Global food security requires food production to be increased in the future decades. Agro-Ecological Zones (AEZ) methodology is a successful approach used in land evaluation studies to support sustainable agricultural development. This approach can facilitate finding suitable areas for wheat production on a global scale. This study was conducted based on a climate zone map, soil data, wheat cultivation area, yield, and production under irrigated and rainfed conditions, worldwide. The results for irrigated wheat indicated that there is an area of 59.5 Mha with an average yield of 4.02 t/ha which leads to the production of about 239.6 Mt of grain yield. Furthermore, climate zones (CZs) of 8002, 5203, 5302, 5403, and 8102 have the highest wheat production with an average of 20.7, 14.2, 13.3, 11.8, 11.5 Mt, respectively. The highest amount of irrigated wheat production has been achieved in soil type code 17 (Loam LF120), which has a cultivation area of around 23.6 Mha and a production of about 106.8 Mt. Rainfed wheat production is 410 Mt, and the cultivation area is 160.2 Mha. The highest rainfed wheat production with an average of 17 Mt was related to the 3702 CZ, followed by the other CZs (3802, 1303, 1203, 3602, 4602, etc.). The soil codes 11 (Loam HF120), 10 (Loam HF180), and 14 (Loam MF120) showed the highest rainfed wheat production. The findings of this study can be useful for agricultural scientists, authorities, and decision-makers around the world to find suitable lands to expand wheat cultivation and also to find new locations for increasing global wheat production to feed the increasing population in the world.

Wheat plays a crucial role in global food security, serving as a vital food crop that feeds billions of people worldwide. Currently, Russia and Ukraine are responsible for exporting approximately 25% of the world’s wheat, making any issues in these regions a cause for concern regarding global wheat supply. The problems faced in these areas have led to a surge in wheat prices worldwide. Consequently, it becomes necessary to explore alternative regions that can compensate for the decline in wheat production and supply. This study focuses on wheat production and yield in major producing countries, utilizing the GYGA (Global Yield Gap Atlas) protocol for predictions. The findings reveal a global wheat production gap of 270,378,793 tons. Notably, the largest gap in irrigated wheat production exists in countries like China, India, Pakistan, Turkey, Iran, Afghanistan, Uzbekistan, Egypt, and Azerbaijan. Additionally, the rainfed wheat production gap on a global scale amounts to 545,215,692 tons, with Russia, the USA, Kazakhstan, Australia, Ukraine, China, Turkey, Canada, India, and France having the most significant production gaps. Through boundary line analysis, specific criteria were identified for suitable areas of irrigated and rainfed wheat cultivation. For irrigated conditions, the temperature range of 3000 to 7000 GDD (Growing Degree Days) and a temperature seasonality of 3 were determined as favorable. Under rainfed conditions, the suitable areas encompass a temperature range of 2000 to 4000 GDD, an aridity index exceeding 600, and a temperature seasonality of 2. Thirteen countries possess extensive agricultural land within the climatic codes favorable for irrigated wheat cultivation. Approximately 50% of the agricultural lands within these countries, corresponding to the total arable area for irrigated wheat, fall within the climatic codes 3403, 5403, 5303, 4303, 5503, 5203, 3503, 3303, and 4103. China, the United States, Ukraine, Russia, and Iran are the top five countries with favorable lands for irrigated wheat cultivation. Similarly, fourteen countries have significant agricultural lands within the favorable climatic codes for rainfed wheat cultivation. Around 52% of the agricultural lands within these countries are within the climatic codes 3702, 2702, 2802, and 4602. France, Germany, Britain, Poland, and Denmark possess the highest potential to expand rainfed wheat cultivation areas within these favorable climate codes, with respective areas of 2.7, 2.6, 1.6, and 0.9 million hectares. According to the study, the North China Plain emerges as a primary region for increasing irrigated wheat production, both in terms of cultivated area and yield potential. For rainfed conditions, the European continent stands out as a significant region to enhance wheat production.

Seed size, sowing depth, and seed disinfection can affect seed germination and seedling establishment, which, in turn, can directly affect crop growth and yield. The current study was comprised of two experiments, the first of which was conducted in the laboratory, and a second which was performed under glasshouse conditions. The objective of these experiments was to investigate the effects of seed size, sowing depth, and seed disinfection on seed germination and initial seedling growth of selected wheat (Triticum aestivum L.) cultivars. The treatments in laboratory experiment were arranged in a completely randomized design, which included: (Ι) four wheat cultivars (Pishgam, Haydari, Soissons, and Mihan), (ΙΙ) two seed size classes (x < 2.25 mm, and x > 2.25 mm), and two disinfection treatments (no-disinfection and disinfection), (ΙΙΙ) with five replicates. In addition to the aforementioned treatments, the effect of planting depth (4, 6, and 8 cm) was also investigated in the subsequent glasshouse experiment. The best results were obtained at a sowing depth of 4 cm, in the non-disinfected treatment, using large seeds. In contrast, the lowest percentage and speed of seed germination and vigor index were observed in seeds sown at 8 cm depth, in the disinfected seed treatment, using small seeds. Large seeds contain larger nutrient stores which may improve seed germination indices, which would therefore result in improved percentage and speed of seed germination, followed by faster coleoptile and seedling growth, higher seedling dry weight and seed vigor. These data also illustrated that seed disinfection in the Pishgam and Haydari cultivars had inhibitory effects upon coleoptile growth and seedling length, which could be related to the fungicide’s chemical composition. Unlike other cultivars, disinfection did not show a significant effect on the Soissons cultivar. Based on our data, in order to improve both the speed of wheat seed germination and subsequent plant growth and development; it is necessary to select high-quality, large seeds, planted at a specific planting depth, which have been treated with an effective disinfectant; all of which will be specific for the wheat cultivar in question. Overall, the current study has provided useful information on the effect size seed, sowing depth, and disinfection have upon germination characteristics and seedling growth of wheat cultivars, which can form the basis for future field scale trails.

Soil information is a vital input for crop models applications in various large area studies including climate change impact and food security. One of the global soil databases that provide full information for crop models is HC27 of IFPRI. The quality of the database has not been assessed for crop modeling so far. A tested crop simulation model (SSM-iCrop2) was used for this purpose that needs soil water related properties (i.e., depth, albedo, curve number for runoff, drainage coefficient, and soil water limits at saturation, drained upper limit and lower limit) for the simulation of crop properties. Actual data of two soil profiles from three different climate zones (locations) were used as model inputs to simulate potential yield, evapotranspiration (under rainfed conditions) or net irrigation water requirement (under irrigated conditions) of some important plant species (alfalfa, sugar beet, sugar cane, wheat, olive, soybean, apricot and chickpea) under rainfed and irrigated conditions of Iran. Results showed that the application of HC27 soil information in the SSM-iCrop2 model resulted in model output that was not different from the model output with actual soil information with respect to mean, variance, and distribution. No statistically significant difference was found in the simulation of various combinations of soil profiles-plant species-locations. It was concluded that HC27 information can be used in simulation studies with SSM-iCrop2 or other similar simple models for the simulation of potential yield, net irrigation water, or evapotranspiration that are commonly required for food security and climate change studies.