Quantifying the Impact of Heat Stress on Pollen Germination, Seed Set, and Grain Filling in Spring Wheat

AbstractAddressing the impact of heat stress during flowering and grain filling is critical to sustaining wheat productivity to meet a steadily increasing demand from a rapidly growing world population. Crop wild progenitor species of wheat possess a wealth of genetic diversity for several biotic and abiotic stresses, and morphological traits and can serve as valuable donors. The transfer of useful variation from the diploid progenitor, Aegilops tauschii, to hexaploid wheat can be done through the generation of synthetic hexaploid wheat (SHW). The present study targeted the identification of potential primary SHWs to introduce new genetic variability for heat stress tolerance. Selected SHWs were screened for different yield-associated traits along with three advanced breeding lines and durum parents as checks for assessing terminal heat stress tolerance under timely and late sown conditions for two consecutive seasons. Heat tolerance index based on the number of productive tillers and thousand grain weight indicated that three synthetics, syn9809 (64.32, 78.80), syn14128 (50.30, 78.28) and syn14135 (58.16, 76.03), were able to endure terminal heat stress better than other SHWs as well as checks. One of these synthetics, syn14128, recorded a minimum reduction in thousand kernel weight (21%), chlorophyll content (2.56%), grain width (1.07%) despite minimum grain-filling duration (36.15 d) and has been selected as a potential candidate for introducing the terminal heat stress tolerance in wheat breeding programmes. Breeding efforts using these candidate donors will help develop lines with a higher potential to express the desired heat stress-tolerant phenotype under field conditions.

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Spikelet fertility and heat shock transcription factor (Hsf) gene responses to heat stress in tolerant and susceptible rice (Oryza sativa L.) genotypes

The Journal of Agricultural Science ◽

10.1017/s002185961900056x ◽

2019 ◽

Vol 157 (04) ◽

pp. 283-299 ◽

Cited By ~ 3

Author(s):

C. Malumpong ◽

S. Cheabu ◽

C. Mongkolsiriwatana ◽

W. Detpittayanan ◽

A. Vanavichit

Keyword(s):

Heat Stress ◽

Pollen Germination ◽

Seed Set ◽

Oryza Sativa L ◽

Flag Leaf ◽

Pollen Viability ◽

Spikelet Fertility ◽

Anther Dehiscence ◽

Spikelet Sterility ◽

Plant Parts

AbstractThe reproductive stage of rice is the most sensitive to heat stress, which can lead to spikelet sterility. Thus, heat-tolerant and heat-susceptible genotypes were used to investigate their differences in terms of phenotypic responses and expression changes of Hsf genes at the pre-flowering stage under heat stress. Results clearly showed that panicles had the highest temperature compared with other plant parts under both natural and heated conditions. However, the temperatures of tolerant and susceptible genotypes were not significantly different. In terms of spikelet fertility, the tolerant lines M9962 and M7988 had high seed set because their anther dehiscence, pollen viability and pollen germination were only slightly affected. In contrast, the susceptible line Sinlek showed severe effects at all steps of fertilization, and the pollen viability of M7766 was slightly affected under heat stress but was more affected in terms of anther dehiscence and pollen germination. Both susceptible lines showed dramatically decreased seed set. In addition, the expression of six HsfA genes in the flag leaves and spikelets at the R2 stage of plants under heat stress showed different responses. Notably, expression of the HsfA2a gene was predominantly upregulated in the flag leaf and spikelets under heat stress in M9962. Therefore, it can be concluded that heat stress has severe effects on the stamen, and that different genotypes have different susceptibilities to heat stress.

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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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Heat stress in grain legumes during reproductive and grain-filling phases

Crop and Pasture Science ◽

10.1071/cp17012 ◽

2017 ◽

Vol 68 (11) ◽

pp. 985 ◽

Cited By ~ 18

Author(s):

Muhammad Farooq ◽

Faisal Nadeem ◽

Nirmali Gogoi ◽

Aman Ullah ◽

Salem S. Alghamdi ◽

...

Keyword(s):

