Combating Heat Stress in Late Sown Wheat through Pre-Sowing Seed Priming

Wheat, a cereal grain, has been a cornerstone of human civilization for thousands of years. Its importance goes beyond basic survival because it is intricately linked to history, culture, and international economies. The domestication of wheat 10,000 years ago represents a major turning point in human civilization and is therefore a historically significant staple crop (Singh et al., 2023). A notable source of vegetable protein in human diets, wheat contributes roughly 13% of its protein content. It is primarily composed of gluten, which makes up 75–80% of the protein in wheat. Wheat also contributes significantly to carbohydrates (71%). Whole grains, such as wheat, are a rich source of dietary fiber and other essential nutrients (Srivastava et al., 2023). Bangladesh's agricultural policies now place a strong emphasis on wheat because of the realization that crop diversification is essential for ensuring food security. Currently, Bangladesh cultivates 1.23 million tons of wheat on 0.34 million hectares of land, producing an average of 3.63 tons per hectare (BBS, 2022). Bangladesh’s modest size and limited climatic diversity make it a less diverse tropical nation than other countries with more varied climates or temperate climates. As a result, Bangladesh produces less wheat on average compared to other countries with diversified climatic conditions or temperate climates (Islam et al., 2023). Stresses from the environment, such as low soil moisture, high temperatures, and inadequate light, can negatively impact wheat growth and yield. Of these, high temperature is the most important (Modarresi et al., 2010; Trnka et al., 2004). Heat stress affects over 50 countries that annually import more than 20 million tons of wheat. This stress is characterized by a mean daily temperature exceeding 17.5 °C during the coolest month of the season and persists throughout the entire wheat growth cycle (Modarresi et al., 2010). When considering the various factors that affect the country's low wheat yield, the date of sowing holds the most tremendous significance.

The precise environmental conditions that every crop variety requires to reach its maximum potential can be helped by choosing the appropriate sowing date. The optimal time to plant wheat in Bangladesh is from mid-November to the first week of December. There are several reasons why the sowing date of wheat is delayed, including inadequate irrigation water, excessive moisture or waterlogging conditions from flooding, and the late harvesting of Kharif crops, particularly transplanting Aman rice. Crucial stages for increasing wheat yield are root development, germination, and grain development. Nevertheless, early sowing severely hinders root development because plants suffer from drought stress at that time, and late sowing hinders germination and grain development due to foggy conditions and dew drops, which affect the development of germination and grain development in wheat (Tahir et al., 2009). Maximizing grain and straw output hinges on prioritizing the tillering phase. This critical stage directly influences tiller count, spike formation, the number of grains per spike, and individual grain weight. Furthermore, timely planting remains a non-negotiable factor in achieving optimal results (Qasim et al., 2008). Wheat production in Bangladesh faces challenges primarily due to environmental limitations, including delayed planting and a brief winter season (Ahmed et al., 2019).

Wheat typically experiences two distinct types of heat stress: continuous and terminal heat stress. “Continuous heat stress” persists throughout the entire wheat growth season, from sowing to maturity. In contrast, “terminal heat stress” occurs during the reproductive growth stages, specifically from heading to maturity (Reynolds et al., 2001). Elevated temperatures accelerate the development of the spike and decrease the number of grains and spikelets within each spike (Farooq et al., 2011). The worldwide impact of heat stress on wheat is estimated to be 36 million hectares, with 40% of the crop experiencing terminal heat stress (Kumar et al., 2023; Reynolds et al., 2010). In tropical and subtropical regions, however, 25–30 million hectares of wheat are vulnerable to yield loss due to heat stress (including China, Bangladesh, Nepal, India, Pakistan, Ethiopia, Sudan, Egypt, and North Africa). Global warming projections and current trends indicate that this area is expected to experience significant increases. According to reports, the yield drop caused by high temperatures in developing countries is approximately 29%. According to the climate scenario for the future, wheat production is expected to decline significantly due to rising temperatures (Ortiz et al., 2008). Bangladesh's wheat yield would drop by 68% with every 4 °C increase in temperature (Acharjee and Shariot-Ullah, 2021). Moreover, a doubling of temperature and atmospheric CO₂ concentration would result in a 31% decline in wheat yield worldwide. Under terminal heat stress, the lengthening of the grain-filling period results in smaller grains and a lower grain spike^-1 than in a suitable planting crop (Farhad et al., 2023).

