Influência do sombreamento associado ao uso de regulador de crescimento em características agronômicas do girassol ornamental (Helianthus annuus)

Abstract

One of the bottlenecks seen by ornamental sunflower producers in the semi-arid region of the Northeast are edaphoclimatic factors, such as temperature and excessive light, in addition to practical crops, such as soil cover, making it necessary to carry out alternatives that mitigate this stress caused on the plant. Thus, an experiment was conducted in an experimental area at the Federal Rural University of Pernambuco, at the Serra Talhada UFRPE / UAST Academic Unit, from November 2019 to January 2020. With this work, the effects of using of different levels of shading combined with regulator of different dose levels in the growth, development and production of flowers in the sunflower culture. The experimental design used was completely randomized in a 4x4 factorial scheme, with treatments referring to the four levels of growth regulator doses 0; 2; 4 and 6 mg / L-1 in interaction with four shading 0, 30, 50 and 70% for flower production in sunflower culture. Three repetitions were used, with two replicates for each repetition, where the sunflower was evaluated. The treatments started to be applied 15 days after seedling emergence (DAE) and another 15 days when the plant had 6 true leaves. Due to flowering, the phytomass, fresh and dry plant variables, number of leaves, buds and flowers, and plant height were evaluated. In relation to plant height for commercialization, the control showed a better performance. Shading at 30% showed increases in fresh and dry phytomass. For the number of leaves, the highlight was the 70% shaded plants.