Grafted Vegetable Plants

The interest in grafted vegetable plants stems from their having often been shown to be superior in some way to ungrafted ones. Heightened performance under various types of stress — e.g., disease, nutrient, water, salt — is regarded as the fundamental benefit of using grafted plants.
Any advantage that a grafted plant may provide begins with its rootstock-scion combination. Likewise, when incompatible, the rootstock-scion combination also works to limit the performance of the grafted plant. Therefore, the successful integration of grafted plants into vegetable production systems hinges on the extent to which rootstock-scion interactions are understood and can be manipulated.
Two papers written by teams operating in Spain where grafted vegetable plant use is common offer valuable perspectives on this subject. Martinez-Ballesta and coworkers summarize physiological and biochemical aspects of rootstock-scion interactions, shedding light on how they may affect multiple aspects of grafted plant behavior and status. San Bautista and cowoworkers report on the rare but potentially valuable technique of double-grafting involving three plants. In this type of double-grafting, an intermediate rootstock is used to increase the compatibility of the scion and primary rootstock, which may lead to dramatic improvements in scion growth, nutrient uptake and water use efficiency.