Introduction

Wheat (Triticum aestivumL.) is one of the most significant cereal crops globally, not only for its nutritional value but also for its economic importance. As a staple food in many countries, including Pakistan, wheat plays a pivotal role in ensuring food security. In Pakistan, 12.55% of households’ monthly income is spent on wheat flour, with the per capita wheat consumption reaching 118 kg per year, compared to an annual production of 131 kg per capita1. The productivity and yield of wheat directly affect its availability, which has implications for national and household food security. Variations in wheat supply impact consumers, farmers, and all those dependent on agriculture, either directly or indirectly2.

In recent years, Pakistan has faced challenges in maintaining wheat productivity. In the 2021-22 growing season, wheat was sown on 8,976 thousand hectares, yet production decreased by 3.9%, amounting to 27.464 million tons, a 2.1% yield decline compared to the previous year3,4. Multiple factors contribute to this low productivity, but a significant reason is farmers’ reluctance to adopt recommended production technologies, such as optimal seed rates, fertilizer applications, and appropriate planting techniques.

One critical factor influencing wheat yield is the seed rate. An optimal seed rate is essential for achieving adequate plant density, while a suboptimal rate can either reduce plant density or increase competition among plants, both of which negatively impact yield5. Studies like that of Seleiman et al. showed that increasing seed rates (250, 300, 350, and 400 gm−2) led to increased wheat yield, although it also caused a reduction in grain weight6. Similarly, Iqbal et al. demonstrated that using a seed rate of 150 kg ha⁻¹ optimized various yield-contributing factors, resulting in a yield of 4.2 t ha⁻¹7.

In addition to seed rate, planting methods significantly influence wheat productivity. Research by Chaudhary et al. showed that bed planting produced 13% more yield than traditional broadcast and drill sowing methods8. Given the critical role of seed in crop production, proper stand establishment, which depends on optimal seed germination and seedling vigor, is essential. Environmental and abiotic stressors often negatively affect germination, leading to subpar crop yields. Priming is a simple and effective method to overcome these restrictions by promoting seed germination through regulated hydration and drying processes that improve germination efficiency9. Seed priming can reduce fertilizer use, synchronize seed germination, and enhance crop production in an environmentally sustainable manner10.

Triticum aestivum, the common wheat, has been the subject of extensive research and debate for decades. Hexaploid wheat, the most common form, originated from the crossing of tetraploid wheat (T. turgidum) and diploid Aegilops tauchii var. strangulata11. Archaeological research suggests that wheat originated in the Fertile Crescent around 8,000 to 10,000 years ago12,13. While T. aegilopoides is widely cultivated in the Middle East, T. monococcum, or Einkorn wheat, is grown on a smaller scale14.

In Pakistan, wheat remains a vital crop, but yields have been significantly affected by farmers’ reluctance to adopt modern agricultural technologies. One key challenge is achieving an optimal crop stand, which is influenced by seed rate and planting methods. The current study aims to improve the germinability of two wheat varieties through priming techniques and to determine the optimal seed rate and planting method for clayey soils under the arid climate of Dera Ismail Khan. This research is crucial for identifying strategies to enhance wheat yield and ensure food security in regions with challenging growing conditions.

Materials and methods

Site description

The research was conducted at the Agronomy research area of Gomal University, D.I. Khan, during the Rabi seasons of 2017, 2018, and 2019. The experimental site is characterized by a semi-arid climate with hot summers and mild winters. Meteorological data recorded during the study showed average temperatures ranging from 12 °C to 24 °C during the Rabi season, with an annual rainfall of approximately 250–300 mm, primarily concentrated during the monsoon period. Initial soil properties at the experimental site indicated a sandy loam texture with a slightly alkaline pH (7.5–8.0), moderate organic matter content, and average nutrient availability. The experiments tested two wheat varieties: Israr Shaheed (a short-duration variety) and Gomal (a long-duration variety). The seeds of Israr Shaheed and Gomal wheat varieties were sourced from the Cereal Crops Research Institute (CCRI), Pirsabak, Nowshera, Pakistan. These varieties were selected to evaluate their response to different seed rates, sowing methods, and priming techniques under the agroecological conditions of the research area.

