer a methodology for the evaluation of the drought-tolerant wheat genotypes based on the pheno-physiological traits, a field experiment was executed, entailing four wheat genotypes viz. BARI Gom 26, BAW 1158, BAW 1167, and BAW 1169 and two water conditions viz. control treatment (three times irrigation at 20, 50, and 70 DAS, i.e., 100% field capacity) and stressed treatment (no irrigation during the entire growing season). The results revealed that drought stress drastically reduced the days to booting, heading, anthesis and physiological maturity, relative water content (RWC), chlorophyll content, canopy temperature depression (CTD), and photo-assimilates-spike dry matter (SDM), grains spike−1 and grain yield of all wheat genotypes. In addition, the genotypes BAW 1167 and BARI Gom 26 remained more prone to adverse effects of drought as compared to BAW 1169 and BAW 1158. Furthermore, DS induced biosynthesis of compatible solutes such as proline, especially in BAW 1169, which enabled plants to defend against oxidative stress. It was inferred that BAW 1169 remained superior by exhibiting the best adaptation as indicated by the maximum relative values of RWC, total chlorophyll, CTD, proline content, SDM, grains spike−1, and grain yield of wheat. Thus, based on our findings, BAW 1169 may be recommended for general adoption and utilization in future wheat breeding programs aimed at developing potent drought-tolerant wheat genotypes to ensure food security on a sustainable basis. Full article
(This article belongs to the Special Issue Molecular Genetic Improvement of Crop Drought Tolerance)
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Review

Jump to: Research

24 pages, 1935 KiB  
Review
The Genetic Control of Stomatal Development in Barley: New Solutions for Enhanced Water-Use Efficiency in Drought-Prone Environments
Agronomy 2021, 11(8), 1670; https://doi.org/10.3390/agronomy11081670 - 22 Aug 2021
Cited by 1 | Viewed by 3561
Abstract
Increased drought frequency due to climate change is limiting the agronomic performance of cereal crops globally, where cultivars often experience negative impacts on yield. Stomata are the living interface responsible for >90% of plant water loss through transpiration. Thus, stomata are a prospective [...] Read more.
Increased drought frequency due to climate change is limiting the agronomic performance of cereal crops globally, where cultivars often experience negative impacts on yield. Stomata are the living interface responsible for >90% of plant water loss through transpiration. Thus, stomata are a prospective target for improving drought tolerance by enhancing water-use efficiency (WUE) in economically important cereals. Reducing stomatal density through molecular approaches has been shown to improve WUE in many plant species, including the commercial cereals barley, rice, wheat and maize. Rice with reduced stomatal density exhibit yields 27% higher than controls under drought conditions, reflecting the amenability of grasses to stomatal density modification. This review presents a comprehensive overview of stomatal development, with a specific emphasis on the genetic improvement of WUE in the grass lineage. Improved understanding of the genetic regulation of stomatal development in the grasses, provides significant promise to improve cereal adaptivity in drought-prone environments whilst maximising yield potential. Rapid advances in gene-editing and ‘omics’ technologies may allow for accelerated adaption of future commercial varieties to water restriction. This may be achieved through a combination of genomic sequencing data and CRISPR-Cas9-directed genetic modification approaches. Full article
(This article belongs to the Special Issue Molecular Genetic Improvement of Crop Drought Tolerance)
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