Leaf structure and ultrastructure changes induced by heat stress and drought during seed filling in field-grown soybean and their relationship with grain yield

Heat stress during reproductive and grain filling phases adversely affects the growth of cereals through reduction in grain’s number and size. However, exogenous application of antioxidants, plant growth regulators and osmoprotectants may be helpful to minimize these heat induced yield losses in cereals. This two year study was conducted to evaluate the role of exogenous application of ascorbic acid (AsA), salicylic acid (SA) and hydrogen peroxide (H2O2) applied through seed priming or foliar spray on biochemical, physiological, morphological and yield related traits, grain yield and quality of late spring sown hybrid maize. The experiment was conducted in the spring season of 2007 and 2008. We observed that application of AsA, SA and H2O2 applied through seed priming or foliar spray improved the physiological, biochemical, morphological and yield related traits, grain yield and grain quality of late spring sown maize in both years. In both years, we observed higher superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD) activity in the plants where AsA, SA and H2O2were applied through seed priming or foliar spray than control. Membrane stability index (MSI), relative water contents (RWC), chlorophyll contents, grain yield and grain oil contents were also improved by exogenous application of AsA, SA and H2O2 in both years. Seed priming of AsA, SA and H2O2was equally effective as the foliar application. In conclusion, seed priming with AsA, SA and H2O2 may be opted to lessen the heat induced yield losses in late sown spring hybrid maize. Heat tolerance induced by ASA, SA and H2O2 may be attributed to increase in antioxidant activities and MSI which maintained RWC and chlorophyll contents in maize resulting in better grain yield in heat stress conditions.

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Effect of Heat Stress on Inter-relationship of Physiological and Biochemical Traits with Grain Yield in Wheat (Triticum aestivum L.)

Current Journal of Applied Science and Technology ◽

10.9734/cjast/2020/v39i1930786 ◽

2020 ◽

pp. 19-29

Author(s):

Amrita Kumari ◽

R. D. Ranjan ◽

Chandan Roy ◽

Awadesh Kumar Pal ◽

S. Kumar

Keyword(s):

Heat Stress ◽

Grain Yield ◽

Flag Leaf ◽

Grain Filling ◽

Triticum Aestivum L ◽

Seedling Stage ◽

Biochemical Traits ◽

Highly Correlated ◽

Complex Phenomena ◽

Physiological And Biochemical

Heat stress, particularly the stress appears at the time of flowering to grain filling stages causing severe yield loss in wheat. Heat tolerance is complex phenomena that include adjustment in morphological, physiological and biochemical traits of the crop. Present investigation was carried out to understand the effect of terminal heat stress on different traits of wheat. The experiment was conducted in three dates of sowing as timely sown, late sown and very late sown to expose the crop to heat stress at later stages of the crop growth. Significant genetic variations for all the traits evaluated under three conditions indicated the presence of variability for the traits. Trait association analysis revealed that flag leaf chlorophyll content and MSI at seedling stage; MDA at reproductive stage had direct relationship with grain yield. While under very late sown condition MDA and RWC at seedling stages were found to be highly correlated with grain yield. It indicates that MDA, RWC at seedling stage and days to booting, days to milking plays important role in very late sown condition that can be used as selection criteria in breeding programme.

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Genetic Dissection of Grain Yield Component Traits Under High Nighttime Temperature Stress in a Rice Diversity Panel

Frontiers in Plant Science ◽

10.3389/fpls.2021.712167 ◽

2021 ◽

Vol 12 ◽

Author(s):

Anuj Kumar ◽

Chirag Gupta ◽

Julie Thomas ◽

Andy Pereira

Keyword(s):

