scholarly journals The wheat Seven in Absentia gene is associated with increases in biomass and yield in hot climates

2019 ◽  
Author(s):  
Pauline Thomelin ◽  
Julien Bonneau ◽  
Chris Brien ◽  
Radoslaw Suchecki ◽  
Ute Baumann ◽  
...  
Keyword(s):  
Genetic Variation ◽  
Heat Stress ◽  
High Temperature ◽  
Heat Tolerance ◽  
Positional Cloning ◽  
Genomic Region ◽  
Sequence Variant ◽  
Positive Allele ◽  
Breeding Programmes ◽  
Seven In Absentia

AbstractWheat productivity is severely reduced by high temperatures. Breeding of heat tolerant cultivars can be achieved by identifying genes controlling physiological and agronomical traits with high temperature and using these to select superior genotypes, but no gene underlying genetic variation for heat tolerance has previously been described. We completed the positional cloning of qYDH.3BL, a quantitative trait locus (QTL) on bread wheat chromosome 3B associated with increased yield in hot and dry climates. The delimited genomic region contained 12 putative genes and a sequence variant in the promoter region of one gene - seven in absentia, TaSINA. This was associated with the QTL’s effects on early vigour, plant biomass and yield components in two distinct wheat populations grown under various growth conditions. Near isogenic lines carrying the positive allele at qYDH.3BL under-expressed TaSINA and had increased vigour and water use efficiency early in development, as well as increased biomass, grain number and grain weight following heat stress. A survey of worldwide distribution indicated that the positive allele became widespread from the 1950s through the CIMMYT wheat breeding programme but, to date, has been selected only in breeding programmes in Mexico and Australia.Significance statementWheat is the world’s most widely grown crop and a staple of human diet. Even brief episodes of high temperature in the growing season cause severe yield reductions. Finding and deploying genes for heat stress tolerance in new varieties is a priority for food security with climate change. We narrowed a genetic locus to a small genomic region where genetic variation was present only in one gene that showed clear differences of expression and improved yield and physiology under stress in the populations. Using diagnostic markers to track the positive haplotype in nearly 750 accessions, we found many regions where the allele could be used in breeding programmes to increase wheat’s heat tolerance.

scholarly journals The wheat Seven in Absentia gene is associated with increases in biomass and yield in hot climates

2021 ◽  
Author(s):  
Pauline Thomelin ◽  
Julien Bonneau ◽  
Chris Brien ◽  
Radoslaw Suchecki ◽  
Ute Baumann ◽  
...  
Keyword(s):  
High Temperatures ◽  
Positional Cloning ◽  
Plant Biomass ◽  
Wheat Chromosome ◽  
Triticum Aestivum L ◽  
Growth Conditions ◽  
Wheat Breeding ◽  
Sequence Variant ◽  
Positive Allele ◽  
Seven In Absentia

Abstract Wheat (Triticum aestivum L.) productivity is severely reduced by high temperatures. Breeding of heat tolerant cultivars can be achieved by identifying genes controlling physiological and agronomical traits when high temperatures occur and using these to select superior genotypes, but no gene underlying genetic variation for heat tolerance has previously been described. We advanced the positional cloning of qYDH.3BL, a quantitative trait locus (QTL) on bread wheat chromosome 3B associated with increased yield in hot and dry climates. The delimited genomic region contained 12 putative genes and a sequence variant in the promoter region of one gene, Seven in absentia, TaSINA. This was associated with the QTL’s effects on early vigour, root growth, plant biomass and yield components in two distinct wheat populations grown under various growth conditions. Near isogenic lines carrying the positive allele at qYDH.3BL under-expressed TaSINA and had increased vigour and water use efficiency early in development, as well as increased biomass, grain number and grain weight following heat stress. A survey of worldwide distribution indicated that the positive allele became widespread from the 1950s through the CIMMYT wheat breeding programme but, to date, has been selected only in breeding programmes in Mexico and Australia.

