Drought Tolerant Wheat Varieties Research Articles

UAV remote sensing phenotyping of wheat collection for response to water stress and yield prediction using machine learning

Water stress is a significant challenge for global food production. Rainfall pattern is becoming unpredictable due to climate change that causes unprecedent water stress conditions in cereals production including wheat which is one of the important staple food crops. To sustain wheat production under water limiting conditions, there is an urgent need to develop drought-tolerant wheat varieties. For this, screening large numbers of wheat genotype for traits related to growth and yield under water stressed conditions is crucial. In this study, we deployed high-throughput phenotyping approaches, including uncrewed aerial vehicle (UAV)-based multispectral imaging, advanced machine and deep learning regression models. Two separate field experiments, irrigated and rainfed, were conducted comprising 553 wheat genotypes, and collected dataset for traits such as plant height, phenology, grain yield, and timeseries multispectral imaging. UAV-multispectral imagery derived plant height measurements showed a high correlation (R2=0.75) with manual measurements. Vegetation indices derived from multispectral data differentiated growth pattern of genotypes under rainfed and irrigated conditions and were used in yield prediction modeling. Wheat genotypes were effectively ranked, and their response differentiated for water stress tolerance based on yield index, stress susceptibility index, and yield loss%. Importantly, yield prediction in genotypes was computed using four machine learning regression algorithms i.e., linear regression, support vector machine, random forest, and deep learning H2O-3, where H2O-3 was the most accurate model with R2=0.80. Results show that multispectral-driven traits combined with machine learning models effectively phenotyped large wheat population and such approaches can be integrated in crop breeding program to develop varieties tolerant to water stress.

Screening for drought tolerance and genetic diversity of wheat varieties using agronomic and molecular markers.

The future predictions for frequent and severe droughts will represent a significant threat to wheat yield and food security. In this context, breeding has proven to be the most efficient approach to enhance wheat productivity in dry environments. In this study, both agronomic and molecular-based approaches were used to evaluate the response of twenty-eight Tunisian wheat varieties to drought stress. The primary objective was to screen these varieties for drought tolerance using molecular and agro-morphological markers. All varieties were significantly affected by drought stress regarding various traits including total dry matter, straw length, flag leaf area, number of senescent leaves, SPAD value, grain yield and grain number. Furthermore, substantial variability in drought-stress tolerance was observed among wheat genotypes. The cluster analysis and principal component analyses confirmed the existence of genotypic variation in growth and yield impairments induced by drought. The stress susceptibility index (SSI) and tolerance index (TOL) proved to be the most effective indices and were strongly correlated with the varying levels of genotypic tolerance. The genotyping evaluation resulted in the amplification of 101 alleles using highly polymorphic 12 SSR markers, showed an average polymorphism of 74%. Taken together, the combination of agronomic and molecular approaches revealed that Karim, Td7, D117 and Utique are the most drought-tolerant wheat varieties. These varieties are particularly promising candidates for genetic improvements and can be utilized as potential genitors for future breeding programs in arid and semi-arid regions.

Drought responsiveness in six wheat genotypes: identification of stress resistance indicators.

Wheat (Triticum aestivum L.) is among the world's most important staple food crops. In the current climate change scenario, a better understanding of wheat response mechanisms to water stress could help to enhance its productivity in arid ecosystems. In this study, water relations, gas exchange, membrane integrity, agronomic traits and molecular analysis were evaluated in six wheat genotypes (D117, Syndiouk, Tunisian durum7 (Td7), Utique, Mahmoudi AG3 and BT) subjected to drought-stress. For all the studied genotypes, drought stress altered leaf area, chlorophyll content, stomatal density, photosynthetic rate and water-use efficiency, while the relative water content at turgor loss point (RWC0) remained stable. Changes in osmotic potential at turgor loss point (Ψπ0), bulk modulus of elasticity (Ɛmax) and stomatal regulation, differed greatly among the studied genotypes. For the drought-sensitive genotypes AG3 and BT, no significant changes were observed in Ψπ0, whereas the stomatal conductance (gs) and transpiration rate (E) decreased under stress conditions. These two varieties avoided turgor loss during drought treatment through an accurate stomatal control, resulting in a significant reduction in yield components. On the contrary, for Syndiouk, D117, Td7 and Utique genotypes, a solute accumulation and an increase in cell wall rigidity were the main mechanisms developed during drought stress. These mechanisms were efficient in enhancing soil water uptake, limiting leaf water loss and protecting cells membranes against leakage induced by oxidative damages. Furthermore, leaf soluble sugars accumulation was the major component of osmotic adjustment in drought-stressed wheat plants. The transcriptional analysis of genes involved in the final step of the ABA biosynthesis (AAO) and in the synthesis of an aquaporin (PIP2:1) revealed distinct responses to drought stress among the selected genotypes. In the resistant genotypes, PIP2:1 was significantly upregulated whereas in the sensitive ones, its expression showed only a slight induction. Conversely, the sensitive genotypes exhibited higher levels of AAO gene expression compared to the resistant genotypes. Our results suggest that drought tolerance in wheat is regulated by the interaction between the dynamics of leaf water status and stomatal behavior. Based on our findings, Syndiouk, D117, Utique and Td7, could be used in breeding programs for developing high-yielding and drought-tolerant wheat varieties.

