Economic Analysis of Pruning Grafted Fresh-market Tomato Plants under Field Conditions in North Carolina

Abstract

Grafted tomato (Solanum lycopersicum L.) plants have the potential to increase yield in the absence of soilborne disease; however, success is dependent on geographic location and rootstock–scion combination. Pruning axillary shoots on field-grown tomato plants is a standard practice for fresh-market production in the southeastern United States, although few studies have evaluated the effects of pruning grafted tomato plants. In this study, we evaluated six field grown tomato rootstock–scion combinations and their nongrafted counterparts, pruned or not pruned, over the course of 2 years at one location in North Carolina. Total yield, fruit size, variable cost of inputs, and net return data were analyzed. In both years of the study, cultivars Mountain Gem and Jolene had high yield of jumbo and extra-large fruit when grafted onto ‘Maxifort’ or ‘Beaufort’ rootstock. Yield was higher (P < 0.0001) for plants that were grafted and not pruned compared with nongrafted pruned plants (grower standard). Net return from the treatment where plants were grafted onto ‘Maxifort’ rootstock and not pruned was greater than that from the grower standard practice, although this was not the case in both years of the study. The variable cost of growing grafted plants that were not pruned was always greater than that of the grower standard practice due to the greater cost of transplants and labor associated with harvest. The results from this study emphasize the importance of evaluating a small number of prospective rootstock–scion combinations on-farm and considering the balance between higher input costs of the grafted plants and potential increased yields before planting an entire field.