ผลของการให้ปุ๋ย ขนาดหัว และการพรางแสงต่อการเติบโตและการสร้างหัวของทิวลิป

Abstract

The effects of bulb size, fertilizer application and shading on growth and bulb formation of tulip were carried out in 2 experiments. The experiment was conducted from November to December 2020 under average temperature 25.76 'C and relative humidity 57.7 percent. Experiment 1: Studied on the effect of fertilizer formula, fertilizer rate and bulb size on growth and new bulb yeild of tulip 'Strong Gold'. The experimental design was Factorial in CRD. Plants were supplied with 3 factors, i.e: 1) four types of fertilizer formula (15-15-15, 18-46-0, 13-0-36 and 0-52-34) 2) three levels of fertilizer rate (4, 8 and 12 g/m') and 3) two levels of bulb sizes (large bulb was 8.0 - 10.0 cm circumference and small bulb was 6.0 - 7.9 cm circumference) with 24 treatments and 10 replications (1 bulb per replication). The result showed that plants supplied with fertilizer formula 18-46-0 shows the highest of plant height, photosynthetic rate, circumference of new bulb, fresh and dry weight of new bulb. Growing with large bulb size showed higher of vegetative growth, photosynthetic rate and bulb quality after harvesting than small bulb size. Growing with 4 and 8 g/m fertilizer application showed the highest of plant height and photosynthetic rate. The results of the interaction were found between fertilizer formular 18-46-0 with the rate of 8 g/m2. Using large bulb brought about the best vegetative growth and quality of new bulb. Experiment 2: effects of shading on growth and bulb quality of tulip 'Strong Gold' were studied. Plant were grown under three levels of net shading i.e., 1) no shading (under 568.67 umol m' s' of light intensity), 2) 50% of net shading (with 388.09 umol m's' of light intensity) and 3) 70% of net shading (with 100.09 umol m's'of light intensity). The experiment was conducted at Hod district, Chiang Mai province (1,400 m above sea levels, 25.4 'C and 63.9 % RH). The experimental design was completely randomized design (CRD) with 3 treatments and 20 replications (1 bulb per replication). Plant height, number of leaves per plant, SPAD unit, photosynthetic rate, stomatal conductance, transpiration rate, bulb fresh and dry weight, number of new bulbs per plant, and total non-structural carbohydrate (TNC) were measured. The results found that at plants grown under 50% net shading had the highest TNC content, fresh and dry weight of bulb (227.1 mg/bulb, 9.37 and 3.01 g, respectively). Number of new bulbs were not significant difference among treatments. Therefore, 50% net shading might be suitable for growing tulip in Thailand.