Effect of Cutting Timing and Various NAA Hormone Concentrations on Rooting Success of Local Zarak Grape Cuttings (Vitis vinifera L.)

The study investigates the impact of cutting timing and varying concentrations of Naphthaleneacetic acid (NAA) on the rooting success of Zarak grape cuttings (Vitis vinifera L. (Conducted in greenhouses at the Agricultural Technical College of the Northern Technical University in Mosul, the experiment utilized woody cuttings from the Zarak variety, a popular local cultivar. The cuttings were prepared and treated with NAA at concentrations of 100 and 200 ppm, alongside a control group with distilled water. The cuttings were planted on two different dates: February 25 and March 25, 2024, with careful monitoring of rooting responses. Statistical analysis was performed using a complete randomized design (CRD) and ANOVA to assess the effects of NAA concentration and planting date on rooting characteristics. Results indicated that higher NAA concentrations significantly improved rooting success compared to the control. Specifically, at the first planting date, NAA concentrations of 100 ppm and 200 ppm yielded the highest root lengths (8.25 cm and 8.00 cm, respectively), while the control group recorded only 5.50 cm. The second planting date also showed improved results with 200 ppm NAA achieving the highest root length of 8.50 cm. On the other side of the study, the characteristic of the number of radicals, it is also noted that the hormone interference treatment NAA 200 pmm is superior to the control treatment at the first date and zero NAA, so the values reached 73.25 and 25 respectively at the first date of transplantation. While the first appointment recorded a significant superiority over the second appointment 53.41 and 45.08, as well as the superiority of the hormone coefficient 200 NAA for the first appointment over the witness The findings suggest that NAA enhances root development by promoting cell elongation and nutrient absorption, which is crucial for successful rooting The increased number of roots may be due to the effect of auxin, which enhances cell division and elongation, root differentiation, and its role in mobilizing reserve nutrients to the root initiation sites, thus producing a greater number of roots per cutting (Chakraborty & Rajkumar, 2018).