Treatments and design

In 1st experiment, the influence of different priming techniques on wheat crop growth and yield was studied. Following priming treatments were studied in the experiments including T1: Control, T2: Tap water (primed for 2 h), T3: Sewage water (primed for 3 h), T4: Farmyard manure (primed for 6 h), T5: Compost manure (primed for 8 h), T6: Poultry manure (primed for 8 h), T7: Press mud (primed for 12 h) and T8: Sodium chloride.

In 2nd experiment, sowing techniques and wheat performance under the agroecology of Dera Ismail Khan, KPK, Pakistan were studied. The following treatments were studied in the experiments including, T1: Normal sowing technique (Normal sowing technique involved sowing seeds in prepared dry soil using a seed drill, ensuring they are planted at a consistent depth and spacing), T2: Dry seed in a flooded field (the field was flooded, and the dry seeds were then scattered over the water-covered soil through broadcast method), T3: Dry seed drill method (Drill Method), T4: Sprouted seeding in a flooded field (Broadcast Method), T5: Soaked seeding in a flooded field (Drill Method) and T6: Soaked seed followed by flooding (Drill Method).

In 3rd experiment, different seeding densities’ effect on wheat crop growth and yield was studied. Following treatments were studied in the experiments including, T1: 100 kg ha-1, T2: 125 kg ha-1, T3: 150 kg ha-1, T4: 175 kg ha-1, T5: 200 kg ha-1, T6: 225 kg ha-1 and T7: 250 kg ha-1. A randomized complete block design was used for the research. All experiments were conducted in three replications with a plot area of 6 m2, maintaining 30 cm and 10 cm distances between plants and rows, respectively.

Intercultural operation/ agronomic management technique

Throughout the experiments, standard agronomic practices were followed to ensure optimal growth conditions for both wheat varieties, Israr Shaheed and Gomal. The fields were prepared using thorough plowing, followed by harrowing to achieve a fine tilth. The seedbed was leveled before sowing to ensure uniform seed distribution and proper water management. Fertilizer application was based on soil test results, with a recommended dose of nitrogen (N), phosphorus (P), and potassium (K) applied at rates of 120:90:60 kg ha⁻¹, respectively. Nitrogen was applied in split doses, with half at sowing and the remaining half at the tillering stage. Phosphorus and potassium were applied as basal doses at sowing. Irrigation was provided at critical growth stages, including tillering, booting, and grain filling, with additional waterings depending on rainfall patterns during the season. Water was managed carefully to prevent both waterlogging and drought stress. Weed control was carried out through manual weeding at regular intervals, particularly during the early growth stages, to reduce competition for nutrients, water, and light. A pre-emergence herbicide (Pendimethalin) was applied at a rate of 1.25 kg ha⁻¹ to manage early germinating weeds, followed by post-emergence herbicide applications as needed. Pest and disease management included regular field monitoring for common wheat pests (e.g., aphids and armyworms) and diseases (e.g., rust and blight). Insecticides and fungicides were applied as necessary to minimize crop loss, following integrated pest management (IPM) principles to reduce pesticide use and promote sustainable agriculture. During the growth period, plots were also inspected for soil moisture conditions and nutrient deficiency symptoms, with corrective actions taken as required (e.g., supplemental foliar feeding in cases of nutrient stress).

Yield parameters

A measuring tape was used to measure the plant heights of both varieties viz. Israr Shaheed and Gomal. For this purpose, we measured a sample of ten plants from the base to the tip. We obtained average results for each treatment by adding the heights of ten plants and dividing them by 10. In each plot, a square meter area was chosen randomly and in each treatment’s number of stems and tillers (m-2) was counted. We measured spike length in centimeters from a sample (10 plants) and then averaged the results for each treatment. To determine the mean results for each treatment, we counted number of spikelets (spike-1) in each spike in ten plants. Randomly, ten plants were chosen as a sample and their number of grains (spike-1) was counted in each spike and averaged. We counted the weight of 1000 grains (gm) in each treatment, and then they were weighed on an electronic balance. The yield of grain (kg ha-1) was obtained from each plot and the obtained results were converted into (kg ha-1) through the given formula:

$$\:Grain\:yield\:\left({kg\:ha}^{-1}\right)=\frac{Grain\:yield\:\left({g\:plot}^{-1}\right)}{6}\times\:10$$