Effect of Timing of Heat Stress During Grain Filling on Two Wheat Varieties Differing in Heat Tolerance. II. Fractional Protein Accumulation

1996 ◽  
Vol 23 (6) ◽  
pp. 739 ◽  
Author(s):  
PJ Stone ◽  
ME Nicolas
Keyword(s):  
Heat Stress ◽  
High Temperature ◽  
Grain Growth ◽  
Heat Tolerance ◽  
Grain Filling ◽  
Size Exclusion ◽  
Protein Accumulation ◽  
Wheat Varieties ◽  
Grain Filling Period ◽  
Very High

Short periods of very high temperature (> 35�C) are common during the grain filling period of wheat, and can significantly alter mature protein composition and consequently grain quality. This study was designed to determine the stage of grain growth at which fractional protein accumulation is most sensitive to a short heat stress, and to examine whether varietal differences in heat tolerance are expressed consistently throughout the grain filling period. Two varieties of wheat differing in heat tolerance (cvv. Egret and Oxley, tolerant and sensitive, respectively) were exposed to a short (5 day) period of very high temperature (40�C max, for 6 h each day) at 5-day intervals throughout grain filling, from 15 to 50 days after anthesis. Grain samples were taken throughout grain growth and analysed for protein content and composition (albumin/globulin, monomer, SDS-soluble polymer and SDS-insoluble polymer) using size-exclusion high-performance liquid chromatography. The timing of heat stress exerted a significant influence on the accumulation of total wheat protein and its fractions, and protein fractions differed in their responses to the timing of heat stress. Furthermore, wheat genotype influenced both the sensitivity of fractional protein accumulation to heat stress and the stage during grain filling at which maximum sensitivity to heat stress occurred.

scholarly journals Effect of Heat Treatment on Physiological and Recovery Growth Status of Two Tomato Cultivars With Different Heat Susceptibility

2021 ◽  
Author(s):  
Sherzod Nigmatullayevich Rajametov ◽  
Eun Young Yang ◽  
Hyo Bong Jeong ◽  
Myeong Cheoul Cho ◽  
Soo-Young Chae ◽  
...  
Keyword(s):  
Heat Stress ◽  
High Temperature ◽  
Stress Tolerance ◽  
Heat Tolerance ◽  
Fruit Set ◽  
Fruit Size ◽  
Seedling Stage ◽  
Screening Methods ◽  
Tomato Cultivars ◽  
Heat Tolerant

High temperature seriously effects on plant vegetative and reproductive development and reduces productivity of plants, while to increase crop yield is the main target in most crop heat stress tolerance improvement breeding programs, not just survival, under high temperature. Our aim was to compare temperature stress tolerance in two commercial tomato cultivars “Dafnis” (big fruit size) and “Minichal” (cherry fruit size) to develop early screening methods and find out survival rate and physiological responses of tomato cultivars on high temperature (40°C and within 70% RH, day/night) in 4-5 true leaf seedling stage- (4LS) and identifies the linkage of heat tolerance with fruit set and leaf heat damage rates (LHD) in seedling stage with subsequent vegetative traits at recovery. Results showed that heat stress significantly affected on physiological-chemical and vegetative parameters of seedlings regardless of tomato cultivars. Survival and the threshold level of high temperature tolerance in the seedlings of cv. “Dafnis” and “Minichal” were identified on days 7 and 9, respectively. Our findings revealed that photosynthesis (PN, Gs, Ci, Tr) parameters were increased and CHL content persisted steady value in cv. “Minichal” during heat stress period, however EC and RPL rates were lower than cv. “Dafnis”. Heat stress reduced the SFW in both cultivars in seedling stage, but PH and RFW were significantly decreased in the heat tolerant cv. “Minichal”, whereas this parameters were not significantly ranged in the heat susceptible cv. “Dafnis”. Additionally, there no found linkage between vegetative parameters with decreasing of PN and CHL rates during HT of seedlings. In plants of cv. “Minichal” with LHD-25, 50 and 75% were no found significant differences in PH, whereas in cv. “Dafnis” significant differences were determined in plants with LHD-75%, and the significant differences in rates of SFW and RFW were observed in plants of cv. “Dafnis” having LHD-75% for 28 days of recovery at NT condition. Taken together, we concluded that heat stress affected on physiological parameters regardless of tolerance level, and to identify heat tolerant genotype in tomato breeding program, screening and selection genotypes have to be evaluated at the vegetative and reproductive stages with consideration fruit size types. Since we could not find linkage between heat tolerances in seedling stage with fruit set at the reproductive stage and fruit set cannot be used as a general predictor of heat tolerance.

