Vegetable grafting is popular in Asian and European countries where continuous cropping and intensive production is practiced. This technique offers resistance/tolerance to biotic and abiotic stressors in a variety of cucurbitaceous and solanaceous crops (Kubota et al., 2008; Lee et al., 2010; López-Pérez et al., 2006; Louws et al., 2010; Rivard et al., 2010a; Venema et al., 2008). In the United States, vegetable grafting is gaining in importance because of the phase out of soil fumigation with methyl bromide (King et al., 2008). Since the price of methyl bromide is increasing and the price of grafted plants is decreasing, vegetable grafting may be an economically viable method of disease control in the United States.
The continued increase in demand for foods produced organically (Greene et al., 2009) may also have helped fuel the interest in vegetable grafting in the United States. For instance, organic growers have used grafting to control RKN (Kubota et al., 2008), which are a major problem in the sandy soils common to Florida (Roberts et al., 2005). RKN-resistant tomato rootstocks have been shown to reduce RKN galling and maintain yields (Bausher, 2009; Louws et al., 2010; Rivard et al., 2010b; Verdejo-Lucas and Sorribas, 2008). However, grafting in the United States has not yet reached its full potential as a control for soil-borne pathogens and nematodes.
It has been estimated that 40 million grafted vegetable transplants are currently used in the United States every year. Most of these plants are produced in Canada and are used by major greenhouse tomato producers for season extension and increased crop vigor (Kubota et al., 2008). In contrast, over 200 million grafted tomato transplants are used annually in Japan and Korea for improved crop production and relief from soil-borne pathogens, temperature extremes, and soil salinity (Lee et al., 2010). Grafting in the United States is expected to expand greatly in the coming years as more uses are realized, high-quality transplants become more available, and prices for grafted transplants are reduced (King et al., 2008; Kubota, 2008; Lee et al., 2010).
High labor costs and low return per plant have been suggested as barriers to adoption of grafted vegetable production in the United States. (Rivard et al., 2010b). Lee et al. (2010) reported prices of grafted transplants between $0.40 and $1.20 for various crops. Grafted tomato transplants can cost between $0.60 and $0.90 per plant without factoring in seed costs (Kubota et al., 2008). Although interest in this technique is on the rise, there has been little reported on the price of grafted transplants for vegetable production in the United States. Prices for domestic grafted tomato plants were estimated by Rivard et al. (2010b) at $0.59 (on-farm, organic) and $1.88 (retail, double-stem pruned for greenhouse production) as compared with $0.13 (on-farm, organic) and $0.76 (retail, double-stem pruned for greenhouse production) for nongrafted plants in two different transplant production facilities. However, to our knowledge, there have been few studies examining both the cost of grafted tomato transplants and their expected return. This information could help growers decide if the extra cost of grafted transplants could be justified by increased output or by the reduction of production inputs when using grafting to overcome soil-borne diseases.
Florida growers and transplant producers interested in vegetable grafting need information based on local production systems. The purpose of this study was to determine the cost of producing grafted heirloom tomato transplants on-farm and estimate the economic return with expected yields for organic growers interested in implementing this technique. Sensitivity analyses were performed to assess the economic feasibility of growing grafted heirloom tomato plants. These analyses were developed using fruit yield information from field trials of heirloom tomato grown under different levels of RKN infestations.
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