The Horticulture Innovation Lab, Kasetsart University-Kamphaeng Saen (KU-KPS), and WorldVeg East and Southeast Asia in Thailand hosted a vegetable grafting workshop on 22-23 February 2017 for 30 participants from the private seed and nursery sector from Thailand, Cambodia, India, and Lao PDR.

As part of the program field experiments from Honduras, Guatemala, Taiwan and USA were presented, reviewing different rootstock and scion combinations under different climatic conditions.

After the welcome address given by Jingtair Siriphanich, Head of the Tropical Vegetable Research and Development Center (TVRC), KU KPS Department of Horticulture, Somchit Pruangwitayakun from the World Vegetable Center officially opened the workshop by giving an overview of grafting and the Center’s activities. Chumnong Somkul from TVRC gave an introduction to vegetable and tomato production in Thailand. Matthew D. Kleinhenz from Ohio State University, Willie Chen from WorldVeg, and James Nienhuis from the University of Wisconsin-Madison gave presentations on vegetable grafting experiences in the US, Taiwan, and Central America, respectively. Marti Pottorff from WorldVeg shared results of flooding tolerance experiments with grafted tomato conducted by Ellen Iramu and her colleagues in the Solomon Islands.

Workshop participants practiced how to cut grafting tubes and do tomato grafting. They also learned how to build and use a low cost healing chamber, which creates a dark, cool and humid atmosphere that encourages the graft to heal. The participants also visited an ongoing grafted tomato experiment in the WorldVeg East and Southeast Asia demonstration garden.

Seed companies in Thailand are using grafting for seed production of tomato, and some small-scale seedling nurseries also are producing grafted plants.

“In general, there is a risk to grafting,” said Willie Chen, WorldVeg Postdoc in Agronomy/Plant Protection.  “The irrigation method is important. Splashing may cause soil to settle around the graft union and increase pathogen infection. Farmers need training, and they need to be aware of the importance of adjusting their crop management practices when growing grafted plants.”

Experience from India has shown that grafting works well in tomato under hot weather conditions. A simple healing chamber using cloth instead of a plastic cover can be set up over benches in a greenhouse. A fogging system to mist the plants at short intervals makes the conditions humid and relatively cool.

The Center’s aim now is to coordinate rootstock germplasm evaluation between Southeast Asian and Central American partners, and to do this with a focus on and abiotic stresses, Ralstonia, and other soil-borne pathogens associated with tomato and eggplant production.

Story and photos: Svein Solberg and Willie Chen