Un-rooted grafted cuttings for eggplant plug-transplant production and shipping: simulated transportation and healing requirements

Vegetable grafting is one of the most effective eco-friendly techniques to overcome pests and soilborne diseases in modern cropping systems of fruiting vegetables. Due to the increased farmers’ preference for grafted seedlings of high quality and better performance, the use of vegetable grafted plants is rapidly spreading and expanding over the world and intensive researches on new commercial production systems are under way. However, in many areas of the world, due to the high cost of skilled manpower, the use of grafted plug plants is still limited causing a relatively slow development of the grafting nursery industry. The aim of this work was to evaluate a possible use of un-rooted grafted cuttings as means of propagation and distribution of eggplant transplants. In this experiment, un-rooted grafted eggplant cuttings (‘Birgah’ eggplant scion with Solanum torvum rootstock) harvested after diverse healing times [0 (DIH 0), 1 (DIH 1), 3 (DIH 3), 5 (DIH 5), or 7 (DIH 7) days in healing] were exposed to 20, 14 and 8°C ‘simulated transportation temperature’ and dark condition in a growth chamber for 72 hours. After 72 hours of the simulated transportation treatment, all un‐rooted grafted cuttings were transferred into the greenhouse for rooting. The results showed that S. torvum is a suitable rootstock for applying the un-rooted grafted cutting propagation technique. All grafted cuttings reached the grafting success (100%) and all un-rooted grafted cuttings developed roots at the end of the rooting stage (100%). Regardless of the simulated shipping conditions, the treatment DIH 0 gave the best results in terms of number of leaves after rooting (3.8 leaves), shoot fresh and dry weight after 7 days of growth (3.92 and 0.46 g, respectively), fresh weight of the roots (1.34 g), and plantlet visual quality of the finished plug transplants (8.8). This innovative production/ shipping method might be successfully used in areas where local nurseries do not have high grafting ability.