Original Article | 2005, Vol.27 Supplementary III: PSU. Open Week, pp.683-690
Effect of chemical application on vegetative growth of longkong.
Monsuang Ruangkhanab and Mongkol Sae-Lim
pp. 683 - 690
Abstract
The first bearing time of longkong tree is long due to the long juvenile period. A feasibility study on longkong root and leaf growth acceleration by chemical application to alleviate this problem was conducted through 2 experiments: 1) Fifteen one-year old of longkong seedlings were used and each seedling was grown in a 24 litre-pot. All plants were treated with 5 g/plant of 15-30-15 fertilizer, plus 18 ml/plant of humic acid at 3 and 5 week intervals to accelerate root growth and compared with controls (no fertilizer). 2) Four-year old longkong trees propagated by cuttings (18 plants) were grown in 50 litre-pots and foliar chemical substances were sprayed for shoot acceleration. There were 6 treatments 3 replications in the experiment: 1 ppm carboka®, 400 and 700 ppm thiourea, 400 and 700 ppm BA twice at 3-week intervals and control. The results indicated that 5-week interval treatment showed highest fresh and dry weight of leaves and roots, and root length. Furthermore, it also induced high compound leaf number, leaf area and height. The result of foliar chemical spraying revealed that 1 ppm carboka®, 400 ppm thiourea and 400 ppm BA treatment induced the greatest branch number and 1 ppm carboka® spraying showed a higher number of compound leaves than the control. The 700 ppm of thiourea application gave the highest longkong leaf area. It is suggested that the optimum period and quantity of fertilizer and plant growth regulator applications can efficiently manipulate the growth of longkong plant .
