Temperature makes the difference: improving tomato seedling survival during transport

2 Every year millions of grafted seedling tomato plants are loaded into refrigerated trucks and shipped to greenhouses in Arizona, Texas and other states. Grafted seedlings combine high-producing tomato varieties with diseaseresistant rootstocks. Although the demand is high, the production of these high quality transplants is not yet widespread in the United States. Rather, greenhouse producers purchase them from specialty propagators in Canada. The drawback is that the stress of the long-haul trip can weaken the plants and cause them to yield poorly after they are transplanted into hydroponic systems (where plants are grown in nutrient solutions). Their maturity may be delayed, affecting the size and number of fruit produced. Not only has the production of high quality transplants become a critical technology that supports the success of the final crop, the way they are transported makes a difference as well. Two researchers at the UA’s Controlled Environment Agriculture Center (CEAC) in Tucson are working with a Canadian transplant propagator and an Arizona greenhouse producer to learn more about how to reduce the failure rate in transporting tomato seedlings over long distances. Although these grafted transplants, which cost $1.00 to $1.50 per plant, are considerably more expensive than the bare-root seedlings typically used for field-grown tomatoes, the researchers say not much information is available on the best conditions for transporting them. The Arizona Department of Agriculture has funded the research. “The goal was to understand how to optimize transportation conditions,” says Chieri Kubota, associate professor of plant sciImproving tomato seedling survival during transport