Performance of Yield and Stability of Advanced Wheat Genotypes under Heat Stress Environments of the Indo-Gangetic Plains

Many endurance athletes perform specific blocks of training in hot environments in “heat stress training camps.” It is not known if physiological threshold heart rates measured in temperate conditions are reflective of those under moderate environmental heat stress. A total of 16 endurance-trained cyclists and triathletes performed incremental exercise assessments in 18°C and 35°C (both 60% relative humidity) to determine heart rates at absolute blood lactate and ventilatory thresholds. Heart rate at fixed blood lactate concentrations of 2, 3, and 4 mmol·L−1 and ventilatory thresholds were not significantly different between environments (P > .05), despite significant heat stress-induced reductions in power output of approximately 10% to 17% (P < .05, effect size = 0.65–1.15). The coefficient of variation for heart rate at these blood lactate concentrations (1.4%−2.9%) and ventilatory thresholds (2.3%−2.7%) between conditions was low, with significant strong positive correlations between measurements in the 2 environments (r = .92–.95, P < .05). These data indicate heart rates measured at physiological thresholds in temperate environments are reflective of measurements taken under moderate environmental heat stress. Therefore, endurance athletes embarking on heat stress training camps can use heart rate–based thresholds ascertained in temperate environments to prescribe training under moderate environmental heat stress.

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Raising productivity of cereal crops in dry and heat stress environments remains a breeding challenge.

CAB Reviews Perspectives in Agriculture Veterinary Science Nutrition and Natural Resources ◽

10.1079/pavsnnr202116008 ◽

2021 ◽

Vol 16 (008) ◽

Author(s):

Sangam L. Dwivedi

Keyword(s):

Heat Stress ◽

Agricultural Production ◽

Green Revolution ◽

Cereal Crops ◽

Plant Genes ◽

Stress Environments

Abstract 'Green Revolution' genes have led to the release of input-responsive cultivars, resulting in multifold productivity increases in rice and wheat. Declining precipitation, increased intensity of drought and rising temperature are casting uncertainty over agricultural production. As noted in this mini review, plant genes when over-expressed allow cereals to produce grains in drought- and heat-prone sites.

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Heat stress effects on source–sink relationships and metabolome dynamics in wheat

Journal of Experimental Botany ◽

10.1093/jxb/erz296 ◽

2019 ◽

Vol 71 (2) ◽

pp. 543-554 ◽

Cited By ~ 10

Author(s):

Mostafa Abdelrahman ◽

David J Burritt ◽

Aarti Gupta ◽

Hisashi Tsujimoto ◽

Lam-Son Phan Tran

Keyword(s):

Heat Stress ◽

High Temperature ◽

Negative Impact ◽

Grain Filling ◽

Wheat Breeding ◽

Wheat Genotypes ◽

Stress Effects ◽

Wide Range ◽

High Yields ◽

Source Sink

Abstract Crops such as wheat (Triticum spp.) are predicted to face more frequent exposures to heat stress as a result of climate change. Increasing the yield and sustainability of yield under such stressful conditions has long been a major target of wheat breeding, and this goal is becoming increasingly urgent as the global population increases. Exposure of wheat plants in their reproductive or grain-filling stage to high temperature affects the duration and rate of grain filling, and hence has a negative impact on wheat productivity. Therefore, understanding the plasticity of the response to heat stress that exists between wheat genotypes, especially in source–sink relationships at the reproductive and grain-filling stages, is critical for the selection of germplasm that can maintain high yields under heat stress. A broad understanding of metabolic dynamics and the relationships between metabolism and heat tolerance is required in order to achieve this goal. Here, we review the current literature concerning the effects of heat stress on sink–source relationships in a wide range of wheat genotypes, and highlight the current metabolomic approaches that are used to investigate high temperature responses in wheat.

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

International Journal of Climate Change Strategies and Management ◽

10.1108/ijccsm-05-2018-0048 ◽

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

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

Plant Genetic Resources ◽

10.1017/s1479262116000241 ◽

2016 ◽

Vol 15 (6) ◽

pp. 539-547 ◽

Cited By ~ 5

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.

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