Aplicação do composto orgânico humificado associado ao paclobutrazol no florescimento e produção da mangueira ‘Palmer’

Abstract

The northern region of Minas Gerais stands out in the production of mango by the use of paclobutrazol (PBZ), a plant growth regulator that, together with other management practices, provides the most uniform flowering at any time of the year. However, its efficiency is very unstable, due to the little mobility of the molecule in the soil. Humic substances have shown promise in enhancing the absorption of ions and molecules, since there are indications in the literature that humic and fulvic acids have effects on the absorption of ions, which may contribute to the absorption of PBZ by the root system. In this sense, the objective of this study was to evaluate the application of doses of the humid organic compound associated with the doses of PBZ in the flowering, production and fruit quality of the 'Palmer' mango tree in two seasons. Two experiments were carried out at different times and areas of production, both located in the municipality of Matias Cardoso, MG. The first experiment, carried out between the months of July 2018 and April 2019, had its implantation in the dry season and its conclusion with harvest in the rainy season, while the second experiment, carried out between the months of October 2018 and July 2019 , had its implantation in the rainy season and its conclusion with harvest in the dry season. The experimental design adopted was in randomized blocks, with four replications, in a 4x2 + 1 factorial scheme, corresponding to doses of humidified organic compound (10; 15; 20; 25 mL per plant) and doses of paclobutrazol (0.7 and 0 , 85g of active ingredient / m of crown diameter), plus a control (paclobutazole only: 0.85 g of active ingredient / m of crown diameter). Vegetative, physiological, reproductive, productive characteristics as well as the quality of the fruits were evaluated, by which they were subjected to analysis of variance and regression or average tests. In the first production season, there was a significant effect on the relative chlorophyll content (SPAD index), total number of flowers, male flowers number, soluble solids content and titratable acidity. The other characteristics of the first season were not influenced. The treatments did not influence any of the characteristics in the second season of production. When the effect of treatments (organic compound associated with PBZ) was compared with the control, there was higher chlorophyll 2Guidance committee content for the treatments, indicating possible influence of organic compost on the leaf assimilation surface. The increase in doses of organic compost linearly increased the total number of flowers (452) and the number of male flowers (373) per axillary panicle at the maximum dose of 25mL / plant. However, at the same dose, the soluble solids content was reduced to 12.72 ° Brix. The use of the lowest dose of PBZ (0.70 g a.i./m) was sufficient to promote a higher content of soluble solids and titratable acidity in the fruits. The average productivity of the first and second seasons was higher than the regional and Brazilian average. However, the first season was more favorable to obtain the results, suggesting possible influence of temperature and precipitation. For economical issues in the production system and the most important characteristics not having been influenced by the treatments, the use of the humid organic compound associated with the paclobutrazol in the management of floral induction of 'Palmer' mango tree, justifying the use of paclobutrazol alone.