Heat Stress ◽

High Temperature ◽

Grain Yield ◽

Leaf Senescence ◽

Management Strategies ◽

Substantial Reduction ◽

Grain Filling ◽

Grain Legumes ◽

Grain Legume ◽

The Impact

Thermal stress during reproductive development and grain-filling phases is a serious threat to the quality and productivity of grain legumes. The optimum temperature range for grain legume crops is 10−36°C, above which severe losses in grain yield can occur. Various climatic models have simulated that the temperature near the earth’s surface will increase (by up to 4°C) by the end of this century, which will intensify the chances of heat stress in crop plants. The magnitude of damage or injury posed by a high-temperature stress mainly depends on the defence response of the crop and the specific growth stage of the crop at the time of exposure to the high temperature. Heat stress affects grain development in grain legumes because it disintegrates the tapetum layer, which reduces nutrient supply to microspores leading to premature anther dehiscence; hampers the synthesis and distribution of carbohydrates to grain, curtailing the grain-filling duration leading to low grain weight; induces poor pod development and fractured embryos; all of which ultimately reduce grain yield. The most prominent effects of heat stress include a substantial reduction in net photosynthetic rate, disintegration of photosynthetic apparatus and increased leaf senescence. To curb the catastrophic effect of heat stress, it is important to improve heat tolerance in grain legumes through improved breeding and genetic engineering tools and crop management strategies. In this review, we discuss the impact of heat stress on leaf senescence, photosynthetic machinery, assimilate translocation, water relations, grain quality and development processes. Furthermore, innovative breeding, genetic, molecular and management strategies are discussed to improve the tolerance against heat stress in grain legumes.

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Heat Stress during Flowering Affects Time of Day of Flowering, Seed Set, and Grain Quality in Spring Wheat

Crop Science ◽

10.2135/cropsci2017.04.0221 ◽

2018 ◽

Vol 58 (1) ◽

pp. 380-392 ◽

Cited By ~ 21

Author(s):

Sun Aiqing ◽

Impa Somayanda ◽

Sunoj Valiaparambil Sebastian ◽

Kanwardeep Singh ◽

Kulvinder Gill ◽

...

Keyword(s):

Heat Stress ◽

Spring Wheat ◽

Grain Quality ◽

Seed Set ◽

Time Of Day

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DIFFERENTIAL RESPONSE OF WHEAT GENOTYPES TO HEAT STRESS DURING GRAIN FILLING

Experimental Agriculture ◽

10.1017/s0014479718000406 ◽

2018 ◽

Vol 55 (5) ◽

pp. 818-827 ◽

Cited By ~ 2

Author(s):

PARIMALAN RANGAN ◽

AGNELO FURTADO ◽

ROBERT HENRY

Keyword(s):

Heat Stress ◽

Agronomic Traits ◽

Grain Filling ◽

Heat Stress Response ◽

Global Food Security ◽

Temperature And Precipitation ◽

Global Agriculture ◽

Grain Width ◽

Origin Of Agriculture ◽

The Impact

SUMMARYClimatic change affects global agriculture and is a severe threat to global food security due to variability of the three factors measuring climate change (CO2, temperature and precipitation) with temperature being the most crucial one. Wheat is severely affected by high temperatures with reproductive and grain-filling phases being most sensitive, impacting grain number, size and weight. Seed size and weight are the key agronomic traits subjected to artificial selection and involved in the domestication process since the origin of agriculture. Three genotypes Banks, EGA Gregory and Fang-60 with the latter known to be heat tolerant were grown under glass house conditions and subjected to heat stress for 3 days during early- (11–14 dpa – days post anthesis) and late- (27–30 dpa) grain filling stages in a mutually exclusive fashion. The impact of heat stress during early- and late- grain filling on the four major grain characteristics, thousand grain weight (TGW), grain length, grain width and grain thickness was assessed. The tolerant genotype Fang-60 exhibited significantly higher TGW during early-grain filling heat stress than the control possibly due to an ability to exploit the accelerated release of fertilizer under high temperature. Banks and EGA Gregory were moderately tolerant to susceptible to heat stress, respectively, at early- and late-grain filling with Fang-60 being tolerant to both early- and late- grain filling heat stress. This study confirms the availability of significant genetic variation in heat stress response in wheat that might be exploited to adapt wheat to higher growth temperatures.

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The impact of water deficit and heat stress combination on the molecular response, physiology and seed production of soybean

10.1101/2020.09.30.320341 ◽

2020 ◽

Author(s):

Itay Cohen ◽

Sara I. Zandalinas ◽

Felix B. Fritschi ◽

Soham Sengupta ◽

Yosef Fichman ◽

...

Keyword(s):

Heat Stress ◽

Water Deficit ◽

Seed Production ◽

Pollen Germination ◽

Plant Introduction ◽

Molecular Response ◽

Yield Production ◽

Soybean Genotypes ◽

Drought And Heat Stress ◽

The Impact

AbstractA combination of drought and heat stress, occurring at the vegetative or reproductive growth phase of many different crops, can have a devastating impact on yield. In soybean (Glycine max), a considerable effort has been made to develop genotypes with enhanced yield production under conditions of drought or heat stress. However, how these genotypes perform in terms of growth, physiological responses and most importantly seed production, under conditions of drought and heat combination is mostly unknown. Here, we studied the impact of water deficit and heat stress combination on the physiology, seed production and yield per plant of two soybean genotypes, Magellan and Plant Introduction (PI) 548313, that differ in their reproductive responses to heat stress. Our findings reveal that although PI 548313 produced more seeds than Magellan under conditions of heat stress, under conditions of water deficit and heat stress combination its seed production decreased. Because number of flowers and pollen germination of PI 548313 remained high under heat or water deficit and heat combination, the reduced seed production exhibited by PI 548313 under the stress combination could be a result of processes that occur at the stigma, ovaries and/or other parts of the flower following pollen germination.HighlightTolerance to heat stress was found not to confer tolerance to a combination of water deficit and heat stress in soybean, highlighting the need for breeding strategies targeting the stress combination.

