Produção de mudas de cultivares de maracujazeiro (Passiflora spp.) em função de fontes e doses de silício

Abstract

The passion fruit tree is a climbing fruit tree that is widely cultivated in all regions of Brazil and has undergone updates in the production system for single-cycle crops, making it feasible to use tall seedlings. Two experiments were carried out with the aim of evaluating the development of passion fruit seedlings submitted to the application of sources and doses of silicon around the stem (drench) directly into the substrate. The design used was randomized blocks (RBC). In the first experiment, in a 5x4 factorial scheme, five cultivars were evaluated in the absence of silicon, magnesium silicate, potassium silicate and silicic acid at the equivalent dose of 0.084 g L-1 of silicon per application, distributed in three blocks. In the second experiment, a 5x4 factorial scheme was used to evaluate four passion fruit cultivars in combination with silicic acid concentrations (0 g L-1, 0.1 g L-1, 0.2 g L-1, 0.4 g L-1 and 0.8 g L-1), distributed in three blocks. The cultivars were BRS Gigante Amarelo, BRS Sol do Cerrado and BRS Rubi do Cerrado, BRS Mel do Cerrado and BRS Pérola do Cerrado. The seedlings were grown in a greenhouse at the State University of Western Paraná, Marechal Cândido Rondon Campus. Two evaluations were carried out, at 77 days after sowing (DAS) and 157 DAS, of plant height, collar diameter, number of leaves and SPAD index and, for the second, in addition to these, number of internodes, aerial, root and total dry mass and Dickson quality index. When comparing the silicon sources, no difference was found for plant height, collar diameter and SPAD index at 77 DAS. At 157 DAS, the application of potassium silicate increased the SPAD index and the treatment with silicic acid increased the dry mass of the stems and roots. Except for the number of leaves at 77 DAS, the cultivars responded differently to the absence and levels of doses applied. Regardless of the doses and the interaction between treatments, cultivar BRS Mel do Cerrado had the lowest averages for height and SPAD index at 77 and 157 DAS. The cultivar BRS Sol do Cerrado at the estimated dose of 0.18 g L-1 was the most suitable for producing a quality seedling according to the Dickson Quality Index (IQD) and BRS Gigante Amarelo had the highest plant height regardless of the dose level tested.