The Effect of Different Amounts of Irrigation and Planting Methods on Water Use Efficiency, Grain Yield and Some Physiological and Biochemical Traits of Wheat (Triticum aestivum L.)

This research was conducted at the research field of West-Azerbaijan (Saatloo station, 45° 10′ 53˝ E/ 37° 44′ 18˝ N and 1338 m above sea level), located 25 km from Urmia city (Iran) during 2019-2020 cropping seasons, as a factorial layout based on randomized complete block design with three replications. The first factor was irrigation regime at three levels (supplying 100, 75 and 50% of net irrigation requirement) and the second factor was planting method of wheat at four levels (plot planting, planting three lines on the ridges (ridges width=30 cm), planting four lines on the ridges (ridges width=45 cm) and planting five lines on the ridges (ridges width=60 cm)). The results showed that the highest grain-yield’s water use efficiency (1.38 kg m-3), dry mass water use efficiency (3.22 kg m-3), carotenoid content (1.02 mg g-1 fresh leaf weight), chlorophyll ratio a to b (3.52) and grain protein percentage (9.89%) were obtained from supplying of 50% of net irrigation water requirement. But the maximum grain yield (7093.30 kg ha-1) and dry mass (15282 kg ha-1), chlorophyll a (1.59 mg g-1 fresh leaf weight), chlorophyll b (0.56 mg/g fresh leaf weight), total chlorophyll a and b (2.15 mg g-1 fresh leaf weight) and protein yield (806.85 kg ha-1) were obtained from supplying of 100% of net irrigation water requirement. Planting three lines on the ridge increased grain yield, dry mass, flag leaf area, grain-yield’s water use efficiency, dry mass water use efficiency, carotenoid content, photosynthetic pigments and protein yield by 29, 33, 31, 29, 33, 38, 7 and 35%, respectively. In general, based on our findings in this study, planting the wheat on the ridge was superior to the traditional method in terms of grain yield and water use efficiency. Also, reducing irrigation water consumption by up to 50% of net requirement did not cause a significant difference in grain yield and dry mass. Therefore, in order to save water consumption and improve water use efficiency, supplying of 50% of net irrigation water requirement along with planting three lines on the ridge is recommended.