Drought tolerance assessment and trait associations in two wheat accessions under varying water stress conditions

This study aimed to assess drought tolerance in two wheat accessions (ATTILA-7 and RYENA 28) under different water stress conditions and examine trait associations. The accessions were subjected to well-watered, moderately watered, and drought-stressed treatments. Various yield and yield-determining traits were measured, including plant height, number of tillers, days to heading, spikelets per spike, seeds per plant, and grain yield. Significant differences were observed among accessions and treatments for most traits. RYENA-28 (AC2) performed better under drought stress. Correlation analysis revealed consistent negative correlations between the number of days to heading and the number of seeds per plant across treatments (-0.93, -0.89, and -0.93), while the number of seeds per plant consistently showed significantly positive correlations with grain yield per plant (0.96, 0.97, and 0.82) across treatments. Plant height exhibited negative correlations with the number of tillers and days to heading but positive correlations with grain yield. Notably, the number of spikelets per spike consistently correlated positively with the number of seeds per plant across treatments. These findings provide insights for breeding programs focused on drought tolerance in wheat, emphasizing the selection of accessions with shorter stature, increased spikelets, and higher seed production to develop drought-tolerant wheat varieties with improved yield potential.

Comparative Study of Wheat (Triticum aestivum L.) Genotypes in Irrigated and Rainfed Conditions

Wheat is 3rd major cereal crop of Nepal in terms of production and productivity, however, in a significant area wheat is still grown under rainfed conditions. There are very less wheat varieties particularly released for rainfed environments, indicating a very poor varietal choice for the farmers. This study aims to compare the performance of selected wheat genotypes under irrigated and rainfed conditions of the western terai region of Nepal to identify suitable genotypes for low moisture stress conditions. The experiment was conducted comprising 24 wheat genotypes including check varieties (Gautam, RR21, and Bhrikuti) in Alpha Lattice design with two replications at the Directorate of Agricultural Research, Lumbini Province, Khajura, Banke in 2021/22. The set of genotypes was evaluated simultaneously under rainfed and irrigated environments in an open field condition. In a rainfed environment, NL 1446 produced the maximum grain yield of 3488 kg ha-1, followed by NL 1437 (3357 kg ha-1). The highest grain yield under irrigation was obtained from NL 1503, which produced 4273 kg ha-1, followed by NL 1437 (4242 kg ha-1). Regarding grain yield, NL 1437 was observed to be a better genotype under both circumstances. NL 1437 produced an average grain yield of 3799 kg ha-1 after integrated analysis. According to the study, NL 1503 is the best genotype to be used, provided timely irrigation is guaranteed; otherwise, NL 1446 and NL 1437 are the best alternatives. NL 1437 gave the highest mean grain yield in both rainfed and irrigated conditions, thus having greater potential for cultivation in water-stress environments. Likewise, the results from the study can be helpful in breeding programs and facilitate the development of drought-tolerant wheat varieties.

Genetic Effects of GA-Responsive Dwarfing Gene Rht13 on Plant Height, Peduncle Length, Internodal Length and Grain Yield of Wheat under Drought Stress.

