Effect of Time and the Foliar Spray of Plant Growth Regulators on Physiochemical Characteristics and Yield of Jujube (Ziziphus jujube)

Jujube (Ziziphus jujube) is widely cultivated in Southern Khorasan province. The tree is adapted to arid and warm regions. This study was conducted as factorial experiment based on a randomized complete blocks design with three replications. In this study, gibberellic acid (GA3), naphthalene acetic acid (NAA) and 6 - benzyladenine (BA) each with five concentrations (0, 20, 40, 60, 80 ppm) alone and in combination with each other were sprayed at three different times full bloom, full bloom 50 days after full bloom and 50 days after full bloom on jujube. The results showed that the spray at full bloom and full bloom 50days after full bloom caused significant increase in fruit size (length and diameter), fruit weight, yield and total soluble solids compared to spraying in 50days after full bloom. Applying concentrations above 40 ppm with GA3, NAA and BA NAA GA3 caused significant increase in fruit size (length and diameter), fruit weight, yield and TSS compared to the control (0 ppm) and all BA concentrations. Foliar spraying plant growth regulators had not significant effect on the other chemical properties of fruit (vitamin C, pH, acidity and the amount of carotenoids).