Crescimento e produção da bananeira 'Prata Gorutuba' em plantio adensado

Abstract

The increase of plant density, different types of management in the crop and the use of beneficial microorganisms have been adopted as alternatives to increase the productivity and to produce in a sustainable way. The objective of this work was to evaluate the growth and production of the 'Prata Gorutuba' banana, in two productive cycles in the semiarid state of Minas Gerais, submitted to planting of seedlings inoculated with endophytic bacteria at different spacings. The acclimatization of the micropropagated seedlings was carried out in a greenhouse in two systems: tubes (60 days of acclimatization) and bags (120 days of acclimatization). To perform microbiolization banana seedlings were used five strains from the laboratory of Plant Pathology, University of Montes Claros - Unimontes. After multiplication of the bacteria in the laboratory, the five isolates were equally mixed, and 25 mL of the suspension was applied to the seedlings at twenty day intervals. Only half of the seedlings produced in the bag system received bacterial inoculation. The experimental design was a randomized block design, with four replications, nine treatments, each plot consisting of 20 plants, using the six central plants as a useful plot. It used tubule seedlings in treatment 1 and bags in the others and the planting density ranged from 1,680 to 3,920 ha-1 plants associated with different seed sizes and types of seedlings. The growth characteristics were evaluated only in the first productive cycle. However, the production evaluation, physical and chemical analyzes of fruits, productivity, gross and net income were performed for the first and second cycles. The data were submitted to analysis of variance and the means were compared to each other by the Scott-Knott test, at 5% probability. For the vegetative characteristics, the logistic growth curves were adjusted and the rates were obtained by the first derivative of the adjusted equation. Economic analyzes were performed regarding productivity, gross and net income in a descriptive way. The application of endophytic bacteria in the greenhouse, a process considered microbiolization, provided an increase in the size of the seedlings, however, when the seedlings were taken to the field, differences were not observed between plants that received microbiolization with the others that were not microbiolized. The densification influences the elongation of the cycle, from the planting to the emission of the bunch in the first production cycle. In the first production cycle, the treatment with higher density of plants (3,920 plants ha-1 ) provides higher productivity and gross income, followed by treatment with 1,680 plants ha-1 , using endophytic bacteria and 50% nitrogen reduction, in relation to gross income. The densified treatments with more than 3,000 ha-1 plants present higher yields and gross income in the second productive cycle. The management of the crop showed a significant effect on the increase of the cycle for the treatments with total sowing until 10 months of age and total sowing until harvest. The water restriction of 42% and 43%, for the first and second cycle, respectively, negatively influences the vegetative and productive characteristics of the banana 'Prata Gorutuba' in the semiarid region of Minas Gerais.