From each plot, the biological yield (kg ha-1) was obtained, and the results were collected into kg ha-1 through the given formula:

$$\:Biological\:yield\:\left({kg\:ha}^{-1}\right)=\frac{Biological\:yield\:\left({g\:plot}^{-1}\right)}{6}\times\:10$$

The given formula was used for obtaining the harvest index (%age):

$$\:Harvest\:index\:\left(\%\right)=\frac{Economic\:yield}{Biological\:yield}\times\:100$$

Statistical analysis

The variance technique was analyzed statistically for the data obtained in all the experiments. For the comparison of means at a 5% probability level, the Least Significant Difference (LSD) test was applied using Statistix 10 (Analytical Software, Tallahassee, FL, USA; www.statistix.com).

Results

Effect of different priming techniques on the growth and yield of wheat crop

The results of the study on the effect of different priming techniques on the growth and yield of wheat crops are summarized in Table 1. For the variety Israr Shaheed, the highest plant height was recorded in the treatment with farmyard manure priming (T4), measuring 111.3 ± 6.5 cm, which was significantly greater than the other treatments. In contrast, the lowest plant height of 89.8 ± 4.9 cm was observed in T5. The Gomal variety exhibited a similar trend, with the tallest plants also found in T4 (125.3 ± 5.2 cm) and the shortest in T3 (102.7 ± 2.3 cm), emphasizing the positive impact of farmyard manure on plant growth.

In terms of the number of tillers, Israr Shaheed produced the most tillers per square meter in T4 (335.7 ± 20.7), significantly outperforming other treatments, with T7 recording the lowest count of 277.0 ± 9.4. The Gomal variety showed a comparable pattern, where the highest tiller count was also observed in T4 (345.0 ± 22.2), while T3 produced the least (288.7 ± 1.4). These findings suggest that farmyard manure priming effectively enhances tiller development in both wheat varieties.

Spike length, another important growth parameter, was the longest in Israr Shaheed with T4 (8.6 ± 0.4 cm), while the control treatment (T1) yielded the shortest spikes at 5.6 ± 1.0 cm. Gomal demonstrated a similar trend, with the maximum spike length also in T4 (7.6 ± 0.3 cm) and the minimum in T3 (5.2 ± 0.1 cm). Additionally, the number of spikelets per spike was significantly highest in Israr Shaheed for T4 (27.2 ± 0.7), compared to the control T1 (18.5 ± 0.7). In Gomal, T4 again resulted in the most spikelets (31.0 ± 0.1), while T3 showed the lowest count (19.3 ± 0.9).

Regarding grain development, Israr Shaheed had the highest number of grains per spike in T4 (45.5 ± 0.02), significantly higher than the control T1 (24.3 ± 0.9). Similarly, Gomal exhibited a maximum of 48.7 ± 0.5 grains per spike in T4, with the minimum found in T1 (28.2 ± 2.6). The thousand-grain weight for Israr Shaheed was heaviest in T5 (49.2 ± 0.1 g), while the lowest weight of 29.2 ± 0.2 g was recorded in T1. Gomal’s highest grain weight was also in T5 (42.3 ± 0.2 g), contrasting with the minimum of 32.2 ± 1.3 g in T1.

In terms of yield, the grain yield for Israr Shaheed was highest in T4 (4.4 ± 0.1 t ha⁻¹) and lowest in T3 (2.0 ± 0.1 t ha⁻¹). Gomal similarly showed a maximum yield of 4.6 ± 0.1 t ha⁻¹ in T4 and a minimum of 2.9 ± 0.1 t ha⁻¹ in T1. Biological yield followed a similar pattern, with Israr Shaheed achieving the highest yield in T4 (11.8 ± 0.4 t ha⁻¹) and the lowest in T1 (8.8 ± 0.3 t ha⁻¹). Gomal’s biological yield also peaked in T4 (11.3 ± 0.5 t ha⁻¹) and was lowest in T1 (9.3 ± 0.1 t ha⁻¹).

