Water-Yield Relation of Deficit Drip Irrigated Cotton Cultivars in a Semi-arid Environment

This study was carried out the May 455, Sasha-09 Sahra and Özaltın 404 cotton cultivars in 2024 at the Research and Application Farm of the Agriculture Faculty of Aydın Adnan Menderes University, Aydın-Türkiye. The applications of water significantly affected seed cotton yield. A randomized complete block design was used with three replications and two factors. Irrigation was begun in the control plots (IR-100) with 40% of available water holding capacity of the soil at a depth of 0.90 m taken up, and 50% of the water applied to the control plots was applied to the other plot. Seasonal crop water use varied between 449 and 788 mm according to cultivars. The highest average seed cotton yield was obtained from IR-100 treatment as averaging 435.9 kg/da. The lowest yield was obtained from IR-50 treatment as averaging 323.5 kg/da. Examining these results from the point of view of varieties, it is seen that May-455 formed the first group and the Özaltın-404 the last group. Average WUE values varied between 0.528 and 0.766 kg/m3. According to growing year, the yield response factor (ky) was found to be 0.55 (May-455), 0.70 (Sahra), 0.64 (sahra-09) and 0.63 (Özaltın-404). It may be concluded that the treatment which gave the best performance whether for high seed cotton yield was treatment IR-100 when the water source was not limited and it completely met the irrigation water needs of the crop. On the other hand, treatment which gave the best performance whether for water saving or for high water use efficiency was treatment IR-50 treatment if irrigation water in the area was limited and water was applied at a rate of 50%.