The Tomaco plant produces two distinct food crops on a single stem: tomatoes above the soil line and potatoes underground. This unique creation demonstrates how closely related these different food sources can be. The plant is neither a genetic hybrid nor a result of cross-pollination, but rather a physically engineered specimen.
Defining the Tomaco
The pairing of tomato and potato is possible because both plants belong to the Solanum genus within the nightshade family, Solanaceae. This shared ancestry means they possess highly compatible cellular structures and vascular systems. The Tomaco is essentially two separate species sharing a single root system and stem, but maintaining their individual identities. The upper portion yields tomatoes, the ripened fruit, which draws energy from the leaves’ photosynthesis. Beneath the soil, the lower portion functions to store starch in the form of tubers.
The Science of Grafting
The Tomaco is created through a horticultural technique known as grafting, which manually joins the stem of one plant to the root of another. To form the Tomaco, a tomato stem, called the scion, is attached to a potato root system, known as the rootstock. Successful grafting relies on the precise alignment of the vascular tissues, specifically the xylem and phloem, between the two plant segments.
Specialized methods, such as splice grafting, are used to ensure the cut surfaces of the scion and rootstock meet perfectly. The union requires the development of a callus, which is undifferentiated tissue that bridges the gap between the two plants. New conductive tissue forms across this bridge, allowing the potato roots to transport water and nutrients up to the tomato foliage and fruit. This vascular connection is complete within about ten days, enabling the two parts to function as one cohesive organism.
History and Practical Application
While the Tomaco concept has existed as a novelty for decades, modern versions are often marketed toward home gardeners. For commercial agriculture, grafting is more commonly used to confer resistance to soil-borne diseases or environmental stress onto a preferred fruiting variety.
The Tomaco is not used in large-scale commercial farming for several reasons. Grafting is a labor-intensive process that requires careful synchronization of seedling growth to ensure matching stem diameters. Furthermore, the two crops have different cultivation needs and optimal harvesting times; potatoes require the foliage to die back to signal maturity, while tomatoes need a long, vibrant growing season for maximum fruit production. Because of these differing requirements, the Tomaco remains primarily a niche item, valued for its novelty and efficiency in small garden spaces.