Finally, the harvest index was significantly highest in Israr Shaheed for T4 (38.7 ± 2.3%), while T3 showed the lowest index at 27.7 ± 0.2%. Gomal exhibited a similar trend, with the highest harvest index in T4 (41.5 ± 2.6%) and the lowest in T3 (27.9 ± 1.5%). Overall, farmyard manure priming (T4) consistently resulted in the best growth and yield parameters for both wheat varieties, demonstrating its efficacy compared to other treatments.

Effect of sowing techniques on the performance of short and long-duration wheat varieties under the agro-ecology of D.I. Khan, KPK, Pakistan

The results presented in Table 2 illustrate the effects of various sowing techniques on the performance of short and long-duration wheat varieties, Israr Shaheed and Gomal, under the agroecological conditions of D. I. Khan, KPK, Pakistan.

Table 1 Effect of different priming techniques on the growth and yield of wheat crop.
Full size table

In terms of plant height, significant variations were observed across the different treatments. The tallest plants of Israr Shaheed were recorded with the dry seed drill method (T3), measuring 105.5 cm, closely followed by the dry seed in the flooded field (T2) at 100.5 cm. Similarly, Gomal achieved a maximum height of 101.7 cm with the dry seed drill method. Conversely, the shortest plants for both varieties were measured with the soaked seeding in flooded fields (T5), at 93.3 cm for Gomal and 93.9 cm for Israr Shaheed. These findings highlight the efficacy of modern sowing techniques in promoting plant growth.

The number of tillers per square meter also varied significantly among treatments. Israr Shaheed showed the highest tiller count of 398.2 in response to the dry seed drill method (T3), while Gomal exhibited a maximum of 406.7 under the same treatment. In contrast, the conventional sowing method (T1) resulted in the lowest tiller counts for both varieties.

When examining spike length, Israr Shaheed achieved its longest spikes (8.3 cm) using the dry seed drill method (T3), while Gomal also performed well with a spike length of 8.2 cm under the same treatment. The soaked seeding techniques led to shorter spikes for both varieties, underscoring the advantages of dry-sowing methods for spike development.

The number of spikelets per spike revealed that Israr Shaheed had the highest count (29.8) with the dry seed drill method (T3), while Gomal recorded its maximum spikelets (35.5) under the same treatment. Soaked seeding methods resulted in significantly fewer spikelets.

In terms of grains per spike, Israr Shaheed produced the highest count (54.3) with the dry seed drill method (T3), while Gomal also performed best with this method, yielding 51.6 grains per spike. The soaked seed treatments, however, resulted in fewer grains, emphasizing the positive influence of improved sowing techniques on grain production. The 1000-grain weight showed that Israr Shaheed had its heaviest seeds (45.3 g) with the sprouted seeding method (T4), whereas Gomal reached its peak weight (45.0 g) under the same treatment. In contrast, the lightest seeds for both varieties were recorded with the dry seed drill method (T3). This variation in grain weight highlights how different management practices can significantly impact seed quality.

Table 2 The sowing techniques’ effect on short and long-duration wheat varieties performance under the agro-ecology of D. I. Khan, KPK, Pakistan.
Full size table

Grain yields were notably affected by sowing techniques, with Israr Shaheed achieving the highest yield (4.3 t ha⁻¹) under the dry seed drill method (T3) and Gomal reaching its maximum yield (4.6 t ha⁻¹) using the same technique. The conventional method (T1) resulted in the lowest grain yields for both varieties, indicating that modern sowing practices can enhance agricultural productivity. Finally, the biological yield showed significant differences among treatments. Israr Shaheed recorded its highest biological yield (13.6 t ha⁻¹) under the soaked seed followed by the flooding method (T5), while Gomal’s maximum biological yield (14.2 t ha⁻¹) was noted with normal sowing techniques (T1). The harvest index also varied, with Israr Shaheed achieving the highest index (33.5%) under soaked seed followed by flooding (T6), and Gomal showing its best harvest index (33.9%) with the same treatment.

