Optimizing the Time of Grafting in Jackfruit in the Subtropical Environment of Assam

An experiment was carried out at the instructional cum research farm, Department of Horticulture, BNCA, AAU, Biswanath Chariali during 2019-2020. The objective of the experiment was to check the best time of wedge grafting in Jackfruit in the subtropical conditions of Assam. A total of seven treatments were taken, viz. Grafting in March (T1), April (T2), May (T3), June (T4), July (T5), August (T6), and September (T7). Six to seven months old, vigorously growing uniform seedlings of Jackfruit grown from the seeds were selected as rootstocks. Mother plants of desirable traits were selected for the experiment. Scions of about 10-15 cm in length with a thickness of 5-7 mm and free pests and diseases were collected from one season (4-5 months) old terminal shoots. The selected scion shoots were defoliated (pre-cured) 7-10 days before grafting. Wedge grafting was adopted in the present study. Further, wedge grafting was performed with compatible rootstocks in the different months stated above and conclusions were made that the period from March to June could be considered as the suitable time for producing jackfruit grafts by wedge grafting method in Assam. March and April are the best months for grafting jackfruit, as weather conditions in terms of temperatures with daily maximum (21.1 -35.6°C) and minimum temperature (8.3 to 23.0°C), rainfall more than 100 mm, comparatively higher bright sun-shine hours are congenial from the success of grafting in terms of success percentage of stock and scion union, the time required for spouting, several buds developed and length of the scion on 90 days after grafting. While the temperature gradually rose from June onwards up to September and there was also quite a reduction in the amount of rainfall, due to which the moisture content present in the leaves of the scions dried up because of evapotranspiration and decreased in the percentage of graft success.