Utilizing a variety of agronomic management strategies can lessen the detrimental effects of high temperatures on wheat yield. Nonetheless, wheat's sensitivity to high temperatures can be reduced by various physiological techniques. One of these low-cost techniques for encouraging crop stand establishment is seed priming (Farooq et al., 2006). The technique known as “seed priming” involves controlling the hydration process inside seeds, re-drying them, and triggering numerous physiological processes related to the initial stages of germination, thereby preparing them for radical protrusion, which suspends the seeds in the lag phase (Paparella et al., 2015). Before distributing seeds, a seed priming treatment is carried out. This means that seeds must be adequately hydrated to permit the occurrence of metabolic processes before germination while inhibiting the formation of radicles (Rehman et al., 2011; Nascimento et al., 2013). Prime seeds may germinate more quickly due to a variety of factors, including increased activity of degrading enzymes such as amylase, RNA and DNA synthesis, the amount of ATP, and the presence of mitochondria (Afzal et al., 2002). Due to their many benefits, primed seeds are also more beneficial. Increased metabolic events can trigger the germination of dormant seeds (Soleimanzadeh, 2013), allowing for early flowering and maturity, as well as early reproductive organ growth and improved resistance to abiotic stresses (Maasoumeh and Mohammad, 2014) and soil-borne pathogens such as Rhizoctonia solani, Fusarium spp., and Sclerotium rolfsii (Rafi et al., 2015).

Considering that Bangladesh's population is growing rapidly, and that the nation needs wheat daily. Further research endeavors should focus more on enhancing wheat yield under heat stress conditions by developing heat-tolerant cultivars and efficient techniques, such as seed priming. In-depth research on how different seed priming techniques affect wheat development and yield under late-sowing conditions has been limited. Keeping this in mind, this present research work was designed to identify the most suitable priming technique for enhancing the growth and yield of late-sown wheat under high-temperature stress.

Experimental sites

A field trial was carried out at the Agronomy Field Laboratory of Bangladesh Agricultural University (24°43'12"N 90°25'37"E and 18.6 m above sea level) from November 2022 to March 2023. The area belongs to the non-calcareous, dark gray floodplain soil of the Old Brahmaputra Floodplain agroecological zone (AEZ 9). The land had a silty-loam texture, was medium to high in elevation, and was well-drained. At pH 6.65, with 1.21% of organic matter, 0.12% of total nitrogen, 26.07 ppm of available phosphorus, 0.15 me % of exchangeable potassium, and a moderate overall fertility level, the soil in the experimental field was essentially neutral in reaction. The experimental site is located in a humid, sub-tropical monsoon climate. Table 1 provides information on the pattern of rainfall, sunlight hours, temperature fluctuations, and relative humidity over the research period, and also shows the maximum, minimum, and average temperatures during the experimental period.

Table 1. Weather data from November 2022 to March 2023 at the experimental site during the growing season of wheat

Source: Weather Yard, Department of Irrigation and Water Management, Bangladesh Agricultural University, Mymensingh.

Treatments and design

Two factors were involved in the experiment, Factor A: sowing date and Factor B: priming agents. Three dates were selected for sowing, viz., D₁: optimum sowing (30 November), D₂: late sowing (15 December), and D₃: very late sowing (30 December). The experiment employed only laboratory-grade priming agents manufactured by MERCK, India. Six conditions were created by using five priming agents such as a) no priming (P₁) (b) hydro priming(P₂) (c) priming with 20000 ppm CaCl₂ (P₃) (d) priming with 20000 ppm KCl (P₄) (e) priming with 15000 ppm KNO₃ (P₅) and (f) priming with 40000 ppm Mannitol (C₆H₁₄O₆) (P₆). A split-plot design with three replications was used to set up the experiment, resulting in a total of 54 plots (18 × 3). The date of sowing was assigned in the main plots, while seed priming practices were assigned in the sub-plots. Plot dimensions were 2.5 m × 2.0 m. The distances between plots and blocks were 0.5 and 1.0 meters, respectively.