Effect of various seeding densities on the growth and yield of wheat crop

The study results, as shown in Table 3, reveal that different seeding densities significantly influenced the growth and yield of both the Israr Shaheed and Gomal wheat varieties. Plant height peaked at 150 kg ha⁻¹ for both varieties, with Israr Shaheed reaching 111.0 cm and Gomal 111.7 cm. However, at the highest density (250 kg ha⁻¹), plant height decreased significantly for both varieties, indicating that higher seeding rates negatively impacted growth.

The number of tillers per square meter also followed a similar trend, with the highest tiller count observed at 150 kg ha⁻¹ (411.6 for Israr Shaheed and 408.2 for Gomal). As the seeding density increased, the number of tillers declined, especially at 250 kg ha⁻¹, where the lowest values were recorded. Spike length was maximized at 150 kg ha⁻¹ for both varieties but decreased at higher densities.

Number of spikelets and grains per spike was highest at 150 kg ha⁻¹, with Israr Shaheed and Gomal producing 34.3 spikelets and around 50 grains per spike, respectively. Higher seeding densities led to a notable decline in these parameters, particularly at 250 kg ha⁻¹. Grain yield was significantly affected by seeding density, with the maximum yield recorded at 150 kg ha⁻¹ for both varieties (4.6 t ha⁻¹ for Israr Shaheed and 4.5 t ha⁻¹ for Gomal). Higher densities resulted in reduced yields. Biological yield, although relatively stable across treatments, was slightly higher at 100–175 kg ha⁻¹ but decreased marginally at the highest densities.

Table 3 Various seeding densities effect on the growth and yield of wheat crop.
Full size table

The harvest index followed a similar pattern, with the best results at 150 kg ha⁻¹ and a marked reduction at 250 kg ha⁻¹. Overall, a seeding density of 150 kg ha⁻¹ optimized growth and yield, while higher densities led to a decline in most parameters due to increased competition for resources.

Discussion

This study’s results emphasize priming techniques’ role in modulating wheat growth and yield, particularly through their interactions with different wheat varieties. The increased height observed in the Gomal variety, especially with farmyard manure priming, can be attributed to improved nutrient availability and enhanced moisture retention provided by organic amendments. Organic manures, such as farmyard and poultry manure, enhance soil properties, creating a more favorable growing environment, which is consistent with Farooq et al., who highlighted the benefits of nutrient- and water-priming in early plant growth15,16,17,18,19,20,21,22. The observed differences in plant height between Gomal and Israr Shaheed likely stem from their genetic variation, affecting their responsiveness to priming techniques.

Tiller number, a key determinant of wheat yield, increased substantially in Gomal, particularly with farmyard and poultry manure treatments. This suggests that organic priming agents may enhance hormonal balance and nutrient absorption, which support tiller development. Similar findings have been reported with zinc oxide (ZnO) priming, promoting nutrient availability and tiller production22,23,24,25,26,27. In contrast, sewage water and pressed mud priming resulted in fewer tillers, possibly due to reduced nutrient efficiency and poorer soil conditions.

Spike length, another yield determinant, responded positively to farmyard manure priming, particularly in Israr Shaheed. This aligns with prior studies indicating that organic manure provides a steady supply of nutrients, which supports spike elongation27,28,29,30,31,32,33,34,35,36. Interestingly, Gomal exhibited longer spikes when primed with sewage water, suggesting this variety might possess adaptive mechanisms that allow it to tolerate unconventional priming agents.

The number of spikelets and grains per spike was consistently higher in Gomal across treatments, indicating greater reproductive efficiency in this variety. Both farmyard and poultry manure were particularly effective in increasing these traits, likely due to enhanced nutrient uptake and flower initiation37. Gomal’s superior performance in these areas suggests a genetic predisposition for higher yield potential, supported by studies demonstrating the positive effects of organic priming on reproductive structures in wheat38,39,40.

