Effects of Paclobutrazol on the Growth of Marang (Artocarpus odoratissimus) Seedlings

Shorter trees are ideal in tree orchards for ease in harvesting which will increase fruit recovery and yield. In the Philippines, marang has been considered a potential crop to help food security. However, the crop can grow very tall which would make fruit harvesting tedious. This study was conducted to determine if paclobutrazol (PBZ) at concentrations of 0, 250, 500, and 1000 ppm applied as a media drench could regulate the growth of marang at the seedlings stage. Results showed that paclobutrazol treatment reduced the leaf size of 110-day-old seedlings almost four-fold compared to the non-PBZ-treated (control). The stomatal density of the leaf in 250, 500, and 1000 PBZ-treated seedlings was 8.51, 8.49, and 8.11 mm-2 compared to only 5.62 mm-2 in the control respectively. Closed stomata in 250, 500, and 1000 ppm PBZ-treated seedlings were 2.78, 2.49, and 3.24 mm-2 compared to 1.33 mm-2 in the control respectively. The 250 ppm PBZ treatment increased the chlorophyll index (489.08) of the Marang leaf compared to the control with 256.58. The shoot and root lengths of seedlings were reduced five-fold and 42.35-52.23% by paclobutrazol treatment respectively. The control seedlings' fresh weight (18.33 grams) was nearly five-fold heavier than the PBZ-treated seedlings. The shoot-root ratio of the control seedlings was three-fold higher than the PBZ-treated seedlings. On the other hand, PBZ treatments resulted in a three-fold increase in root-to-shoot ratio. These results are useful in the production of shorter marang trees with longer roots to ease managing the crop in the field.

Effects of Paclobutrazol on the Growth of Marang (Artocarpus odoratissimus) Seedlings Keywords:

Bonsai , Growth retardant , plant growth regulator , triazole , Underutilized fruit species