Plant material

BARI Gom-33 is a Zn-enriched and wheat blast-resistant variety with weaker glaucosity in the spike, released by the Wheat Research Centre, Bangladesh Agricultural Research Institute (BARI), Dinajpur, in 2017 [this research center is currently renamed as the Bangladesh Wheat and Maize Research Institute (BWMRI)]. The variety has a dark green stem and leaf. It needs roughly 60–65 days for heading and 110–115 days for physiological maturation. Tillers are semi-erect during heading, and the flag leaf is broad and droopy. A well-managed crop can yield 4-5 tons per hectare of grain.

Crop husbandry

After collecting BARI Gom-33 seeds, they were soaked in a priming agent solution at a ratio of 1:5 (seed weight to solution volume) for 6 hours. The seeds were then thoroughly washed to remove chemical particles, and after maintaining the proper moisture content, they were stored in a refrigerator for sowing. Following the implementation of appropriate management practices, the land was prepared for use. Subsequently, fertilizers were applied at the following rates: 240, 150, 110, 120, and 8 kg ha-1 of urea, Triple Super Phosphate (TSP), Muriate of Potash (MoP), Gypsum, and Boric acid, respectively. The treated seeds were planted in the plot at a rate of 120 kg seeds ha^-1 in rows 20 cm apart by the predetermined sowing dates. Following the proper intercultural practices, such as irrigation and weeding, the crop eventually reached maturity. When the crop reached full maturity, it was first harvested individually, plot-wise, on March 16, 23, and 31, 2023, for the first, second, and third sowing dates, respectively.

Data collection procedure

Before harvesting, ten randomly chosen hills from each plot were removed. Plot-wise data on grain and straw yields were obtained on 14% moisture basis, and the results were expressed in tons per hectare (t ha^-1). Plant height, spikes m^-2, spikelets spikes^-1, and grains spikelet^-1 were measured by selecting 10 plants randomly from each plot and then averaging. The weight of 1000 grains was collected after the entire plot was harvested. Then, grain yield and straw yield were calculated after proper sun drying, and the biological yield was the sum of grain and straw yield. Finally, the harvest index was calculated as follows: (Grain yield/Straw yield) × 100.

Statistical analysis

For statistical analysis, the recorded data were collated and tabulated. The software program MSTAT was used to perform an analysis of variance at the 5% probability level. Duncan's Multiple Range Test (DMRT) was used to determine the mean differences between the treatments

