scholarly journals Variation for Heat Tolerance During Seed Germination in Diverse Carrot [Daucus carota (L.)] Germplasm

HortScience ◽  
2019 ◽  
Vol 54 (9) ◽  
pp. 1470-1476 ◽  
Author(s):  
Adam Bolton ◽  
Aneela Nijabat ◽  
Muhammad Mahmood-ur-Rehman ◽  
Naima Huma Naveed ◽  
A.T.M. Majharul Mannan ◽  
...  
Keyword(s):  
Heat Stress ◽  
Seed Germination ◽  
Stress Tolerance ◽  
Heat Tolerance ◽  
Inbred Lines ◽  
Plant Introductions ◽  
Wild Carrot ◽  
Carrot Seed ◽  
Heat Stress Tolerance ◽  
Heat Tolerant

Carrot production is constrained by high levels of heat stress during the germination stage in many global regions. Few studies have been published evaluating the effect of heat stress on carrot seed germination or screening for genetic heat stress tolerance. The objectives of this study were to evaluate the response of diverse carrot germplasm to heat stress, identify heat-tolerant germplasm that may be used by plant breeders, and define the appropriate temperature for assessing heat tolerance in germinating carrot seed. To identify an appropriate screening temperature, three commercial hybrids and an open pollinated variety were evaluated at five temperatures (24, 32.5, 35, 37.5, and 40 °C). In preliminary studies, 35 °C was identified as the optimal temperature for screening heat tolerance of carrot seed. Cultivated and wild carrot plant introductions (PIs) (n = 270) from the U.S. Department of Agriculture (USDA) National Plant Germplasm System (NPGS) representing 41 countries, inbred lines from the USDA Agricultural Research Service (n = 15), and widely grown commercial hybrids (n = 8) were evaluated for heat tolerance under heat stress and nonstress conditions (35 °C and 24 °C, respectively) by calculating absolute decrease in percent germination (AD), inhibition index (II), relative heat tolerance (RHT), and heat tolerance index (HTI). All measurements of heat tolerance identified significant differences among accessions; AD ranged from −13.0% to 86.7%, II ranged from 35.7% to 100.0%, RHT ranged from 0 to 1.36, and HTI ranged from 0.0 to 1.45. The broad-sense heritability (H2) calculations ranged from 0.64 to 0.86 for different traits, indicating a moderately strong genetic contribution to the phenotypic variation. Several wild carrot accessions and inbred lines displayed low levels of heat tolerance, whereas cultivated accessions PI 643114 (United States), PI 652400 and PI 652403 (Turkey), PI 652208 (China), and PI 652403 (Russia) were most heat tolerant. This is the first evaluation of heritability for heat stress tolerance during carrot seed germination, the first measure of HTI, and the first correlation calculation between heat and salt tolerance during germination in carrot.

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.

scholarly journals Morpho-physiological traits associated with heat stress tolerance in tropical maize (Zea mays L.) at reproductive stage

2019 ◽  
Vol 13 ((04) 2019) ◽  
pp. 536-545 ◽  
Author(s):  
Jewel Jameeta Noor ◽  
M.T. Vinayan ◽  
Shahid Umar ◽  
Pooja Devi ◽  
Muhammad Iqbal ◽  
...  
Keyword(s):  
Heat Stress ◽  
Grain Yield ◽  
Stress Tolerance ◽  
Inbred Lines ◽  
Physiological Traits ◽  
Optimal Temperature ◽  
Tropical Maize ◽  
Important Trait ◽  
Heat Stress Tolerance ◽  
Secondary Traits