Reduction in plant height is generally associated with an increase in lodging resistance, drought tolerance and grain yield of wheat worldwide. Historically, a significant increase in grain yield was observed through the introduction of semi-dwarf wheat varieties utilizing the gibberellic acid-insensitive Rht genes (Rht1 or Rht2). The gibberellic acid sensitive (GA-sensitive) reduced height (Rht) genes are available that are alternatives to gibberellic acid insensitive (GA-insensitive) Rht genes, having a neutral effect on coleoptile length seedling vigor suggesting their potential in using alone or in combination with GA-insensitive Rht genes to improve grain yield and drought tolerance in wheat. This study was conducted to evaluate parents and F1 crosses under drought stress. The crossing was done using line × tester mating design, comprising eight lines and five testers having different GA-sensitive and GA-insensitive Rht genes. Parents and F1 crosses were sown in the field under RCBD with three replications in normal and drought stress. Data were recorded for morpho-physiological traits. The mean comparison showed significant differences among parents and hybrids for most of the studies' traits. The general combining ability showed that line 1 is the good general combiner for days to heading, lodging (%), plant height, peduncle length, internodal length and days to maturity under normal conditions while L5 was the good general cobiner for chlorophyll contents and stomatal conductance both under normal and drought stress. The spcaicfic combing ability estimases showed that the cross L1 × T1 was best for days to heading, lodging (%), plant height and internodal length both under normal and drought stress. F1 hybrids showed a significant reduction in plant height (18-25%), peduncle length (20-28%) and increased grain yield (15-18%) under drought stress. Expression analysis showed upregulation of Rht13 at the middle part of the peduncle internode under drought stress. From the expression analysis, five crosses were selected, and their segregating population was raised and space-plated. Rht13 genes reduced plant height (-30 to -45%), peduncle length (-30 to -53%), peduncle internode length (-28% to -48%), increased spike length (+20% to +50%), number of grains per spike (+17 to +26%) and grain yield per plant (+29% to +50%) compared to Rht1 gene. These results suggested the possibility of using the GA-sensitive Rht13 gene for the development of high-yielding and drought-tolerant wheat varieties.

TaERF87 and TaAKS1 synergistically regulate TaP5CS1/TaP5CR1-mediated proline biosynthesis to enhance drought tolerance in wheat.

Drought stress limits wheat production and threatens food security world-wide. While ethylene-responsive factors (ERFs) are known to regulate plant response to drought stress, the regulatory mechanisms responsible for a tolerant phenotype remain unclear. Here, we describe the positive regulatory role of TaERF87 in mediating wheat tolerance to drought stress. TaERF87 overexpression (OE) enhances drought tolerance, while silencing leads to drought sensitivity in wheat. RNA sequencing with biochemical assays revealed that TaERF87 activates the expression of the proline biosynthesis genes TaP5CS1 and TaP5CR1 via direct binding to GCC-box elements. Furthermore, proline accumulates to higher levels in TaERF87- and TaP5CS1-OE lines than that in wild-type plants under well-watered and drought stress conditions concomitantly with enhanced drought tolerance in these transgenic lines. Moreover, the interaction between TaERF87 and the bHLH transcription factor TaAKS1 synergistically enhances TaP5CS1 and TaP5CR1 transcriptional activation. TaAKS1 OE also increases wheat drought tolerance by promoting proline accumulation. Additionally, our findings verified that TaERF87 and TaAKS1 are targets of abscisic acid-responsive element binding factor 2 (TaABF2). Together, our study elucidates the mechanisms underlying a positive response to drought stress mediated by the TaABF2-TaERF87/TaAKS1-TaP5CS1/TaP5CR1 module, and identifies candidate genes for the development of elite drought-tolerant wheat varieties.

Genetic Dissection of Drought Tolerance of Elite Bread Wheat (Triticum aestivum L.) Genotypes Using Genome Wide Association Study in Morocco.

