Effect of Paclobutrazol on Growth of ‘Lueng Krabi’ Papaya Grown in Pot

Abstract

    Papaya is a rapidly grown plant. This is uncapable to be used as a potted plant. Therefore, paclobutrazol (PBZ) was applied to ‘Lueng Krabi’ papaya plants grown in 10-inch pots to determine the amount of PBZ suitable for retarding the growth. A completely randomized design was used with 10 replications, 1 for each plant. PBZ was applied to the papaya plants by soil drench at the amounts of 0, 2, 4, 6, 8 and 10 mg (a.i.)/plant for 2 times, in which the first time was applied at the age of 45 days after transplanting and the second time was applied at 90 days after the first time. The papaya plants were measured for stem height, canopy height, stem diameter, internode length, petiole length during PBZ application and for stem fresh weight, root fresh weight, leaf fresh weight, leaf area and SPAD unit after the second time of PBZ application for 13 weeks. The results showed that plants treated with PBZ were shorter in new internode length and lower in root fresh weight (P ≤ 0.05). The other measured characteristics including plant height were no statistically different (P > 0.05) among the treatments. This implied that the PBZ amounts less than 10 mg (a.i.)/plant were insufficient to retard the growth of potted ‘Lueng Krabi’ papayas for decoration uses.