Fisiologia da produção de tomateiro enxertado em cultivo sem solo

Abstract

Grafting on vegetables has grown considerably and has been a management alternative for overcoming adverse soil cultivation conditions, going beyond just conferring resistance to soil pathogens, as it is also used to overcome abiotic stresses. In this sense, grafting can be an ally on soilless grown, because, according to the experiences of producers, the technique, in addition to ensuring greater vigor, can give the grafted plants greater capacity for absorbing water and mineral nutrients, and increase the longevity of the plants. Consequently, grafted plants can be carried out with two stems maintaining the same or better productive results than single-grafted non-grafted plants per unit area. This thesis seeks to answer some questions about the behavior of grafted tomato plants in soilless grown systems, since the studies are practically non-existent, with insufficient scientific evidence to prove their productive superiority. In addition, no studies were found to assess physiological aspects of grafted plants compared to non-grafted plants. Thus, this work aims to assess the effect of grafting and the number of stems on growth, physiological aspects, and absorption of mineral nutrients from tomato plants, as well as to evaluate fruit productivity and quality in soilless grown systems under appropriate conditions of temperature and light and under restriction. The experiments were carried out in a cultivation system in substrate of raw rice husk, carbonized and aeroponics. The variables analyzed were as to plant growth (number of leaves, leaf area index, stem length, shoot dry matter, root dry matter and total dry matter), as to physiological aspects (photosynthetic rate, stomatal conductance, transpiration, intercellular CO2 concentration, and nutrient absorption), and production (number, mean weight of fruits, production, productivity, concentration of soluble solids and fruit dimensions). In general, grafted plants show greater vegetative and root growth than non-grafted plants, regardless of the cultivar employed and the crop. The grafting can present positive, indifferent and negative productive results due to the cultivars used and the interaction between graft and rootstock, the management used, the time of year, and the duration of the cultivation cycles, in most of the experiments, the grafted plants showed higher production and mean weight of fruits compared to the non-grafted plants. Fruit quality, expressed in ºBrix, was not affected by grafting. Plants driven on a single stem are more productive. The grafting factor did not affect the physiological variables. While the single-stem conduction showed greater stomatal conductance than those conducted with two stems. As well as these plants they also present greater vegetative growth and fruit production, in addition to absorbing more nutrients than the plants carried out with two stems that only stand out for presenting a more developed root system.