Heat stress resilience has emerged as an important trait in maize hybrids targeted for post–monsoon spring cultivation in large parts of South Asia and many other parts of the tropics. Selection based on grain yield alone under heat stress is often misleading, and therefore an approach involving stress-adaptive secondary traits along with grain yield could help in the development of improved, stable heat stress tolerant cultivars. We attempted to identify reliable and effective secondary traits associated with heat stress tolerance in tropical maize and sources of heat stress tolerant germplasm. A panel of 99 elite maize inbred lines representing the wider genetic diversity of tropical maize and a set of 58 elite hybrids were phenotyped under natural heat stress and optimal temperature for grain yield and 15 secondary traits including 10 morpho-physiological traits and 5 yield attributes. Evaluation under natural heat stress was done during the spring season by adjusting the planting date so that the complete reproductive stage (from tassel emergence to late grain filling) was exposed to heat stress. The optimal temperature trial was planted during the monsoon season with no exposure to heat stress at any crop stage. Heat stress significantly affected most of the observed traits. Among the traits studied two yield attributing traits, i.e.- ears per plant (EPP) and kernel per row (KPR), and three morpho-physiological traits, i.e.- chlorophyll content (CC), leaf firing (LF) and tassel blast (TB) were found to be the key secondary traits associated with grain yield under heat stress. In addition, low anthesis-silking internal (ASI) is an important trait that needs to be added in the index selection for heat stress tolerance. The study identified nine promising heat stress tolerant maize inbred lines with desirable secondary traits and grain yield under severe heat stress, which could be used as source germplasm in heat stress tolerance maize breeding program.

scholarly journals The genetic and molecular basis for improving heat stress tolerance in wheat

aBIOTECH ◽  
2021 ◽  
Author(s):  
Lv Sun ◽  
Jingjing Wen ◽  
Huiru Peng ◽  
Yingyin Yao ◽  
Zhaorong Hu ◽  
...  
Keyword(s):  
Heat Stress ◽  
Stress Tolerance ◽  
Heat Tolerance ◽  
Genetic Basis ◽  
Molecular Mechanisms ◽  
Elevated Temperatures ◽  
New Technologies ◽  
Wheat Breeding ◽  
Heat Stress Tolerance ◽  
The Impact

AbstractWheat production requires at least ~ 2.4% increase per year rate by 2050 globally to meet food demands. However, heat stress results in serious yield loss of wheat worldwide. Correspondingly, wheat has evolved genetic basis and molecular mechanisms to protect themselves from heat-induced damage. Thus, it is very urgent to understand the underlying genetic basis and molecular mechanisms responsive to elevated temperatures to provide important strategies for heat-tolerant varieties breeding. In this review, we focused on the impact of heat stress on morphology variation at adult stage in wheat breeding programs. We also summarize the recent studies of genetic and molecular factors regulating heat tolerance, including identification of heat stress tolerance related QTLs/genes, and the regulation pathway in response to heat stress. In addition, we discuss the potential ways to improve heat tolerance by developing new technologies such as genome editing. This review of wheat responses to heat stress may shed light on the understanding heat-responsive mechanisms, although the regulatory network of heat tolerance is still ambiguous in wheat.

scholarly journals Carbohydrate Accumulation in Relation to Heat Stress Tolerance in Two Creeping Bentgrass Cultivars

2000 ◽  
Vol 125 (4) ◽  
pp. 442-447 ◽  
Author(s):  
Xiaozhong Liu ◽  
Bingru Huang
Keyword(s):  
Heat Stress ◽  
Stress Tolerance ◽  
Heat Tolerance ◽  
Creeping Bentgrass ◽  
Carbohydrate Accumulation ◽  
Physiological Factors ◽  
Root Mortality ◽  
Carbohydrate Availability ◽  
Turf Quality ◽  
Heat Stress Tolerance

