Terminal Heat Stress and its Effects in Wheat Crop: A Review

ABSTRACTWheat crop in Nepal faces terminal heat stress which accelerates the gain filling rate and shortens the filling period which leads to reduced grain weight, size, number, quality that is yield loss. For minimization of this loss, genotypic selection of high yielding lines should be performed understanding the gene-environment interaction. With the view to obtain a high yielding line with stable performance across the environments an experiment was conducted using 18 elite wheat line and 2 check varieties in alpha lattice design (2 replication and 5 blocks per replication) in different environments viz. irrigated and terminal heat stressed environment. The analysis of variance revealed that genotype, environment and their interaction had highly significant effect on the yield. Furthermore, which-won–where model indicated specific adaptation of elite lines NL-1179, NL-1420, BL-4407, NL-1368 to irrigated environment and BL-4919 and NL-1350 to terminal heat-stressed environment. Similarly, Mean-versus-stability study indicated that elite line BL-4407, NL-1368, BL-4919, NL-1350 and NL-1420 had above average yield and higher stability whereas elite lines Gautam, NL-1412, NL-1376, NL-1387, NL-1404 and N-1381 had below average yield and lower stability. Also, ranking elite lines biplot, PCA1 explaining 73.6% and PCA2 explaining 26.4% of the interaction effect, showed the rank of elite line, NL-1420 > NL-1368> NL-1350 > other lines, close to ideal line. From these findings, NL-1420 with high yield and stability can be recommended across both the environment while NL-1179 is adapted specifically for irrigated and NL-1350 adapted specifically for terminal heat-stressed environment.

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Exogenous application of silicon improves the performance of wheat under terminal heat stress by triggering physio-biochemical mechanisms

Scientific Reports ◽

10.1038/s41598-021-02594-4 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Talha Mustafa ◽

Abdul Sattar ◽

Ahmad Sher ◽

Sami Ul-Allah ◽

Muhammad Ijaz ◽

...

Keyword(s):

Heat Stress ◽

Chlorophyll A ◽

Growth Phase ◽

Foliar Application ◽

Soluble Sugar ◽

Wheat Crop ◽

Chlorophyll Contents ◽

Terminal Heat Stress ◽

Biochemical Components ◽

Heading Stage

AbstractDue to climate change, temperature in late February and early March raised up which cause heat stress at reproductive stage (terminal growth phase of wheat crop) which has become the major causative factor towards low wheat production in arid and semiarid regions. Therefore; strategies need to be adopted for improving terminal heat stress tolerance in wheat. In this study, we assessed whether foliar application of silicon (Si) (2 and 4 mM) at terminal growth phase i.e. heading stage of wheat imposed to heat stress (37 ± 2 °C) under polythene tunnel could improve the performance of wheat. Results of the study revealed that heat stress significantly reduced the photosynthetic pigments (chlorophyll a, b and a + b and carotenoids) leading to a lower grain yield. However, a 4 mM Si application (foliar applied) at heading stage prominently increased the chlorophyll a, b and a + b and carotenoids of flag leaf by improving the activities of enzymatic antioxidants (catalase, peroxidase and superoxide dismutase) and osmoprotectants (soluble sugar protein and proline) under terminal heat stress. Improvements in the performance of wheat (chlorophyll contents, carotenoids, soluble sugar and proteins and proline and yield) with foliar application of Si were also observed under control conditions. Correlation analysis revealed strong association (r > 0.90) of chlorophyll contents and carotenoids with grain and biological yield. Negative correlation (−0.81 < r > −0.63) of physio-biochemical components (antioxidants, proline, soluble sugars and proteins) with yield revealed that under heat stress these components produced in more quantities to alleviate the effects of heat, and Si application also improved these physio biochemical components. In crux, foliar application of Si alleviates the losses in the performance of wheat caused by terminal heat stress by improving the antioxidant mechanism and production of osmoprotectants.

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Evaluation of Triticum durum–Aegilops tauschii derived primary synthetics as potential sources of heat stress tolerance for wheat improvement

Plant Genetic Resources ◽

10.1017/s1479262121000113 ◽

2021 ◽

Vol 19 (1) ◽

pp. 74-89

Author(s):

Amandeep Kaur ◽

Parveen Chhuneja ◽

Puja Srivastava ◽

Kuldeep Singh ◽

Satinder Kaur

Keyword(s):

Heat Stress ◽

Stress Tolerance ◽

Hexaploid Wheat ◽

Aegilops Tauschii ◽

Grain Filling ◽

World Population ◽

Potential Candidate ◽

Terminal Heat Stress ◽

Heat Stress Tolerance ◽

The Impact

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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