Effect of sowing date on wheat

Sowing dates had a significant impact on all plant characters, including yield-contributing characters and wheat yield. Planting later than the optimum time resulted in shorter wheat plants because it created unfavorable conditions for wheat plants. When sowing was completed on November 30, the highest plant height (87.51 cm) was discovered. In comparison to the ideal sowing date of November 30, the plant (73.96 cm) was 13.55 cm shorter at the extremely late sowing date of December 30. The number of spikes m^-2 exhibited a similar pattern, with the highest value (186.79) being attained on November 30, the day of optimal sowing. Unfortunately, only 66.87 spikes m^-2 were obtained from the very late sowing date of 30 December; that amount is less than half of the optimum sowing date obtained. In terms of spikelets spike^-1, 30 December sowing yielded the lowest results, 6.20 (Table 2). When seeds were sown on November 30 (14.21) and December 15 (9.28), there was a definite benefit to the sowing date in terms of increasing spikelets spike^-1, but not after that. When it came to wheat grains spikelet^-1, the sowing on November 30 displayed the highest number of grains spikelet^-1 (2.84), while the sowing on December 30 displayed the lowest number of grains spikelet^-1 (1.72) (Table 2). Moreover, it is evident that until 15 December sowing time, the number of grains spikelet^-1 (2.20) of wheat was tolerable (Table 2). The weight of 1000-grain drastically falls according to the delay of sowing time. When the sowing date was 30 November, it produced the highest weight of 1000-grain, accounting for 40.50 g. However, when the sowing date became 30 December, the weight of 1000-grain (25.97 g) dropped by almost 15 g compared to the optimum sowing date (30 November) (Table 2). The retarded sowing also resulted in a lower wheat grain yield. The sowing date, which took place on 30 November, resulted in the highest grain yield (3.06 t ha^-1). Due to the extremely late sowing (30 December) and late sowing (15 December), wheat grain yield (1.19 t ha^-1, 1.84 t ha^-1) was reduced by 64.37% and 39.87% respectively. Furthermore, the highest straw yield (3.78 t ha^-1) was obtained from early sowing, while the lowest straw yield (1.77 t ha^-1) was found from very late sowing. When the wheat was sown on November 30, it had the most excellent harvest index (44.42%). The harvest index steadily decreased as sowing was postponed (Table 2). High temperatures caused late-sown wheat cv BARI Gom-33 to produce fewer spikes per m^-2, which could potentially negatively impact grain yield plant^-1 and 1000-grain weight. According to research by Nawaz et al. (2013) and Farooq et al. (2011), high temperatures reduced the number of grains spike^-1 and ear heads as well as hindered pollination and seed set. Better spikes m^-2 and grain yield plant^-1 evidence improved wheat performance following seed priming treatments. In the case of late-sown conditions, this lessened the harsh consequences of rising temperatures. Priming functions as a form of immunization against impending illnesses, such as high temperatures (Arun et al., 2021; Patanè et al., 2009; Wahid et al., 2008). Zulfiqar et al. (2022) reported that seed priming correlates with seedlings' capacity to tolerate both biotic and abiotic stress. The hypothesis was that pre-sowing seed treatment could improve germination, increase the germination rate, and enhance seedling vigor and growth in Bangladesh, where late wheat planting is becoming increasingly common. In overcoming different abiotic and biotic obstacles, this may help wheat seedlings.

Table 2: Effect of sowing date on plant characters, yield parameters, and yield of wheat cv BARI Gom-33

In a column, figures with the same letter do not differ significantly (as per DMRT), **=significant at 1% level of probability, NS=Non-significant.

Effect of priming agents on wheat

All yield parameters, except 1000 grain weight and straw yield, were significantly influenced by seed priming (a technique for hydrating seeds before sowing that promotes germination and consistent seedling emergence).  It was demonstrated that priming the seeds elevated the height of the wheat plant when compared to non-primed seeds. While seed priming outperformed the control (76.46 cm) by a significant margin, hydropriming (79.44 cm), CaCl₂ priming (82.53 cm), KCl priming (80.94 cm), KNO3 priming (79.81 cm), and mannitol priming (80.21 cm) did not differ significantly from one another. From Table 3, it is evident that seed priming resulted in an average increase of 5 cm in plant height. Ali et al. (2013) also found that various seed priming techniques in wheat increased plant height. Farooq et al. (2011) reported that primed seeds generally outperform control seeds in terms of dry matter production, plant height, and root weight. For the impact of seed priming, it was observed that more spikes per square meter were obtained from primed seeds than from seeds without priming. The highest number of spikes m^-2 (126.57) was produced with CaCl₂ priming, which was similar(statistically) to KCl (125.92), while other seed priming (hydro, KNO_3, mannitol) produced statistically identical results (Table 3). The lowest number of spikes m^-2 (119.56) was recorded with no priming. In terms of number of spikelets spike^-1, seed priming with CaCl₂ (11.34) performed significantly better than the control (8.73), however, there was no statistically significant difference between CaCl₂ (11.34) and KCl (10.84) priming, while KNO₃ (9.47) and hydro (8.90) priming produced statistically different results from CaCl₂ and KCl priming (Table 3). Seed priming increased yield and exceeded the control by a significant margin. According to Asadujjaman et al. (2023), primed seed treated with KCl and CaCl₂ under high temperature stress resulted in the highest plant height, number of spikes m^-2, spikelets spike^-1, grain yield, and straw yield of wheat compared to the control. When seeds primed with CaCl₂ had the highest harvest index (43.65%), and no priming produced the lowest harvest index of 38.15% (Table 3). Seed priming induced an average 5% rise in the harvest index (Table 3). To verify the foundation and maximize plant yield, Arun et al. (2021) stated that priming intended to ensure the germination process while protecting the seed from environmental stress during the seedling stage.