Drought is one of the most important yield-limiting factors in Morocco. Identification and deployment of drought-tolerant wheat varieties are important to cope with the challenge of terminal moisture stress and increase wheat productivity. A panel composed of 200 elite spring bread wheat genotypes was phenotyped for yield and agronomic traits for 2 years (2020 and 2021) in Morocco under rainfed and irrigated environments. The panel was genotyped using 20K SNPs and, after filtration, a total of 15,735 SNP markers were used for a genome-wide association study (GWAS) using a mixed linear model (MLM) to identify marker-trait associations (MTA) and putative genes associated with grain yield and yield-related traits under rainfed and irrigated conditions. Significant differences were observed among the elite genotypes for grain yield and yield-related traits. Grain yield performance ranged from 0.97 to 6.16 t/ha under rainfed conditions at Sidi Al-Aidi station and from 3.31 to 9.38 t/h under irrigated conditions at Sidi Al-Aidi station, while Grain yield at Merchouch station ranged from 2.32 to 6.16 t/h under rainfed condition. A total of 159 MTAs (p < 0.001) and 46 genes were discovered, with 67 MTAs recorded under rainfed conditions and 37 MTAs recorded under irrigated conditions at the Sidi Al-Aidi station, while 55 MTAs were recorded under rainfed conditions at Merchouch station. The marker ‘BobWhite_c2988_493’ on chromosome 2B was significantly correlated with grain yield under rainfed conditions. Under irrigated conditions, the marker ‘AX-94653560’ on chromosome 2D was significantly correlated with grain yield at Sidi Al-Aidi station. The maker ‘RAC875_c17918_321’ located on chromosome 4A, associated with grain yield was linked with the gene TraesCS4A02G322700, which encodes for F-box domain-containing protein. The markers and candidate genes discovered in this study should be further validated for their potential use in marker-assisted selection to generate high-yielding wheat genotypes with drought tolerance.

Elucidating the Drought Responsiveness in Wheat Genotypes

Drought is one of the major abiotic constraints on wheat yields and also for sustainability of production levels around the world. In the near future, the occurrence likelihood of droughts is predicted to become more common, due to changing climatic conditions, thereby posing a serious threat to the food security system. Heterogeneity, in its time of occurrence and severity levels, is likely to further augment the complexity of drought conditions. Although wheat crop growth has progressively risen to good levels, as evident by notable increases in both area and production, the expected wheat demand for the ever-growing population is quite high. Besides crop yield volatility in the era of climate change and dwindling resources, “trait-based” breeding programs are required, so as to develop high yielding, climate resilient and stable genotypes, at a faster pace. For this to happen, a broad genetic base and wider adaptability to suit varied agro-ecologies would provide enough scope for their quicker spread. The current review places emphasis on making distinct categories of the wheat cultivars/advanced breeding lines, as tolerant, moderately tolerant or susceptible to drought stresses, duly supported by an extensive up-to-date literature base and will be useful for wheat researchers, in order to choose the best potential donors as parents, coupled with the associated traits for the development of drought-tolerant wheat varieties, and also to facilitate molecular studies.

Effect of Drought Stress on Fertile Tillers of Wheat Genotypes (Triticum aestivum L.)

Wheat is staple food in many countries and a key cereal crop of the world. In Asia and south Asian areas wheat is the second leading cereal crop and it is providing 68% of energy. It provides trace elements, carbohydrates and protein to our body. Drought stress is a major problem and threating crop productivity around the world. It affects wheat crop at all growth stages and reduces its yield potential from 10-90%. So, there is dire need to develop drought tolerant wheat varieties. This study was conducted by using ten high yielding varieties of wheat. These varieties were sown under normal conditions and drought stress under randomized complete block design with three replications. The data was collected for plant height, number of productive tillers per plant, spike length, peduncle length, number of spikelets per spike, number of grains per spike, yield per spike, yield per plant, 1000-grain weight. Analysis of variance was executed and results were analyzed. The results showed that all characters were showing highly significant results for irrigation and genotypes except spike length. Interaction of irrigation and genotypes showed non-significant results for grains per spike, grain yield per spike, yield per plant and 1000-grain weight but show significant for spikelets per spike and highly significant for plant height number of tillers per plant and peduncle length. The graphical representation of genotypes under normal condition and drought stress was done by mean values. Inqlab-91 performed good for grain yield, yield per plant and 1000-grain weight under both levels of irrigation followed by Galaxy-13. Genotypes C-273 and C-250 were tallest under normal irrigation. Thus, results obtained from this research will be useful in selecting best genotypes for rainfed and water stress environment in future breeding programs.

