Exploring the Potential for Grafted Tomatoes to Increase Yields, While Decreasing Soil Fumigant Use, in California.

In 2013 California growers used 5.7 million lbs of soil fumigants in the production of 12 million tons of tomatoes with a total value of $1.2 billion.  One method for reducing the use of fumigants and other agrochemical inputs in tomatoes, while improving yields, is to use plants which consist of a scion of a high-yielding variety grafted onto a multi-soil-borne pathogen resistant rootstock.  Field trials throughout the United States and abroad have consistently shown multiple economic and environmental benefits of using grafted fresh market tomato plants, including higher yields; reduced water, fertilizer and pesticide inputs; and enhanced tolerance to pathogens, saline soil, heat or cold. Yield and economic performance vary with the selected varieties and growing conditions. Grafted tomatoes have not been field tested in conventional commercial production in California, and existing commercial rootstocks have mostly been tested with fresh market varieties. Drawing on the extensive field trial results obtained elsewhere with grafted fresh market tomatoes, and considering California’s unique commercial fresh market tomato varieties, we are performing field trials in Merced County and San Joaquin County using several scion/rootstock combinations.  The results of these trials will be presented along with an extensive review of yield and economic data from the literature.  In 2016 we will conduct a second set of field trials which may include testing the yields obtained with grafted plants with pathogen-resistant rootstocks in a pathogen-infested experimental field.

This project is funded by USDA Specialty Crop Block Grant #SCB14027