The 1000-grain weight varied among treatments, with compost manure producing heavier grains in Israr Shaheed41. This suggests that compost-based priming improves soil structure and nutrient availability, aiding in grain filling. However, farmyard and poultry manure priming resulted in lighter grains, indicating a potential trade-off between spikelet number and grain size, a phenomenon also noted in other research42,43,44.

Grain yield was significantly higher in Gomal, especially when primed with farmyard manure, which likely promoted better nutrient utilization and stress resilience. Similar studies have shown that organic priming agents improve the harvest index by optimizing the allocation of resources between vegetative and reproductive growth45. Moreover, the higher biological yield observed in both varieties, particularly with sodium chloride and poultry manure priming, highlights the potential of these treatments to enhance crop productivity under various stress conditions46.

Sowing methods also played a significant role in plant growth and yield. The dry seeding followed by the flooding method led to taller plants, particularly in Israr Shaheed, likely due to better root establishment and nutrient uptake47. This finding is consistent with the work of Amin and Khan, who demonstrated the advantages of precise sowing techniques in enhancing wheat growth48. Enhanced tiller production under this method further supports the importance of optimized sowing techniques in boosting yield, as both varieties performed better when subjected to this approach. As observed in previous studies, Modern sowing methods promote optimal seed placement and early seedling establishment, leading to better yield outcomes49.

Spike length and spikelet number were also influenced by sowing methods, with the longest spikes recorded for Israr Shaheed under dry seeding followed by flooding50,51,52,53. This physiological benefit of the method has been confirmed by earlier research on the effects of sowing techniques54. Increased spikelet numbers under the same treatment suggest that this method may enhance spikelet initiation, further improving yield potential. The increase in grains per spike supports findings that different sowing methods can significantly impact wheat yield components55.

The 1000-grain weight showed variability based on sowing methods, with heavier grains observed in both varieties under sprouted seeding in flooded fields56. This result underscores the advantages of this method for optimizing nutrient uptake during grain filling. Effective water management during critical growth stages is crucial for improving grain quality and yield57.

Finally, the significant increases in grain and biological yields associated with dry seeding followed by flooding further emphasize the benefits of modern sowing techniques58. The observed yields (4.6 t ha⁻¹ for Gomal and 4.3 t ha⁻¹ for Israr Shaheed) underscore the effectiveness of this method in maximizing wheat production. This aligns with findings that suggest diverse sowing methods can result in significant variations in yield59,60. Pre-germination in flooded fields, contributing to better seedling vigor and establishment, highlights the pivotal role of agronomic practices in improving wheat yield outcomes61.

Optimal seeding densities (125–150 kg ha⁻¹) provide the best conditions for wheat growth by minimizing competition for resources. The results indicate that moderate densities promote better tiller development, spike length, and grain number per spike, leading to higher yields. High seeding densities (200–250 kg ha⁻¹) increase competition and reduce yield, though the 1000-grain weight may be higher due to fewer total grains per spike62,63,64,65. These findings highlight the importance of balancing plant population and resource allocation to maximize yield potential.

Conclusions

In the first experiment, various priming techniques were studied. The results revealed that all treatments significantly influenced the growth and yield parameters of wheat varieties. Notably, the interaction of farmyard manure priming with both wheat varieties was particularly promising, leading to improved growth and yield. Thus, farmyard manure priming is recommended for achieving a better crop stand and higher yields in wheat cultivation. Under the agroecological conditions of Dera Ismail Khan, the practice of dry sowing followed by flooding demonstrated superior performance in terms of yield and yield attributes. This method is advisable for general use to enhance wheat productivity in the region. Furthermore, the study indicated that wheat yield and yield attributes were optimized at a seeding rate of 150 kg ha⁻¹. Increasing the seed rate beyond this point resulted in reduced yields, likely due to excessive plant-plant competition. Therefore, for optimal wheat yield, it is recommended to maintain a seeding rate of 150 kg ha⁻¹ to avoid competition and potential yield losses. These findings emphasize the importance of adopting precise agronomic practices tailored to local conditions to maximize wheat productivity. Future research should continue to refine these techniques and explore their applicability across different wheat varieties and agroecological zones, contributing to food security and agricultural sustainability in the region.