Влияние засухи на морфофизиологические показатели и показатели продуктивности изученных местных генотипов пшеницы

Drought stress is the most important factor and an increasingly serious problem limiting the growth of wheat (Triticum aestivum L. / Triticum durum) in the world. Wheat possesses physiological mechanisms that allow it to adapt to the stress of drought and can vary depending on the genotype. The studies were carried out on wheat genotypes at the Absheron Experimental Base Station of the Azerbaijan Scientific Research Institute of Crop Husbandry. The experiment was designed in a factorial design with two treatments (irrigated and non-irrigated) and three repetitions during the 2020–2021 harvest season. Analysis of variance revealed significant differences between treatments and between varieties. The treatment × cultivar interaction was also significant for all traits, with the exception of grain per plant yield. Significant interactions showed that varieties performed differently under stressful conditions, but consistently with respect to grain yield. The studied varieties Giymatly-2/17, Gunashly and Tale-38 showed a minimal decrease in physiological characteristics, as well as in yield characteristics under stress during flowering, however, a decrease from low to high was observed under stress conditions compared with no stress. Correlations between morphological, physiological, and morphophysiological traits such as plant height, number of grains per ear, seed index, grain yield per plant, yield index, relative water content, stomatal conductance, leaf area and ear fertility have generally been reliable indicators for screening for drought tolerant wheat varieties and potentially higher yields. In addition, it is observed that improvement in any of these traits will lead to an increase in grain yield under water stress conditions.

Wheat Responses, Defence Mechanisms and Tolerance to Drought Stress: A Review Article

Wheat (Triticum aestivum L.) is one of the major basic stable crops grown worldwide, however, it is sensitive to environmental stresses like drought. With climate change, drought stress is becoming an increasingly severe constraint on wheat production which affects the plant growth and development, physiological functions, grain formation, grain quality and ultimately the yield. Various responses including biochemical, physiological, morphological, and molecular adaptations are shown by plants to survive in the drought stress condition. Drought escape, avoidance and tolerance are important coping mechanisms of wheat plant under drought environment. Several mechanisms such as accumulation of ABA, osmotic adjustment, and induction of dehydrins may confer drought tolerance by maintaining the high tissue water potential. As the root structure and root biomass define the pattern of water extraction from the soil, enhanced root and suppressed shoot growth resulting in higher root: shoot ratio facilitated plants to drought tolerance. The development of drought tolerance varieties becomes an important due to the uneven distribution of rainfall and water shortage. Some growth stage-specific physio-morphological traits are fundamental targets to breed drought-tolerant wheat varieties. Mutation breeding, molecular breeding, genome engineering techniques including gene pyramiding, gene stacking, and transgenics are employed to breed wheat for tolerance to abiotic stresses including drought. Omics decode the entire genome to have better understanding of plant molecular responses that will provide precise strategies for crop improvement. This paper discusses the wheat plant’s responses to drought stress, their defense mechanisms and modern techniques for the development of drought tolerant wheat varieties.

NIA-Shaheen (CIM-04-10): A high-yielding, drought-tolerant wheat variety

Abstract The wheat variety NIA-Shaheen (CIM-04-10) has high grain yield and modern plant architecture. It has wide adaptability, increased tiller production, bold grains, high starch and protein content, and good tolerance to disease and environmental stresses, particularly water stress. NIA-Shaheen has high yield potential (7184 kg ha-1).

Genome-Wide Association Mapping for Stomata and Yield Indices in Bread Wheat under Water Limited Conditions

