Effect of irrigation cycle and foliar application of titanium in both forms of nanosized ‎and bulk on growth traits and yield of Rosa × damascena Mill‏.‏‎ ‎

Drought is one of the major factors limiting horticultural products and this is more important in arid and semi-arid regions. Due to the importance of nanotechnology in improving the methods available in horticulture, this experiment was performed on Rosa × damascena Mill as factorial experiment based on the completely randomized design with three replications at Faculty of Agriculture, Ferdowsi University of Mashhad, in the growing season of 2018. The treatments consisted of 2 irrigation regimes (3 days and 6 days) and 5 levels of titanium (0 (control), 15 and 30 ppm titanium dioxide, 15 and 30 ppm nano-titanium dioxide). The results showed that with increasing the irrigation interval, decreased leaf area and flower diameter. Titanium was affected on flower diameter, peduncle diameter and length of peduncle at all levels. Number of flowers increased by 15 and 30 ppm titanium dioxide 40.8 and 54.9%, respectively, and with 15 and 30 ppm nano-titanium dioxide 84 and 69%. In treatment of 30 ppm nano-titanium dioxide and irrigation interval 3 days, the amount of proline was 0.20 and in the same treatment of titanium and irrigation interval 6 days, was equal to 0.50 µmol/g. In general, the use of titanium dioxide and nano titanium dioxide resulted in improved growth traits and flower diameter. Also, among the used levels, 15 ppm nano-titanium dioxide had a greater effect on flower diameter, flower number, relative water content, and spade.