Molecular breeding for improving heat stress tolerance in wheat.

2021 ◽  
pp. 82-89
Author(s):  
Kuo-hai Yu ◽  
Hui-ru Peng ◽  
Zhong-fu Ni ◽  
Ying-yin Yao ◽  
Zhao-rong Hu ◽  
...  
Keyword(s):  
Heat Stress ◽  
Heat Tolerance ◽  
Molecular Basis ◽  
Molecular Genetic ◽  
Wheat Breeding ◽  
Heat Response ◽  
Breeding Programmes ◽  
Resource Exploration ◽  
Heat Stress Tolerance

Abstract This paper discusses wheat responses to heat stress (including morphological and growth, cellular structure and physiological responses) and the molecular-genetic bases of heat response in wheat (including topics on mapping quantitative trait loci related to heat tolerance and the role of functional genes in response to heat stress). The improvement of heat tolerance of wheat by comprehensive strategies is also described. It is believed that with the emphasis on genetic resource exploration and with better understanding of the molecular basis, heat tolerance will be improved during wheat breeding programmes in the future.

Agronomic, physiological and molecular characterisation of rice mutants revealed the key role of reactive oxygen species and catalase in high-temperature stress tolerance

2020 ◽  
Vol 47 (5) ◽  
pp. 440 ◽  
Author(s):  
Syed Adeel Zafar ◽  
Amjad Hameed ◽  
Muhammad Ashraf ◽  
Abdus Salam Khan ◽  
Zia-ul- Qamar ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Heat Stress ◽  
High Temperature ◽  
Grain Yield ◽  
Temperature Stress ◽  
Heat Tolerance ◽  
High Temperature Stress ◽  
Oxygen Species ◽  
Selection Indices ◽  
Heat Tolerant

Climatic variations have increased the occurrence of heat stress during critical growth stages, which negatively affects grain yield in rice. Plants adapt to harsh environments, and particularly high-temperature stress, by regulating their physiological and biochemical processes, which are key tolerance mechanisms. The identification of heat-tolerant rice genotypes and reliable selection indices are crucial for rice improvement programs. Here, we evaluated the response of a rice mutant population for high-temperature stress at the seedling and reproductive stages based on agronomic, physiological and molecular indices. Estimates of variance components revealed significant differences (P < 0.001) among genotypes, treatments and their interactions for almost all traits. The principal component analysis showed significant diversity among genotypes and traits under high-temperature stress. The mutant HTT-121 was identified as the most heat-tolerant mutant with higher grain yield, panicle fertility, cell membrane thermo-stability (CMTS) and antioxidant enzyme levels under heat stress. Various seedling-based morpho-physiological traits (leaf fresh weight, relative water contents, malondialdehyde, CMTS) and biochemical traits (superoxide dismutase, catalase and hydrogen peroxide) explained variations in grain yield that could be used as selection indices for heat tolerance in rice during early growth. Notably, heat-sensitive mutants accumulated reactive oxygen species, reduced catalase activity and upregulated OsSRFP1 expression under heat stress, suggesting their key roles in regulating heat tolerance in rice. The heat-tolerant mutants identified in this study could be used in breeding programs and to develop mapping populations to unravel the underlying genetic architecture for heat-stress adaptability.

scholarly journals Genetic variations, heritability, heat tolerance indices and correlations studies for traits of bread wheat genotypes under high temperature

2019 ◽  
Vol 11 (5) ◽  
pp. 672-686
Author(s):  
Elfadil Mohamed Elbashier ◽  
Elfadil Mohammed Eltayeb Elbashier ◽  
Siddig Esa Idris2 ◽  
Wuletaw Tadesse ◽  
Izzat S.A. Tahir ◽  
...  
Keyword(s):  
Heat Stress ◽  
High Temperature ◽  
Grain Yield ◽  
Bread Wheat ◽  
Heat Tolerance ◽  
Agricultural Research ◽  
Canopy Temperature ◽  
Content Type ◽  
Wheat Genotypes ◽  
Tolerance Indices

