Effect of gibberellic acid and zinc sulphate on vegetative, flowering, seed yield and chemical consistent of jojoba plant (Simmondsia chinensis)

Abstract

This experiment was conducted to study jojoba response (Simmondsia chinensis) evergreen dioecious shrub to zinc sulphate plus gibberellic acid foliar application on vegetative, flowering, seed yield and seed chemical composition at private farm during two successive seasons of 2015 and 2016 in the Egypt. An experiment was laid out in randomized complete block design with three replications. In this study, jojoba plants were sprayed with all combination treatments of zinc sulphate (0, 25, 50 and 75ppm) plus gibberellic acid (0, 50, 100 and 150ppm) thrice in the beginning of December, March and May. There results revealed that all combination treatments showed a significant improvement in all examined parameters with an increase in ZnSO4 / GA3 levels in comparison with untreated trees. Therefore, the maximum significant branch length (99.36 and 103.46 cm), secondary branches length (55.82 and 58.36 cm) obtained by application of 75ppm ZnSO4 plus 150ppm GA3 treatment, so this combination recorded the highest percentage of flowering %, final fruit set (95.01, 95.24%), total chlorophyll, mineral% content, seed yield per feedan (2200, 2145 kg) and seed lipid content(57.6%, 58.55%) at first and second terms respectively. The application of 75ppm ZnSO4 plus 150ppm GA3 treatment is recommended to improve jojoba traits which lead to raise its economic value as a promising tree which potentially useful as a biofuel with multi chemical and pharmaceuticals industries uses.