Densidades de plantio e ciclos de cultivo na produção e qualidade de frutos e fenologia reprodutiva da pitaia vermelha

Abstract

Pitahaya (Cactaceae) has emerged in the Brazilian market as a new and promise exotic fruit crop. Therefore, there is a lack of information for the improvement of its cultivation system. Thus, this investigation aimed to evaluate the planting densities and crop production cycles in terms of the productivity, fruit quality and reproductive phenology of red pitahaya (Hylocereus sp.). The trial was carried out in an experimental area of the Federal University of Ceará, Ceará, Brazil. Two experiments were performed. One with planting density and production cycles, in a randomized blocks and subdivided plots, with three planting densities in the plots (1 plant/pit; 2 plants/pit; 4 plants/pit) and the cycle (cycle 1 and cycle 2) in the subplots, with six replicates. Each experimental unit consisted of two pits, with 84 plants distributed in 36 pits. The productivity and fruit quality parameters were evaluated. In the second experiment, the reproductive phenology was evaluated, in the dry and humid seasons of each one of the two production cycles. In the 84 plants of experiment 1, the quantification of flower buds, flowers, and fruits were carried out, and to determine the number of days of phenophases, a sample of 20 plants was randomly selected. The results of experiment 1 are followed: 4 plants/pit increased fruit yield and reduced the average mass of fruit, with no difference in the number of fruits per plant between treatments. The morphometric variables were not influenced by planting density. In the second production cycle, there was an increase in fruit quality for the physical, physical-chemical, bioactive compounds and antioxidant activity variables. The results of experiment 2 are followed: from the emergence of a flower bud to ripe fruit were taken 43 to 56 days; the indexes of flower bud /flower and fruit/flower were higher in the humid season and the highest flowering and fruiting peaks occurred from January to April (cycles 1 and 2). The red pitahaya showed 11 (1st cycle) and 9 (2nd cycle) production peaks. The production of flower buds, flowers, and fruits showed a positive correlation with temperature; the production of fruits showed a positive correlation with relative humidity and precipitation. The insolation had a negative correlation with the fruit production.