Heat Stress ◽

Grain Yield ◽

Candidate Genes ◽

Significant Snps ◽

The United States ◽

Yield Component ◽

Reproductive Stage ◽

Venn Diagram ◽

Rice Grain ◽

Diversity Panel

To dissect the genetic complexity of rice grain yield (GY) and quality in response to heat stress at the reproductive stage, a diverse panel of 190 rice accessions in the United States Department of Agriculture (USDA) rice mini-core collection (URMC) diversity panel were treated with high nighttime temperature (HNT) stress at the reproductive stage of panicle initiation. The quantifiable yield component response traits were then measured. The traits, panicle length (PL), and number of spikelets per panicle (NSP) were evaluated in subsets of the panel comprising the rice subspecies Oryza sativa ssp. Indica and ssp. Japonica. Under HNT stress, the Japonica ssp. exhibited lower reductions in PL and NSP and a higher level of genetic variation compared with the other subpopulations. Whole genome sequencing identified 6.5 million single nucleotide polymorphisms (SNPs) that were used for the genome-wide association studies (GWASs) of the PL and NSP traits. The GWAS analysis in the Combined, Indica, and Japonica populations under HNT stress identified 83, 60, and 803 highly significant SNPs associated with PL, compared to the 30, 30, and 11 highly significant SNPs associated with NSP. Among these trait-associated SNPs, 140 were coincident with genomic regions previously reported for major GY component quantitative trait loci (QTLs) under heat stress. Using extents of linkage disequilibrium in the rice populations, Venn diagram analysis showed that the highest number of putative candidate genes were identified in the Japonica population, with 20 putative candidate genes being common in the Combined, Indica and Japonica populations. Network analysis of the genes linked to significant SNPs associated with PL and NSP identified modules that were involved in primary and secondary metabolisms. The findings in this study could be useful to understand the pathways/mechanisms involved in rice GY and its components under HNT stress for the acceleration of rice-breeding programs and further functional analysis by molecular geneticists.

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

Functional Plant Biology ◽

10.1071/fp19246 ◽

2020 ◽

Vol 47 (5) ◽

pp. 440 ◽

Cited By ~ 4

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.

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

Australian Journal of Crop Science ◽

10.21475/ajcs.19.13.04.p1448 ◽

2019 ◽

Vol 13 ((04) 2019) ◽

pp. 536-545 ◽

Cited By ~ 2

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.

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Evaluation of Spring Wheat Genotypes (Triticum Aestivum L.) for Heat Stress Tolerance Using Different Stress Tolerance Indices

Cercetari Agronomice in Moldova ◽

10.1515/cerce-2015-0004 ◽

2015 ◽

Vol 47 (4) ◽

pp. 49-63 ◽

Cited By ~ 5

Author(s):

A.A. Khan ◽

M.R. Kabir

Keyword(s):

Heat Stress ◽

Grain Yield ◽

Stress Tolerance ◽

Spring Wheat ◽

Grain Filling ◽

Filling Rate ◽

Wheat Genotypes ◽

Grain Filling Rate ◽

Heat Stress Tolerance ◽

Late Sowing

Abstract Twenty five spring wheat genotypes were evaluated for terminal heat stress tolerance in field environments in the Agro Ecological Zone-11 of Bangladesh, during 2009-2010 cropping season. The experiments were conducted at Wheat Research Centre, Bangladesh Agricultural Research Institute, using randomized block design with three replicates under non-stress (optimum sowing) and stress (late sowing) conditions. Seven selection indices for stress tolerance including mean productivity (MP), geometric mean productivity (GMP), tolerance (TOL), yield index (YI), yield stability index (YSI), stress tolerance index (STI) and stress susceptibility index (SSI) were calculated based on grain yield of wheat under optimum and late sowing conditions. The results revealed significant variations due to genotypes for all characters in two sowing conditions. Principal component analysis revealed that the first PCA explained 0.64 of the variation with MP, GMP, YI and STI. Using MP, GMP, YI and STI, the genotypes G-05 and G-22 were found to be the best genotypes with relatively high yield and suitable for both optimum and late heat stressed conditions. The indices SSI, YSI and TOL could be useful parameters in discriminating the tolerant genotypes (G-12, G-13, and G-14) that might be recommended for heat stressed conditions. It is also concluded from the present studies that biomass, grain filling rate and spikes number m-2 are suitable for selecting the best genotypes under optimum and late sowing conditions because these parameters are highly correlated with MP, GMP, YI and STI. However, high ground cover with long pre heading stage and having high grain filling rate would made a genotype tolerant to late heat to attain a high grain yield in wheat.

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