Fig 1.
The map highlights the countries which have utilized the Global Yield Gap Atlas (https://www.yieldgap.org) to calculate the potential yield, actual yield, and yield gap for wheat, and they are marked in green.
A total of 49 countries have extracted this information according to the GYGA protocol. Major wheat production areas were obtained from GYGA website.
Fig 2.
Worldwide cultivation area of irrigated wheat.
In this map areas with higher cultivation levels are shown in dark brown and areas with less cultivation levels are exhibited in yellow color. Irrigated wheat cultivation areas were obtained from SPAM 2010.
Table 1.
Harvested area, actual yield, actual production, potential yield, potential production, yield gap, and production gap in the main countries producing irrigated wheat.
The data used in this study was obtained from the GYGA and MapSpam websites in 2022. The GYGA dataset covers the last 15 years for rainfed condition and 10 years for irrigated condition.
Fig 3.
Worldwide actual yield (A), potential yield (B) and yield gap (C) of irrigated wheat. In 3A and 3B, the highest and lowest actual and potential yield values are shown in green and red color, respectively. In 3C, on the contrary, the highest values of production gap are shown in red color and the lowest values are exhibited in green color. The actual yield of irrigated wheat (A) was obtained from SPAM 2010 and the potential yield (B) of irrigated wheat was retrieved from GYGA website.
Fig 4.
Worldwide actual production (A), potential production (B) and production gap (C) of irrigated wheat. In 4A and 4B, the highest and lowest actual and potential yield values are shown in green and red color, respectively. In 4C, on the contrary, the highest values of production gap are shown in red color and the lowest values are exhibited in green color. The actual production of irrigated wheat (A) was obtained from SPAM 2010 and the potential production (B) of irrigated wheat was retrieved from GYGA website.
Fig 5.
This map displays the global cultivation area of rainfed wheat, with darker shades of brown indicating regions of higher cultivation and lighter shades of yellow indicating lower levels of cultivation.
Cultivation area of rainfed wheat was retrieved from SPAM 2010.
Table 2.
Summarizes information on rainfed wheat production in major producing countries, including the size of cultivated land, actual and potential yields, actual and potential production, as well as the yield and production gaps.
The data used in this study was obtained from the GYGA and SPAM websites in 2022. The GYGA dataset covers the last 15 years for rainfed condition and 10 years for irrigated condition.
Fig 6.
The figures display the actual yield (A), potential yield (B), and yield gap (C) of rainfed wheat worldwide. The highest and lowest values for actual and potential yield are represented in green and red, respectively, in 6A and 6B. Conversely, in 6C, the highest production gap values are highlighted in red, while the lowest values are indicated in green. The actual yield of rainfed wheat (A) was retrieved from SPAM 2010 and the potential yield (B) of rainfed wheat was obtained from GYGA website.
Fig 7.
The figures present information on the global production of rainfed wheat, including actual production (A), potential production (B), and the difference between the two (C) referred to as the production gap. 7A and 7B highlight the maximum and minimum actual and potential yields, which are represented in green and red colors respectively. 7C, on the other hand, displays the highest production gap values in red and the lowest in green. The actual production of rainfed wheat (A) was retrieved from SPAM 2010 and the potential production (B) of rainfed wheat was obtained from GYGA website.
Fig 8.
These charts display how the actual yield (Ya) and potential yield (Yp) values vary with the growing degree-day index (A & B) and temperature seasonality index of climate zone code (C & D). A boundary line representing the function fitted maximum yields is shown in black. The data pertains to an irrigated condition.
Fig 9.
The comparison of real crop yield (Ya) and the maximum yield potential under limited water supply (Yw) in relation to the growing degree-day index (A, B), aridity index (C, D), and temperature seasonality index (E, F) of various climate zones. The black line represents the fitted function boundary line, indicating the maximum possible yield. This comparison is made under rainfed conditions.
Table 3.
The optimum range of GDD, aridity index, and temperature seasonality for wheat production under irrigated and rainfed conditions.