Effect of various concentrations of bio-regulators and time of Air-Layering on the multiplication of Jackfruit (Artocarpus heterophyllus Lam.)

Studies was conducted to find out the effect of various concentrations of IBA, NAA (i.e. 5000, 10000, and 15000 ppm) and Keradix at four times of air-layering operations (i.e. 2-3 July, 25-26 July, 17-18 August, 9-10 September) on the rootability in jackfruit through air-layering. A critical study of present findings show that the treatment of 10000 ppm concentration of IBA was found to produce highest percentage of rooted layers (82.8 %), profuse callus formation, maximum number of primary roots (19.95), longer length of longest root (15.59 cm), thickest diameter of longest root (1.45 mm), maximum percentage of layers showing secondary roots (66.6%), higher fresh (0.924 g) and dry (0.466 g) weight of roots with higher survival percentage (71.37) of layered plants in nursery beds. The best time of air-layering was recorded 2-3 July in respect of higher percentage of rooted layers (73.78), profuse callus formation and maximum weight of fresh (0.808 gm) and dry (0.404 gm) roots, higher survival percentage of layered plants (62.83%) and percentage of plants showing new growth (62.83%), while 25-26 July time of air-layering was found better in relation to maximum number of primary roots (13.68), longest length of root (13.43 cm), diameter of longest root (1.3 mm), higher percentage of layer showing secondary rooting (26.85%), length of new growth (1.87 cm) and number of leaves on new growth (2.05).