Genome-wide association study (GWAS) was performed for stomata- and yield-related attributes with high-density Illumina 90 K Infinium SNP (single nucleotide polymorphism) array in bread wheat to determine genetic potential of germplasm for scarce water resources with sustainable yield potential. Major yield and stomata attributes were phenotyped on a panel of Pakistani and foreign accessions grown in non-stressed and water shortage environments during two seasons. Highly significant variations were shown among accessions in both conditions for examined characteristics. Water shortage conditions reduced the overall wheat yield and strong positive correlation existed among stomatal frequency, leaf venation and grain yield per plant. Population structure analyses based on 90,000 SNP data classified the accessions into four sub-populations which indicated the presence of genetic variability. Marker-trait association (MTA) analyses revealed that 422 significant SNPs at p ≤ 10−3, after crossing the false discovery rate (FDR) &lt;0.05 threshold, were linked with examined attributes. Pleiotropic loci (wsnp_Ex_c8913_14881924 and Tdurum_contig10598_304) were associated with flag leaf area (FLA), stomata size (SS), stomata frequency (SF), leaf venation (LV), number of grain per spike (NGS) and grain yield per plant (GYP), which were located on chromosome 4B and 6B at the positions 173.63cM and 229.64cM, respectively, under water shortage conditions. Pleotropic loci wsnp_Ex_c24167_33416760, wsnp_Ex_c5412_9564046 and Tdurum_contig81797_369 on chromosomes 7A, 2A and 4B at the positions 148.26cM, 261.05cM and 173.63cM, respectively, were significantly linked with stomata and yield indices such as FLA, SS, SF, LV, NGS and GYP under normal and water shortage conditions. The current experiment not only validated several MTAs for studied indices reported in other studies but also discovered novel MTAs significant under water shortage environments. Associated and significant SNPs will be useful in discovering novel genes underpinning water shortage tolerance in bread wheat for producing high-yielding and drought tolerant wheat varieties to fulfill the wheat demand for growing populations.

Learning from neighboring farmers: Does spatial dependence affect adoption of drought‐tolerant wheat varieties in China?

AbstractThe adoption of improved crop varieties, such as drought‐tolerant varieties, plays a crucial role in addressing climate change. In this study, we explore how and to what extent spatial interactions between farmers and neighboring farmers affect the adoption of drought‐tolerant wheat varieties (DTWVs), using data collected from rural households in China. A spatial Durbin probit model is utilized to identify the spatial patterns in DTWVs adoption. Results show that spatial dependence exists in DTWVs adoption. Spatial dependence is positively associated with wheat farmers’ DTWVs adoption decisions, and the spatial effects mainly arise from the neighboring farmers’ adoption decisions and information spillover via smartphone use and extension service contacts. Further analysis reveals that DTWVs adoption improves farm performance by increasing both wheat yields and farm profits significantly. Our findings underscore the necessity of considering spatial interactions between farmers when designing and promoting innovative agricultural technologies in rural areas.

The Effects of Some Seed Priming Treatments on Germination and Seedling Development in Wheat

Drought stress has negative effects on plant metabolism and growth. Seed priming is one of the ways used to strengthen crop plants at the seed stage against drought stress. In this study, the physiological effects of seed priming (1, 12, 24, and 48 hours) and foliar treatments of H2O2 (50  M) and GR24 (20  M) on 21 day old wheat seedlings (drought sensitive Triticum aestivum cv. 95 and drought tolerant cv. Tosunbey) were studied. The plant samples were used to determine the total chlorophyll content, total protein amount, root and stem length, seedling weight, and specific leaf area. Our results showed that only GR24 increased growth in the Tosunbey variety with seed priming. On the other hand, foliar GR24 was effective in both varieties against the detrimental effect of PEG induced osmotic stress, while foliar H2O2 treatment was effective only in the Tosunbey variety. Generally, it has been determined that the GR24 application supports the growth in both varieties, while the H2O2 treatment increases the growth only in drought tolerant wheat variety. Keywords: Wheat, Drought stress, Seed priming, GR24, H2O2, germination, growth. DOI: 10.7176/JSTR/7-05-01

Morphological, Physiological, and Biochemical Characterization of Drought-Tolerant Wheat (Triticum spp.) Varieties

Wheat is one of the most important cereal crops and extensively cultivated in wide ranges of altitudes in Ethiopia. With an alarming population growth in the era of climatic change, there is a need for further crop improvement for sustainable production. In this regard, the study was carried out at the Kulumsa Agricultural Research Center (KARC) in a rainout shelter to investigate the responses of durum and bread wheat varieties to soil water stress in terms of selected morphological, physiological, and biochemical parameters. The 2 factors were combined factorially and arranged in a randomized complete block design with 3 replications. The 12 wheat varieties, 6 bread wheat and other 6 durum wheat, were sown in pots under well-watered (100% field capacity) and water-stressed (30% field capacity) conditions. Results revealed that water stress resulted in 26%, 9%, 23%, 16%, and 11% reductions in plant height, spike length, number of spikelets spike−1, relative water, and chlorophyll contents, respectively. The tested wheat varieties under water stress produced 28% and 6% more proline content and total soluble sugar, respectively, as mitigation strategies against drought. Results further exhibited that wheat varieties significantly differed in all of the measured traits except for the plant height and relative water content. The present study verified that the biochemical parameters needs to be considered as better traits to select wheat (Triticum spp.) varieties for drought tolerance under water stress conditions.