Table 3. Effect of seed priming on plant characters, yield parameters, and yield of wheat cv BARI Gom-33

In a column, figures with the same letter do not differ significantly (as per DMRT), **=significant at 1% level of probability, NS=Non-significant.

Interaction effect of sowing date and seed priming

All plant characters, yield parameters, and wheat yield were significantly varied when sowing date and seed priming interacted with each other. The plants with the tallest height (90.10 cm) and the highest number of spikes per m² (189.8) were observed in the CaCl₂ priming and sowing on November 30. On the contrary, the lowest height of plants (71.33 cm) was found in no priming and sowing on extremely late sowing (30 December).

To achieve the highest plant height and number of spikes m^-2, wheat should be planted on 30 November with CaCl₂ priming. Upon combining CaCl₂ priming with 30 November sowing, the most significant number of spikelets spike^-1 (15.73), grains spikelet^-1 (3.16), the highest 1000-grain weight (40.76 g), and the highest grain yield (3.37 g) were observed (Table 4, Figure 1). On the contrary, the lowest number of grains spikelet^-1 (1.23) and the weight of 1000 grains (25.86 g) were found in the combination of no priming and 30 December. The highest straw yield (4.09 t ha^-1) was produced by the interaction of mannitol priming and 30 November sowing, while the maximum harvest index (47.22%) was observed in the combination of CaCl₂ and 30 November sowing. Before December 15^th sowing, priming was advantageous in raising the harvest index, but not after that.

This study demonstrates that late-sown wheat can perform better when seed priming techniques are employed. The occurrence of low temperatures during the sowing of wheat cv. BARI Gom-33 leads to poor seed germination, establishment, and vigor of seedlings when sowing is too late. Due to inadequate stand establishment, a lack of spikes per square meter subsequently results in lower grain production, straw yield, and harvest index. Seed priming improved tiller counts, emergence, stand establishment, grain and straw yields, and harvest index in late-sown wheat (Farooq et al., 2008). Numerous seed priming techniques improved the yields of viable tillers, plant height, 1000-grain weight, yield, and grain and biological components in wheat (Ali et al., 2013). In a similar vein, Toklu et al. (2015) demonstrated that hydro-priming, PEG, and KCl treatments increased wheat grain yield relative to the control. Additionally, seed priming in wheat produced a noticeably higher grain yield (17%) compared to the non-primed control, according to Ramamurthy et al. (2015).

The highest plant height, spike m^-2, 1000-grain weight, grain yield, and straw yield of wheat cv. BARI Gom-33 under high-temperature stress was obtained in this study using primed seed, particularly CaCl₂. Other priming agents, in addition to CaCl₂, also outperformed the control. Similarly, Suryakant et al. (2000) found that the highest yields of wheat grain, straw, and biological material were obtained from sprouted seeds, followed by priming treatments with KCl, water, and ZnSO₄, and the lowest yields from dry seed sowing (control).

The current study demonstrates that seed priming, when applied later in the growing season, can effectively boost wheat plant growth and yield even in the face of heat stress. Without a doubt, seed priming with CaCl₂ proved to be the most effective method of priming. However, wheat cv BARI Gom-33's growth and yield were also enhanced by additional priming agents. These results will open up new possibilities for improving seed priming to protect late-sown wheat from heat stress, especially during the reproductive stage.

Table 4. Interaction effect of seed priming and sowing date on plant characters, yield parameters, and yield of wheat cv BARI Gom-33

In a column, figures with same letter do not differ significantly (as per DMRT), **=significant at 1 % level of probability. D₁= 30 November, D₂= 15 December, D₃= 30 December. P₁= No Priming, P₂= Hydro Priming, P₃= Priming with 20000 ppm CaCl₂, P₄= Priming with 20000 ppm KCl, P₅= Priming with 15000 ppm KNO₃, P₆= Priming with 40000 ppm mannitol.

