Physiological Disorders In Grafted Heirloom Tomatoes Grown In High Tunnels Using Organic Production Practices

A systems comparison study was conducted to evaluate two scion-rootstock combinations and a non-grafted control, grown in both an organic high tunnel and open field system. ‘Cherokee Purple', an heirloom, susceptible to cracking and cat-facing (rough fruit) was grafted on ‘Maxifort' and ‘Beaufort' rootstocks. The study was conducted in 2007 and 2008 at The Center for Environmental Farming Systems (CEFS) in Goldsboro, North Carolina.  Over both seasons, total fruit production was greater in the high tunnel system compared to the field system. High tunnel planting dates were approximately 1 month earlier and resulted in peak harvests 21 days earlier compared to the field system. Fruit quality measured by the number of fruit with cat-facing, cracking, blossom-end rot, sun-scalding, insect damage or other defects showed differences among the systems. In particular, insect damage was greater in the field system while cat-facing and blossom-end rot were greater in the high tunnel system. In 2007, marketable fruit yields were greater in the high tunnel system compared to the field system but the opposite was true in 2008.  In the second season with improvements to the irrigation management, fruit cracking was considerably decreased in the high tunnel system. We had expected greater fruit quality from tunnel production but both blossom end rot and cat-facing caused large number of defects in the high tunnel system. The effects of environment and watering on the incidence of defects will be discussed.