PurposeThe purpose of this paper was to study the genetic variability, heritability, heat tolerance indices and phenotypic and genotypic correlation studies for traits of 250 elite International Center for Agricultural Research in the Dry Areas (ICARDA) bread wheat genotypes under high temperature in Wad Medani, Center in Sudan.Design/methodology/approachBread wheat is an important food on a global level and is used in the form of different products. High temperature associated with climate change is considered to be a detrimental stress in the future on world wheat production. A total of 10,250 bread wheat genotypes selected from different advanced yield trials introduction from ICARDA and three checks including were grown in two sowing dates (SODs) (1st and 2nd) 1st SOD heat stress and 2nd SOD non-stress at the Gezira Research Farm, of the Agricultural Research Corporation, Wad Medani, Sudan.FindingsAn alpha lattice design with two replications was used to assess the presence of phenotypic and genotypic variations of different traits, indices for heat stress and heat tolerance for 20 top genotypes and phenotypic and genotypic correlations. Analysis of variance revealed significant differences among genotypes for all the characters. A wide range, 944-4,016 kg/ha in the first SOD and 1,192-5,120 kg/ha in the second SOD, was found in grain yield. The average yield on the first SOD is less than that of the secondnd SOD by 717.7 kg/ha, as the maximum and minimum temperatures were reduced by 3ºC each in the second SOD when compared to the first SOD of the critical stage of crop growth shown.Research limitations/implicationsSimilar wide ranges were found in all morpho-physiological traits studied. High heritability in a broad sense was estimated for days to heading and maturity. Moderate heritability estimates found for grain yield ranged from 44 to 63.6 per cent, biomass ranged from 37.8 to 49.1 per cent and canopy temperature (CT) after heading ranged from 44.2 to 48 per cent for the first and secondnd SODs. The top 20 genotypes are better than the better check in the two sowing dates and seven genotypes (248, 139, 143, 27, 67, 192 and 152) were produced high grain yield under both 1st SOD and 2nd SOD.Practical implicationsThe same genotypes in addition to Imam (check) showed smaller tolerance (TOL) values, indicating that these genotypes had a smaller yield reduction under heat-stressed conditions and that they showed a higher heat stress susceptibility index (SSI). A smaller TOL and a higher SSI are favored. Both phenotypic and genotypic correlations of grain yield were positively and significantly correlated with biomass, harvest index, number of spikes/m2, number of seeds/spike and days to heading and maturity in both SODs and negatively and significantly correlated with canopy temperature before and after heading in both SODs.Originality/valueGenetic variations, heritability, heat tolerance indices and correlation studies for traits of bread wheat genotypes under high temperature

Assessing genetic variation for heat stress tolerance in Indian bread wheat genotypes using morpho-physiological traits and molecular markers

2016 ◽  
Vol 15 (6) ◽  
pp. 539-547 ◽  
Author(s):  
P. Sharma ◽  
S. Sareen ◽  
M. Saini ◽  
Shefali
Keyword(s):  
Genetic Diversity ◽  
Genetic Variation ◽  
Heat Stress ◽  
Molecular Markers ◽  
Heat Tolerance ◽  
Polymorphic Information Content ◽  
Physiological Traits ◽  
Phenotypic Traits ◽  
Phenotypic Data ◽  
Wheat Genotypes

AbstractHeat stress greatly limits the productivity of wheat in many regions. Knowledge on the degree of genetic diversity of wheat varieties along with their selective traits will facilitate the development of high yielding, stress-tolerant wheat cultivar. The objective of this study were to determine genetic variation in morpho-physiological traits associated with heat tolerance in 30 diverse wheat genotypes and to examine genetic diversity and relationship among the genotypes varying heat tolerance using molecular markers. Phenotypic data of 15 traits were evaluated for heat tolerance under non-stress and stress conditions for two consecutive years. A positive and significant correlation among cell membrane stability, canopy temperature depression, biomass, susceptibility index and grain yield was shown. Genetic diversity assessed by 41 polymorphic simple sequence repeat (SSR) markers was compared with diversity evaluated for 15 phenotypic traits averaged over stress and non-stress field conditions. The mean polymorphic information content for SSR value was 0.38 with range of 0.12–0.75. Based on morpho-physiological traits and genotypic data, three groups were obtained based on their tolerance (HHT, MHT and LHT) levels. Analysis of molecular variance explained 91.7% of the total variation could be due to variance within the heat tolerance genotypes. Genetic diversity among HHT was higher than LHT genotypes and HHT genotypes were distributed among all cluster implied that genetic basis of heat tolerance in these genotypes was different thereby enabling the wheat breeders to combine these diverse sources of genetic variation to improve heat tolerance in wheat breeding programme.

