Effect of grafting and number of stems on plant growth, yield and fruit quality of soilless tomatoes

Abstract

Vegetable grafting has grown considerably and has been a management alternative to overcome adverse soil cultivation conditions. However, many growers have used grafted tomato plants in substrate cultivation, claiming greater plant vigor, fruit yield, and longevity. Thus, the work objective is to evaluate the effect of grafting and the number of stems on plant growth, fruit yield, and quality of the Italian tomato, cultivated in a system of troughs filled with raw rice husk substrate. The experiments were conducted in southern Brazil, in the 2017/18 (long cycle) and 2019/20 (short cycle) crop seasons. The cleft grafting was used. The analyzed variables were the number of leaves, leaf area index, vegetative and fruit dry matter production, plant total dry matter, number of fruits, fruit yield, mean fruit weight, and total soluble solids content (ºBrix). The grafted plants had higher LAI, fruit dry matter production, fruit number, and yield (17 and 19%, respectively, in the first and second crop seasons). The quality of the fruits, concerning the concentration of sugars, was not affected by grafting, and the mean fruit size was increased by 7.9 and 8.1 grams (long and short cycle, respectively). In a long cycle, both for grafted and non-grafted plants, single-stem plant cultivation promotes 13.54% more plant growth and is 4.86% more fruit yield than double-stem plants. In a short cycle, from the point of view of reproductive growth and fruit yield, for both types of plants, cultivation with two stems is like that of single-stem plants.