Understanding physiological factors that may confer heat tolerance would facilitate breeding for improvement of summer turf quality. The objective of this study was to investigate whether carbohydrate availability contributes to changes in turf quality and root mortality during heat stress in two creeping bentgrass [Agrostis stolonifera L. var. palustris (Huds.) Farw. (syn. A. palustris Huds.)] cultivars, `L-93' and `Penncross', that contrast in heat tolerance. Grasses were grown at 14-hour days and 11-hour nights of 22/16 °C (control) and 35/25 °C (heat stress) for 56 days in growth chambers. Turf quality decreased while root mortality increased under heat-stress conditions for both cultivars, but to a greater extent for `Penncross' than `L-93'. The concentrations of total nonstructural carbohydrate (TNC), fructans, starch, glucose, and sucrose in shoots (leaves and stems) and roots decreased at 35/25 °C. The reduction in carbohydrate concentrations of shoots was more pronounced than that of roots. Shoot glucose and sucrose concentrations were more sensitive to heat stress than other carbohydrates. `L-93' maintained significantly higher carbohydrate concentrations, especially glucose and sucrose, than `Penncross' at 35/25 °C. Results suggest that high carbohydrate availability, particularly glucose and sucrose, during heat stress was an important physiological trait associated with heat-stress tolerance in creeping bentgrass.

scholarly journals Development of an in vitro Microtuberization and Temporary Immersion Bioreactor System to Evaluate Heat Stress Tolerance in Potatoes (Solanum tuberosum L.)

2021 ◽  
Vol 12 ◽  
Author(s):  
Sanjeev Gautam ◽  
Nora Solis-Gracia ◽  
Megan K. Teale ◽  
Kranthi Mandadi ◽  
Jorge A. da Silva ◽  
...  
Keyword(s):  
Heat Stress ◽  
High Temperature ◽  
Stress Tolerance ◽  
Heat Tolerance ◽  
Potato Variety ◽  
Temporary Immersion Bioreactor ◽  
Temporary Immersion ◽  
Bioreactor System ◽  
Heat Tolerant

High temperature (heat) stress reduces tuber yield and quality of potatoes. Screening potatoes for heat tolerance is increasingly important, considering the climate change scenario and expansion of potatoes to countries where heat stress is an issue. In vitro screening for tolerance to abiotic stresses offers several advantages, including quick evaluation of numerous genotypes (clones) in reduced space, controlled environmental conditions (temperature and photoperiod), and free from confounding variables inherent to greenhouse and field conditions. In this study, we explored the feasibility of using a temporary immersion bioreactor system for heat tolerance screening of potatoes. We determined the best hormone-free microtuberizing media for this system (MSG with 8% sucrose) to enhance microtuber number and size. Comparisons of microtubers produced at 30°C as heat treatment, with 16°C as normal condition, allowed to identify heat tolerant and susceptible potato clones. The use of bioreactors allowed distinguishing well-formed (non-deformed) from deformed microtubers. Heat stress increased the total biomass of plant tissues in all the clones. However, the effect of heat stress on microtuber number and weight varied among the clones. Incubation at 30°C decreased the weight and number of non-deformed microtubers in all the clones except for Reveille Russet in which the weight of non-deformed microtubers was significantly increased and the count of non-deformed microtubers was not affected. The potato variety Reveille Russet, which was selected under high-temperature field conditions in Texas, had many non-deformed microtubers per explant and the highest microtuber weight among four clones evaluated under heat stress. We described a faster and reliable in vitro microtuberization system for abiotic stress tolerance screening, identified Reveille Russet as a promising heat-tolerant potato variety, and confirmed Russet Burbank and Atlantic as susceptible heat-tolerant checks.

Cytosolic HSC70s repress heat stress tolerance and enhance seed germination under salt stress conditions

2021 ◽  
Author(s):  
Huimei Zhao ◽  
Asad Jan ◽  
Naohiko Ohama ◽  
Satoshi Kidokoro ◽  
Fumiyuki Soma ◽  
...  
Keyword(s):  
Salt Stress ◽  
Heat Stress ◽  
Seed Germination ◽  
Stress Tolerance ◽  
Stress Conditions ◽  
Heat Stress Tolerance

scholarly journals Major QTLs and Potential Candidate Genes for Heat Stress Tolerance Identified in Chickpea (Cicer arietinum L.)

