Study of Different Aged Jackfruit (Artocarpus heterophyllus L.) Rootstocks on Softwood Grafting Success under Different Environmental Conditions

Abstract

An investigation was conducted to find out the optimum Jackfruit rootstock age for softwood grafting and to find out the suitable environmental condition for the success of Jackfruit grafts was conducted at Department of Biotechnology and Crop Improvement, College of Horticulture, Kolar, Karnataka during the year 2023. Six different aged Jackfruit rootstocks (15, 30, 45, 60, 75 and 90 days old) were softwood grafted and evaluated under three environmental conditions (Shadenet, Polytunnel and Polyhouse) in a factorial completely randomised design with four replications. The morpho-physiological results revealed that, 15 days old rootstock grown under shadenet took highest number of days for sprout initiation (24.02 days) compared to others. Significantly highest graft success (50.20 %) was recorded in 90 days old rootstock grafts grown under polyhouse condition 30 days after grafting. Maximum number of leaves per graft (4.95, 6.95 and 9.15) and maximum RWC % (83.63, 86.98, and 90.61 %) was recorded in 90 days old rootstock grown under polyhouse at 30, 60 & 90 days after grafting respectively. Similarly, significantly highest chlorophyll (4.70 mg/g FW), root length (18.52 cm), root fresh weight (9.43 g/plant), root dry weight (1.35 g/plant) and root biomass (3.64 g/plant) found in 90 days old rootstock grafts grown under polyhouse conditions. The maximum root-to-shoot ratio was recorded on fresh weight (0.73 g) and dry weight (0.56 g) in 90 days old rootstock grown under polyhouse condition. Significant maximum graft survival (44.71 %) recorded in 90 days old rootstock grafts grown under polyhouse. Significantly highest graft dry matter (3.95 g/plant) was recorded in 90 days old rootstocks grafts grown under polyhouse whereas least in shadenet (2.99 g/plant). In conclusion, it is found that grafting of 90 days old Jackfruit rootstocks performed better under polyhouse conditions for most of the traits.