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The Response of Iranian Spring Wheat Cultivars to Heat Stress at Anthesis and Grain Filling Stages

Journal of Crop Breeding ◽

10.29252/jcb.12.33.102 ◽

2020 ◽

Vol 12 (33) ◽

pp. 102-109

Author(s):

Ahmad rezaeizadeh ◽

valiollah Mohammadi ◽

mohammadreza siahpoosh ◽

ali ahmadi ◽

◽

...

Keyword(s):

Heat Stress ◽

Spring Wheat ◽

Grain Filling ◽

Wheat Cultivars

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Increasing Heat Tolerance in Wheat to Counteract Recent and Projected Increases in Heat Stress

Proceedings ◽

10.3390/proceedings2019036132 ◽

2020 ◽

Vol 36 (1) ◽

pp. 132

Author(s):

Najeeb Ullah ◽

Behnam Ababaei ◽

Karine Chenu

Keyword(s):

Grain Size ◽

Heat Stress ◽

Leaf Senescence ◽

Recombinant Inbred Lines ◽

Grain Filling ◽

Heat Effects ◽

Heat Shocks ◽

Tolerant Line ◽

The Impact ◽

Leaf Greenness

The frequency of heat shocks during grain filling of wheat crops across the Australian wheatbelt has significantly increased over the last 30 years. These post-flowering heat events significantly reduce wheat yields with a relatively greater impact on grain size than grain number. A controlled environment study was conducted to assess the impact of post-flowering heat shocks on wheat recombinant inbred lines SB062 and SB003. Plants were submitted to 7-day heat shocks (33/21 °C day/night temperature) at different periods during grain filling. Heat shocks significantly accelerated leaf senescence, with a greater impact on older leaves and for mid post-flowering stresses. Overall, the tolerant line (SB062) could maintain leaf greenness longer than the sensitive line (SB003), especially when submitted to heat stress. Further, heat shocks during early-to-mid grain filling reduced the grain size and weight. While the impact on developing grains was significant in SB003, no significant effect of post-flowering heat was observed on leaf senescence nor on grain size in the tolerant line SB062. Delayed leaf senescence appeared to play a role in maintaining grain size under heat stress. The research findings will assist improving crop models for post-flowering heat effects and developing techniques for screening heat tolerant wheat lines. Increased post-flowering assimilate production through sustained leaf greenness could improve the performance of wheat crops in increasingly warmer environments.

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Evaluation of Physiological and Morphological Traits for Improving Spring Wheat Adaptation to Terminal Heat Stress

Plants ◽

10.3390/plants10030455 ◽

2021 ◽

Vol 10 (3) ◽

pp. 455

Author(s):

Hafeez ur Rehman ◽

Absaar Tariq ◽

Imran Ashraf ◽

Mukhtar Ahmed ◽

Adele Muscolo ◽

...

Keyword(s):

Heat Stress ◽

Grain Yield ◽

Spring Wheat ◽

Grain Filling ◽

Adaptive Traits ◽

Wheat Genotypes ◽

Terminal Heat Stress ◽

Early Maturing ◽

Heat Tolerant ◽

Late Sowing

Wheat crop experiences high temperature stress during flowering and grain-filling stages, which is termed as “terminal heat stress”. Characterizing genotypes for adaptive traits could increase their selection for better performance under terminal heat stress. The present study evaluated the morpho-physiological traits of two spring wheat cultivars (Millet-11, Punjab-11) and two advanced lines (V-07096, V-10110) exposed to terminal heat stress under late sowing. Early maturing Millet-11 was used as heat-tolerant control. Late sowing reduced spike length (13%), number of grains per spike (10%), 1000-grain weight (13%) and biological yield (15–20%) compared to timely sowing. Nonetheless, higher number of productive tillers per plant (19–20%) and grain yield (9%) were recorded under late sowing. Advanced lines and genotype Punjab-11 had delayed maturity and better agronomic performance than early maturing heat-tolerant Millet-11. Advanced lines expressed reduced canopy temperature during grain filling and high leaf chlorophyll a (20%) and b (71–125%) contents during anthesis under late sowing. All wheat genotypes expressed improved stem water-soluble carbohydrates under terminal heat stress that were highest for heat-tolerant Millet-11 genotype during anthesis. Improved grain yield was associated with the highest chlorophyll contents showing stay green characteristics with maintenance of high photosynthetic rates and cooler canopies under late sowing. The results revealed that advanced lines and Punjab-11 with heat adaptive traits could be promising source for further use in the selection of heat-tolerant wheat genotypes.

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