Figure 1. Grain yield of wheat cv BARI Gom-33 as influenced by the interaction between seed priming and sowing date. The bar represents the standard error of the means. Here, D1=30 November, D2= 15 December, D3= 30 December P1= No Priming, P2= Hydro Priming, P3= Priming with 20000 ppm Cacl₂, P4= Priming with 20000 ppm KCl, P5= Priming with 15000 ppm KNO₃, P6= Priming with 40000 ppm mannitol

The study found that the sowing date, priming agent, and their interaction significantly impacted the plant height, spikes per m², spikelets per panicle, grains per spike, and grain yield of wheat. Seed priming showed a positive effect on plant characteristics, yield parameters, and yield of wheat cv BARI Gom-33. The grain yield of BARI Gom-33 decreased with a delay in sowing, with the highest yield (3.06 t ha^-1) found when sowing on 30 November. Seed priming with CaCl₂ resulted in the highest grain yield (2.26 t ha^-1), while no priming produced the lowest yield of 1.60 t ha^-1. On average, seed priming increased grain yield by 0.66 t ha^-1 compared to the control. A delay in sowing caused poor crop stand and growth; however, seed priming improved stand establishment and growth, resulting in a substantial increase in grain yield. Therefore, it is recommended to sow wheat by November 30, after seed priming, ideally with 20,000 ppm CaCl₂. If sowing is delayed, seed priming is essential to alleviate temperature stress partially. However, this research is conducted in a single year and location; hence, multi-location and especially multi-year trials should be conducted based on these preliminary results before drawing a conclusion.

Acharjee, T. K. and Shariot-Ullah, M. 2021. Irrigation requirement and possibility of high-temperature stress of wheat for different planting dates under climate change in Bogura, Bangladesh. J. Bangladesh Agril. Univ., 19: 277–286. https://doi.org/10.5455/JBAU.41181

Afzal, I., Basra, S. M. A., Ahmad, N., Cheema, M. A., Warriach, E. A. and Khaliq, A. 2002. Effect of priming and growth regulator treatment on emergence and seedling growth of hybrid maize (Zea mays L.). Int. J. Agric. Biol., 4: 302–306.

Ahmed, S., Alam, M. J., Awan, T. H. and Islam, A. K. M. M. 2019. Herbicidal weed control in drill sown spring wheat under Bangladesh condition. Fundam. Appl. Agric., 4: 839–848. https://doi.org/10.5455/faa.34774

Ali, H., Iqbal, N., Shahzad, A. N., Sarwar, N., Ahmad, S. and Mehmood, A. 2013. Seed priming improves irrigation water use efficiency, yield and yield components of late-sown wheat under limited water conditions. Turk. J. Agric. For., 37: 534–544. https://doi.org/10.3906/tar-1207-70

Arun, M. N., Hebbar, S. S., Bhanuprakash, B., Senthivel, T. A. K., Nair, A. K., Padmavathi, G., Pandey, P. and Singh, A. 2021. Seed Priming: The Way Forward to Mitigate Abiotic Stress in Crops. In: M. Hasanuzzaman and K. Nahar (Eds.), Plant Stress Physiology - Perspectives in Agriculture. Intech Open.

Asadujjaman, M., Anwar, M. P., Hossain, A., Kheya, S. A., Hasan, A. K., Yeasmin, S. and Islam, A. K. M. M. 2023. Augmenting spring wheat productivity through seed priming under late-sown condition in Bangladesh. Res. Agric. Sci., 54: 57–67. https://doi.org/10.5152/AUAF.2023.23112

BBS (Bangladesh Bureau of Statistics). 2022. Statistical Yearbook of Bangladesh. Statistics Division, Ministry of Planning, Government of the People’s Republic of Bangladesh, Dhaka. pp. 39–42.