scholarly journals Protective Effects of Salicylic Acid and Calcium Chloride on Sage Plants (Salvia officinalis L. and Salvia elegans Vahl) under High-Temperature Stress

Plants ◽  
2021 ◽  
Vol 10 (10) ◽  
pp. 2110
Author(s):  
Kuan-Hung Lin ◽  
Tse-Yen Lin ◽  
Chun-Wei Wu ◽  
Yu-Sen Chang
Keyword(s):  
Salicylic Acid ◽  
Heat Stress ◽  
High Temperature ◽  
Calcium Chloride ◽  
Temperature Stress ◽  
Heat Tolerance ◽  
Combined Treatment ◽  
High Temperature Stress ◽  
Fresh Market ◽  
Time Intervals

High-temperature stress is a major risk to fresh-market Salvia production, and heat intolerance is a major constraint in sage cultivation, particularly during the hot summer season. Previously, we investigated heat tolerance in five common-market cultivars of sage plants using leaf relative injury (RI) values and found that S. elegans Vahl (SE) and S. officinalis L. (SO) were the most and least heat-tolerant species, respectively. The exogenous applications of salicylic acid (SA) and calcium chloride (CaCl2) to alleviate heat stress in various species have been extensively studied, but reports of the effects of SA and CaCl2 treatments on the heat tolerance of sage plants are scarce. The objective of this study was to investigate how SA and CaCl2 affect the physiology and morphology of SE and SO plants under high-temperature conditions. Potted plants were pretreated with SA (0, 100, 200, 400, and 800 μM) and CaCl2 (0, 5, 10, and 15 mM), alone and combined, exposed to 55 °C and 80% humidity for 30 min, then placed in an environment-controlled chamber at 30°C for three days and evaluated for changes in phenotypic appearance, RI, spectral reflectance, and chlorophyll fluorescence indices at different time intervals. Plants watered without chemical solutions were used as controls. Our results show that the growth of SO plants pretreated with SA and CaCl2 was more robust, compared with control plants, which were considerably affected by heat stress, resulting in brown, withered leaves and defoliation. The effects of the combined applications of SA (100 μM) and CaCl2 (5 mM) to SO plants were superior to control plants in increasing values of soil-plant analysis development (SPAD), normalized difference vegetation index (NDVI), and the maximal quantum yield of photosystemII photochemistry (Fv/Fm), while reducing RI%. Furthermore, SO plants exhibited higher SPAD and Fv/Fm values and lower RI% than SE plants in combined treatments at all time intervals after heat stress, implying that different genotypes displayed variations in their SPAD, Fv/Fm, and RI%. Thus, a combined treatment of 100 μM of SA and 5 mM of CaCl2 is effective and beneficial to plant appearance and ability to ameliorate heat stress. These indices can be used as indicators to characterize the physiology of these plants and applied on a commercial scale for informing the development of rapid and precise management practices on bedded sage plants grown in plant factories to achieve maximum market benefit.

scholarly journals Heat-induced Leaf Senescence and Hormonal Changes for Thermal Bentgrass and Turf-type Bentgrass Species Differing in Heat Tolerance

2007 ◽  
Vol 132 (2) ◽  
pp. 185-192 ◽  
Author(s):  
Yan Xu ◽  
Bingru Huang
Keyword(s):  
Heat Stress ◽  
High Temperature ◽  
Leaf Senescence ◽  
Heat Tolerance ◽  
Photochemical Efficiency ◽  
Creeping Bentgrass ◽  
Zeatin Riboside ◽  
Hormonal Changes ◽  
Heat Tolerant ◽  
Aba Content

