Small-statured tomato plants for automating greenhouse production: opportunities, constraints, and research priorities

Systems based on small-statured plants could contribute to the future of automated tomato production, but require an integrated approach of cultivation, crop management, plant physiology, breeding, robotics, and modelling. Greenhouse tomatoes are typically grown according to a high-wire system, where plant stems reach 10 m or more in length during one cycle of production. This system has served the industry for about 50 years, and allows for near-continuous year-round production, high yield, and good fruit quality. However, it is labor intensive, requiring manual fruit harvest, pruning of side shoots and leaves, as well as training the stem around the support string. The viability of high-wire cultivation is now challenged by high labor costs and shortage of workers. In this perspective paper, we propose two alternative tomato production systems: dwarf tomato and limited-truss tomato (LTT). They both produce small-statured tomato plants with short cultivation cycles, which may improve compatibility with automated production. We evaluate and compare the two production systems based on yield, light use efficiency, fruit quality, and labor requirement. Future directions for both research and industry for innovative tomato production are presented as well.