Due to the construction of dams in upstream countries and the usage of surface irrigation systems, Iraq has been experiencing a water shortage. Due to population increase and the expansion of the industrial and agricultural sectors, the country is having difficulty keeping up with the rising demand for water. Many previous studies carried out to optimize the water resources management in Iraq over the two decades using Water Evaluation and Planning (WEAP) modeling considering various aspects and different water resources throughout Iraq provinces. This study aims to find out if the WEAP modeling is reliable to optimize water resources management, fourteen previous studies were reviewed to figure out the fields they focused on, the study limitations, and the obtained results. It was found that the WEAP model is reliable for assessing, planning, and optimization of water resources management.

Two field experiments were conducted during spring and autumn season of 2020, which were carried out at the Research Station of the College of Agriculture, Anbar University, in the first season The lines were introduced into the Half Diallel cross-program according to the second method proposed by [24]. the second season the experiment was applied during the autumn season of 2020 in a split-block arrangement according to a randomized completely -block design with three replications. The main block included the plant density, which was expressed through the distance between the holes. While the secondary block occupied the genotypes (lines + crosses). The results of the analysis showed that there were significant differences between densities and genotypes.The cross 3 × 5 was distinguished by giving the least number of days to tasseling. It also gave the highest plant height 188.60 cm, number of rows / heads 15.5, and the highest yield 19.54 tons / hectare. The cross 1× 5 showed the highest leaf area 5925 cm, while the cross 4×5 and 3×4 showed the highest average number of kernels / row 39.33 and 38.97. The cross 1×4 also distinguished with the highest weight of 300 grains. Cultivated plants with a density 62,500 plants / hectare were distinguished by giving them the fewest days to flower, the highest plant height, leaf area, number of rows, number of grains / row and weight of 300 grains. While the yield was low at 14.93 compared to the plants that cultivated at a density of 125,500 plants / hectare, the reason for this is that the increase in the number of plants per unit area was replaced by the decrease in the yield components.