Leaf senescence can be induced by many environmental stresses, including supraoptimal temperatures. The objectives of this study were to evaluate leaf senescence induced by heat stress for two Agrostis species contrasting in heat tolerance and to examine whether heat-induced leaf senescence in both species was associated with changes in three major senescence-related hormones: ethylene, abscisic acid (ABA), and cytokinins. Plants of heat-tolerant rough bentgrass (Agrostis scabra Willd.) and heat-sensitive creeping bentgrass (Agrostis stolonifera L.) were exposed to 35/30 °C (day/night) (high temperature) or 20/15 °C (control) for 35 d in growth chambers. Turf quality, photochemical efficiency (Fv/Fm), and the contents of two pigments (chlorophyll and carotenoid) for both species decreased under high temperature; however, heat-tolerant A. scabra exhibited delayed and less severe decline in all parameters compared with heat-sensitive A. stolonifera. Ethylene production rate increased in both species at 35 °C, but the increase was observed 21 days later in A. scabra compared with that in A. stolonifera. ABA content increased at the initiation of heat stress and then declined in both species after prolonged heat stress. However, the timing of the increase was delayed for 7 days and the highest level of ABA content was less in A. scabra (4.0 times that of the control) than that in A. stolonifera (5.9 times that of the control). Decreases in both forms of cytokinins (transzeatin/zeatin riboside and isopentenyl adenosine) were also delayed for 14 days and less pronounced in A. scabra. Correlation analysis revealed that leaf senescence induced by heat stress was negatively correlated to ethylene and ABA accumulation and positively correlated to cytokinin production. Delayed leaf senescence in A. scabra under heat stress could be related to slower and less magnitude of changes in ethylene, ABA, and cytokinins.

From qualitative to quantitative: a new approach for determining heat tolerance in cotton using triphenyl tetrazolium chloride

2020 ◽  
Author(s):  
Susan Yvonne Jaconis ◽  
Warren C Conaty ◽  
Alan J. E. Thompson ◽  
Shanna L Smith ◽  
Chiara Trimarchi ◽  
...  
Keyword(s):  
Heat Stress ◽  
High Temperature ◽  
Temperature Stress ◽  
Heat Tolerance ◽  
High Temperature Stress ◽  
Triphenyl Tetrazolium Chloride ◽  
Improvement Program ◽  
Breeding Programs ◽  
Tetrazolium Chloride ◽  
Viability Testing

Abstract Background Susceptibility of cotton to heat stress in cotton production systems is a major concern for breeding programs. It is hypothesised that in order to maintain or improve cotton yields and quality in sub-optimal future climates, the negative effects of high temperature stress must be mitigated. To address this need, a fast and effect way of quantifying thermotolerant phenotypes is required. Triphenyl tetrazolium chloride (TTC) based enzyme viability testing following high temperature stress can be used as a heat tolerance phenotype. This is because when live cells encounter a TTC solution, TTC undergoes a chemical reduction producing a visible, insoluble red product called triphenyl formazan, that can be quantified spectrophotometrically. However, existing TTC based cell viability assays cannot easily be deployed at the scale required in a crop improvement program. Results In this study, a heat stress assay (HSA) based on the use of TTC enzyme viability testing has been refined and improved for efficiency, reliability, and ease of use through four experiments. Sampling factors which may influence assay results such as leaf age, plant water status, and short-term cold storage were also investigated. Experiments conducted in this study have successfully down scaled the assay and identified an optimal sampling regime, enabling measurement of large segregating populations for application in breeding programs. The optimal durations of leaf disc exposure to TTC and the subsequent extraction of the formazan product in ethanol were identified as 16 h and 13 h, respectively; leading to enhanced clarity of assay results. Conclusions These improvements in the methodology provide a new level of confidence in results, ensuring applicability of the assay to a breeding program. The improved HSA methodology is important as it is proposed that long-term improvements in cotton thermotolerance can be achieved through concurrent selection of superior phenotypes based on the HSA and yield performance in hot environments. Additionally, a new way of interpreting both heat tolerance and heat resistance were developed to differentiate genotypes that perform well at the time of a heat stress event and those that maintain a similar level of performance to a non-stressed control.

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