Effect of paclobutrazol and hydrogen peroxide on growth, quality and yield of melon fruit (Cucumic melo cv. khatooni)

In order to investigate the effect of plant growth regulator paclobutrazol and hydrogen peroxide on growth, yield and fruit quality of melon (cv. Khatooni), the experiment was set out in a randomized complete block design with three replications in the research farm of University of Zanjan. Treatments include pruning (control), thinning, three levels of hydrogen peroxide (2.5, 5 and 7.5 mM) and paclobutrazol at three levels (10, 20 and 30 mg.L˗1) in 4 -6 leaf and fruit set stages. The result showed that foliar application of hydrogen peroxide increased the total soluble solids content. Thinning treatment had no significant effect on growth and fruit quality but increased yield compared to the control plants. Foliar application of paclobutrazol reduced growth and increase yield fruit and total soluble solids content compared to the control plants. According to result, the highest fruit weight, fruit yield and total soluble solid and the lowest number of stem and plant length was obtained with application of paclobutrazol 10 mg.L˗1 at 4 to 6 leaf stage, so foliar application of paclobutrazol (10 mg.L˗1 at 4 to 6 leaf stage) can be proposed instead of plant thinning practice that require too much time and labor for the farmers. Also hydrogen peroxide 7.5 mM increased dramatically total soluble solids contents, sucrose and fructose that it is recommended to improve quality of melon fruit.