2021 ◽  
Vol 12 ◽  
Author(s):  
Uday Chand Jha ◽  
Harsh Nayyar ◽  
Ramesh Palakurthi ◽  
Rintu Jha ◽  
Vinod Valluri ◽  
...  
Keyword(s):  
Heat Stress ◽  
Heat Shock ◽  
Stress Tolerance ◽  
Candidate Genes ◽  
Cicer Arietinum ◽  
Nitrogen Balance ◽  
Major Qtls ◽  
Heat Stress Tolerance ◽  
Heat Tolerant ◽  
Balance Index

In the context of climate change, heat stress during the reproductive stages of chickpea (Cicer arietinum L.) leads to significant yield losses. In order to identify the genomic regions responsible for heat stress tolerance, a recombinant inbred line population derived from DCP 92-3 (heat sensitive) and ICCV 92944 (heat tolerant) was genotyped using the genotyping-by-sequencing approach and evaluated for two consecutive years (2017 and 2018) under normal and late sown or heat stress environments. A high-density genetic map comprising 788 single-nucleotide polymorphism markers spanning 1,125 cM was constructed. Using composite interval mapping, a total of 77 QTLs (37 major and 40 minor) were identified for 12 of 13 traits. A genomic region on CaLG07 harbors quantitative trait loci (QTLs) explaining >30% phenotypic variation for days to pod initiation, 100 seed weight, and for nitrogen balance index explaining >10% PVE. In addition, we also reported for the first time major QTLs for proxy traits (physiological traits such as chlorophyll content, nitrogen balance index, normalized difference vegetative index, and cell membrane stability). Furthermore, 32 candidate genes in the QTL regions that encode the heat shock protein genes, heat shock transcription factors, are involved in flowering time regulation as well as pollen-specific genes. The major QTLs reported in this study, after validation, may be useful in molecular breeding for developing heat-tolerant superior lines or varieties.

scholarly journals A conserved HSF:miR169:NF-YA loop involved in tomato and Arabidopsis heat stress tolerance

2021 ◽  
Author(s):  
Sombir Rao ◽  
Chandni Bansal ◽  
Celine Sorin ◽  
Martin Crespi ◽  
Saloni Mathur
Keyword(s):  
Transcriptional Regulation ◽  
Transcription Factors ◽  
Heat Stress ◽  
Stress Tolerance ◽  
Heat Tolerance ◽  
Critical Role ◽  
Negative Regulator ◽  
Virus Induced Gene Silencing ◽  
Heat Stress Response ◽  
Heat Stress Tolerance

AbstractHeat stress transcription factors (HSFs) and miRNAs regulate different stress and developmental networks in plants. Regulatory feedbacks are at the basis of these networks. Here, we report that plants improve their heat stress tolerance through HSF-mediated transcriptional regulation of MIR169 and post-transcriptional regulation of NF-YA transcription factors. We show that HSFs recognize tomato and Arabidopsis MIR169 promoters using yeast-one-hybrid/ChIP-qPCR. Silencing tomato HSFs using virus induced gene silencing (VIGS) reduced Sly-MIR169 levels and enhanced Sly-NF-YA9/A10 target expression. Further, Sly-NF-YA9/A10-VIGS knock-down tomato plants and Arabidopsis plants overexpressing At-MIR169d or At-nf-ya2 mutants showed a link with increased heat tolerance. In contrast, Arabidopsis plants overexpressing At-NF-YA2, or those expressing a non-cleavable At-NF-YA2 form (miR169d-resistant At-NF-YA2) as well as plants inhibited for At-miRNA169d regulation (miR169d mimic plants) were more sensitive to heat stress, highlighting NF-YA as negative regulator of heat tolerance. Furthermore, post-transcriptional cleavage of NF-YA by elevated miR169 levels resulted in alleviating the repression of heat stress effectors HSFA7a/b in tomato and Arabidopsis revealing a retroactive control of HSFs by the miR169:NF-YA node. Hence, a regulatory feedback loop involving HSFs, miR169s and NF-YAs plays a critical role in the regulation of heat stress response in tomato and Arabidopsis plants.

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