2014 Volume 5 Issue 1 Pages 131-135
The experiment of appropriate chemical fertilizer application rates on yield, yield components, dry calyx acid and seed oil contents in red roselle (Hibiscus sabdariffa) cultivar: Surin with 4 chemical fertilizer rates (16-16-16: 0, 25, 50 and 75 kg/rai; 1 rai = 1,600 m2) was conducted at Faculty of Agricultural Technology; Rajamangala University of Technology Thanyaburi; Pathumtani province, during late July to December 2010 by RCB design 4 replications. The results indicated that some agronomic characteristics, yield and yield components of all red roselles with applied in any rate of the chemical fertilizer were higher than the non-applied one. The rate of 75 kg/rai brought red roselle not only got better in growth of vegetative parts (192.2 centimeters of plant height, 10 main branches), faster in 50% first flower blooming date (only 100 days after planting), longer periods of flowering and maturation of the first fruit (22 and 23 days after the first bloom flower) but also gave greater in yield components (38.8 fresh fruits, 179.2 and 24.1 grams fresh and dry calyx , 31.1 grams of seeds/plant), these supported the roselle to get the highest yield (764.8, 103.0 and 132.8 kg/rai of fresh calyx, dry calyx and seed weight respectively). Nevertheless when considering to the harvest index, the highest rate of fertilizer applied roselle plot was equal to that non-applied plot (0.36). Regarding to the analysis of dry calyx acid and seed oil contents in red roselle, all treatments by average contained 13-16% of acid and 20-21% of seed oil.