Farhad, M., Kumar, U., Tomar, V., Bhati, P. K., Krishnan, J. N., Barek, V., Brestic, M. and Hossain, A. 2023. Heat stress in wheat: a global challenge to feed billions in the current era of the changing climate. Front. Sustain. Food Syst., 7: 1203721. https://doi.org/10.3389/fsufs.2023.1203721

Farooq, M., Basra, S. M. A., Khalid, M., Tabassum, R. and Mahmood, T. 2006. Nutrient homeostasis, reserves metabolism and seedling vigor as affected by seed priming in coarse rice. Can. J. Bot., 84: 1196–1202. https://doi.org/10.1139/b06-088

Farooq, M., Basra, S. M. A., Rehman, H. and Saleem, B. A. 2008. Seed priming enhances the performance of late sown wheat (Triticum aestivum L.) by improving the chilling tolerance. J. Agron. Crop Sci., 194: 55–60. https://doi.org/10.1111/j.1439-037X.2007.00287.x

Farooq, M., Bramley, H., Palta, J. A. and Siddique, K. H. 2011. Heat stress in wheat during reproductive and grain filling phases. Crit. Rev. Plant Sci., 30: 491–507. https://doi.org/10.1080/07352689.2011.615687

Islam, A. K. M. M., Uddin, M. N., Yeasmin, S., Kheya, S. A., Islam, M. S., Ahmed, S., Hossain, A. and Anwar, M. P. 2023. Preliminary report on the comparative weed suppressibility of Bangladeshi wheat varieties. Heliyon, 9: e14942. https://doi.org/10.1016/j.heliyon.2023.e14942

Kumar, H., Chugh, V., Kumar, M., Gupta, V., Prasad, S., Kumar, S., Singh, C. M., Kumar, R., Singh, B. K., Panwar, G. and Kumar, M. 2023. Investigating the impact of terminal heat stress on contrasting wheat cultivars: a comprehensive analysis of phenological, physiological, and biochemical traits. Front. Plant Sci., 14: 1189005. https://doi.org/10.3389/fpls.2023.1189005

Maasoumeh, A. A. and Mohammad, S. 2014. The effect of osmo and hormone priming on germination and seed reserve utilization of millet seeds under drought stress. J. Stress Physiol. Biochem., 10: 214–221.

Modarresi, M., Mohammadi, V., Zali, A. and Mardi, M. 2010. Response of wheat yield and yield related traits to high temperature. Cereal Res. Commun., 38: 23–31. https://doi.org/10.1556/CRC.38.2010.1.3

Nascimento, W. M., Huber, D. J. and Cantliffe, D. J. 2013. Carrot seed germination and respiration at high temperature in response to seed maturity and priming. Seed Sci. Technol., 41: 164–169. https://doi.org/10.15258/sst.2013.41.1.19

Nawaz, A., Farooq, M., Cheema, S. A. and Wahid, A. 2013. Differential response of wheat cultivars to terminal heat stress. Int. J. Agric. Biol., 15: 1354–1358.

Ortiz, R., Sayre, K. D., Govaerts, B., Gupta, R., Subbarao, G., Ban, T., Hodson, D., Dixon, J. M. and Ivan, O. M. 2008. Climate change: can wheat beat the heat? Agric. Ecosyst. Environ., 126: 46–58. https://doi.org/10.1016/j.agee.2008.01.019

Paparella, S., Araujo, S. S., Rossi, G., Wijayasinghe, M., Carbonera, D. and Balestrazzi, A. 2015. Seed priming: state of the art and new perspectives. J. Plant Cell Rep., 34: 1281–1293. https://doi.org/10.1007/s00299-015-1784-y

Patanè, C., Cavallaro, V. and Cosentino, S. L. 2009. Germination and radicle growth in unprimed and primed seed of sweet sorghum as affected by reduced water potential in NaCl at different temperatures. Ind. Crops Prod., 30: 1–8. https://doi.org/10.1016/j.indcrop.2008.12.005

Qasim, M., Qamer, M., Faridullah, F. and Alam, M. 2008. Sowing dates effect on yield and yield components of different wheat varieties. J. Agric. Res. (Lahore)., 46: 135–140.

