تأثير الرش المشترك بأوكسين الـ IBA وهيومات البوتاسيوم في بعض الصفات المؤشرات الفيزيولوجية والإنتاجية لصنف القطن حلب 124

Abstract

This field experiment was conducted at the Jeb Ramleh Research Station in Hama Governorate to study the effect of foliar spraying with Indole-3-butyric acid (IBA) and potassium humate on some physiological and productive traits of the cotton cultivar Aleppo 124 during the 2024 growing season. The experiment was carried out using a randomized complete block design (RCBD) with six treatments and three replications. Treatments included the control (T0S0), three levels of IBA (1, 2, and 4 g/L), and two levels of potassium humate (2 and 4 g/L), applied in three sprays at 45, 65, and 75 days after planting. The results showed significant differences among treatments in all studied traits. The treatment T2S4 (moderate IBA concentration with a high level of potassium humate) recorded the lowest boll shedding percentage (15.4%), representing a 31.6% reduction compared with the control (22.5%). This treatment also achieved the highest seed cotton yield (4.897 kg/plot), the largest leaf area (4200 cm²), and the highest leaf area index (LAI) of 3.80. In addition, treatment T2S4 reduced the height of the first fruiting branch to 32.7 cm, indicating earlier flowering and fruiting, and increased the ginning outturn to 39.8% compared with the control. These improvements can be attributed to the synergistic effect between IBA and potassium humate, as IBA contributed to flower and boll retention by reducing the activity of abscission enzymes and promoting vascular differentiation, while potassium humate enhanced nutrient uptake—especially potassium—thus improving photosynthetic efficiency and assimilate translocation to developing bolls. The study concluded that treatment T2S4 (2 g/L Indole-3-butyric acid with 4 g/L potassium humate) is the most suitable for increasing cotton productivity and improving its quality traits under the experimental conditions, and it is recommended as a practical strategy for enhancing cotton production under similar environmental conditions.