Impact of climate resilient varieties on crop productivity in NICRA villages of Ratlam district in Madhya Pradesh

Rainfed agriculture which constitutes nearly 58 per cent of net cultivated area will be the most impacted. With this background, ICAR has launched a major network project, National Initiative on Climate Resilient Agriculture (NICRA), during 2010-11. In first phase 100 vulnerable districts were covered under this project adding 21 new districts second phase to undertake strategic research on adaption and mitigation, fill critical research gaps and demonstrate technologies on farmers’ fields to cope up with current climate variability and capacity building of different stakeholders. The impact of climate resilient varieties of crops was studied by KVK Jaora, Ratlam during 2017-18, 2018-19 and 2019-20 in NICRA village which Improved Water logging tolerant variety of Soybean RVS-2001-04 given higher yield of 42.0 per cent over traditional variety. The Drought tolerant wheat variety DBW-110 and IH-1605 in Rabi season contributed 21.0 per cent higher yield over local check variety Lok-1. The heat tolerant Chickpea variety JG-14 in Rabi season contributed 18.59 per cent higher yield over local variety.

Metabolic and physiological responses to progressive drought stress in bread wheat

Wheat (Tritium aestivum) is vulnerable to future climate change because it is predominantly grown under rain-fed conditions in drought-prone areas. Thus, in-depth understanding of drought effect on wheat metabolism is essential for developing drought-tolerant wheat varieties. Here, we exposed wheat ‘Norin 61’ plants to progressive drought stress [0 (before drought), 2, 4, 6, 8, and 10 days after withholding water] during the flowering stage to investigate physiological and metabolomic responses. Transcriptional analyses of key abscisic acid-responsive genes indicated that abscisic acid signalling played a major role in the adaptation of wheat to water deficit. Carbon isotope composition had a higher value than the control while canopy temperature (CT) increased under drought stress. The CT depression was tightly correlated with soil water potential (SWP). Additionally, SWP at − 517 kPa was identified as the critical point for increasing CT and inducing reactive oxygen species. Metabolome analysis identified four potential drought-responsive biomarkers, the enhancement of nitrogen recycling through purine and pyrimidine metabolism, drought-induced senescence based on 1-aminocyclopropane-1-carboxylic acid and Asn accumulation, and an anti-senescence response through serotonin accumulation under severe drought stress. Our findings provide in-depth insight into molecular, physiological and metabolite changes involved in drought response which are useful for wheat breeding programs to develop drought-tolerant wheat varieties.

Oxidative stress and antioxidant metabolites in wheat (Triticum aestivum L.) varieties during grain development under water deficit conditions

Two wheat (Triticum aestivum L.) varieties viz. WH 1105 and WH 1025 are subjected to drought stress. The non enzymatic antioxidant defense system which contains antioxidant metabolites such as ascorbic acid, glutathione and carotenoids contents were studied in drought sensitive and drought resistant varieties days after anthesis (DAA) in leaf and grain samples. As part of protective mechanism against drought, wheat plants produced more of ascorbic acid and glutathione with a concomitant decrease in carotenoid content. The increase in ascorbic acid and glutathione were more in WH 1025 than WH 1105. Carotenoids protect plants by minimizing ROS formation by quenching oxygen. The reduction in carotenoid content was observed in both wheat varieties days after anthesis (DAA) in leaf and grain samples but more reduction was observed in WH 1105 which is a drought sensitive variety of wheat. These antioxidant metabolites played a key role in protecting wheat plants against reactive oxygen species (ROS) mediated oxidative damage and their redox buffering capacity generates stress tolerance in drought tolerant wheat variety WH 1025.