Rafi, H., Dawar, S. and Zaki, M. J. 2015. Seed priming with extracts of Acacia nilotica (L.) Willd. ex Delile and Sapindus mukorossi (L.) plant parts in the control of root rot fungi and growth of plants. Pak. J. Bot., 47: 1129–1135.

Ramamurthy, V., Venugopalan, M. V., Parhad, V. N. and Prasad, J. 2015. Effect of seed priming on emergence and yield of late sown wheat (Triticum aestivum L.) on Typic Haplusterts of Central India. Indian J. Agric. Res., 49: 245–249. https://doi.org/10.5958/0976-058X.2015.00038.4

Rehman, H. U., Basra, S., Ahmed, M. and Farooq, M. 2011. Field appraisal of seed priming to improve the growth, yield, and quality of direct seeded rice. Turk. J. Agric. For., 35: 357–365. https://doi.org/10.3906/tar-1004-954

Reynolds, M. P., Hays, D. and Chapman, S. 2010. Breeding for adaptation to heat and drought stress. In: Climate Change and Crop Production, Reynolds, M. P. (ed.). CABI, Oxfordshire. pp. 71–91.

Reynolds, M. P., Nagarajan, S., Razzaque, M. A. and Ageeb, O. A. A. 2001. Breeding for adaptation to environmental factors: Heat tolerance. In: Application of Physiology in Wheat Breeding, Reynolds, M. P., Ortiz-Monasterio, J. I. and McNab, A. (eds.). CIMMYT, Mexico, DF. pp. 124–135.

Rosegrant, M. W. and Agcaoili, M. 2010. Global food demand, supply and price prospects to 2010. Int. Food Policy Res. Inst., Washington, D.C., USA. pp. 11–20.

Singh, J., Chhabra, B., Raza, A., Yang, S. H. and Sandhu, K. S. 2023. Important wheat diseases in the US and their management in the 21st century. Front. Plant Sci., 13: 1010191. https://doi.org/10.3389/fpls.2022.1010191

Soleimanzadeh, H. 2013. Effect of seed priming on germination and yield of corn. Int. J. Agric. Crop Sci., 5: 366–369.

Srivastava, A. B., Singh, K. K., Supriya, S. K., Mishra, H. and Ahmad, R. 2023. Production and export dynamics of wheat in India. Int. J. Stat. Appl. Math., 8: 206–209. https://doi.org/10.22271/maths.2023.v8.i3Sc.1023

Suryakant, Pahuja, S. S. and Verma, S. S. 2000. Productivity of late sown wheat (Triticum aestivum) as influenced by different seed priming treatments. Haryana J. Agron., 16: 35–39.

Tahir, M., Ali, A., Nadeem, M. A., Hussain, A. and Khalid, F. 2009. Effect of different sowing dates on growth and yield of wheat (Triticum aestivum L.) varieties in district Jhang, Pakistan. Pak. J. Life Soc. Sci., 7: 66–69.

Toklu, F., Baloch, F. S., Karaköy, T. and Özkan, H. 2015. Effects of different priming applications on seed germination and some agro morphological characteristics of bread wheat (Triticum aestivum L.). Turk. J. Agric., 39: 1005–1013. https://doi.org/10.3906/tar-1404-41

Trnka, M., Dubrovský, M., Semeradova, D. and Žalud, Z. 2004. Projections of uncertainties in climate change scenarios into expected winter wheat yields. Theor. Appl. Climatol., 77: 229–249. https://doi.org/10.1007/s00704-004-0035-x

Wahid, A., Noreen, A., Basra, S. M. A., Gelani, S. and Farooq, M. 2008. Priming induced metabolic changes in sunflower achenes improve germination and seedling growth. Bot. Stud., 49: 343–350.

Zulfiqar, F., Nafees, M., Chen, J., Darras, A., Ferrante, A., Hancock, J. T., Ashraf, M., Zaid, A., Latif, N., Corpas, F. J. and Altaf, M. A. 2022. Chemical priming enhances plant tolerance to salt stress. Front. Plant Sci., 13: 946922. https://doi.org/10.3389/fpls.2022.946922