Effects of exogenous TIBA on dwarfing, shoot branching and yield of tea plant (Camellia sinensis L.)

2,3,5-Triiodobenzoic acid (TIBA) is a safe and efficient synthetic auxin transport inhibitor. The mature tea plants of the cv. Longjing 43 were used in this study. The foliar portion of tea bushes were sprayed with different concentrations (50, 100, or 150 mg L-1) of TIBA after heavy pruning (i.e., after two to three leaves grew out in late May). The effects of TIBA on the growth of the new shoots and lateral branches were explored. After 5 months, treatments with 50, 100, and 150 mg L-1 TIBA decreased plant height by 13.5%, 22.9%, and 23.3%, respectively; TIBA at 50, 100, and 150 mg L-1 decreased the number of lateral branches by 18.0%, 18.6%, and 8.4%, respectively. Treatments with 100 mg L-1 TIBA increased the length of lateral branches by 34.3%; 50 and 100 mg L-1 TIBA increased the lateral branch diameter by 9.45% and 12.46%, respectively. After 2 months, 50 and 100 mg L-1 TIBA did not significantly affect photosynthetic rate in comparison with the control. Furthermore, 106 mg L-1 TIBA significantly increased spring tea yield by 19.3% in comparison with the control. In conclusion, the treatment of 100 mg L-1 TIBA can promote dwarfing, and formation of effective lateral branches, and spring tea yield. It is suggested to spray `Longjing 43' tea plants with 100 mg L-1 TIBA solution after heavy pruning in summer (i.e., after two to three leaves grew out in late May).