Girdling alters carbohydrate allocation to increase fruit size and advance harvest in tomato production

Abstract This study aimed to examine the effects of girdling on tomato (Solanum lycopersicum L.) plant growth and fruit development, and identify appropriate girdling time on tomato. Girdling was carried out on tomato main stems at four different girdling time: 0 days after anthesis of the last truss (0 DAA), 7 DAA, 14 DAA, and 21 DAA, respectively. Tomato plants that were not treated with girdling served as the control. Girdling altered carbohydrate allocation to different organs. With more carbohydrates partitioned to fruits, girdling significantly increased the fruit weight and yield, and advanced the commercial harvest time by approximately 10 days in comparison to the control. Due to a lack of carbohydrate supply, root biomass and carbohydrate concentration reduced in the girdled plants. No evident sink feedback inhibition of photosynthesis was observed in leaves after girdling. Considering plant growth and fruit development, the appropriate girdling time was approximately 2–3 weeks after anthesis of the last truss. Our results have demonstrated that the application of girdling on tomato plants can increase fruit size and accelerate fruit development, which provides an effective approach to regulate carbohydrate partitioning in tomato production.