Influencia de la poda y la aplicación de nitrato potásico y tiosulfato potásico sobre las características florales del mango (Mangifera indica L.) cultivares Irwin y Tommy Atkins en la planicie de Maracaibo, Venezuela

Abstract

The Maracaibo plain has acceptable agroecological conditions for mango production. In this study, the influence of pruning and both potassium nitrate and potassium tiosulphate applications were evaluated on flowering characteristics of the cultivars Irwin and Tommy Atkins, which are produced in this region. The research was conducted on the Maracaibo plain, at the Centro Frutícola (CENFRUZU), Mara County, Zulia State, Venezuela. A factorial design was used, with two treatments of pruning at two levels (with and without pruning), two flowering inductor levels (potassium nitrate KNO3 6% and potassium tiosulphate TSK 1%), plus a control treatment, without neither pruning nor promotors. The treatments were located at random using two cultivars: Irwin and Tommy Atkins with four plants per treatment. The experiment was repeated during two productive cycles (2003-2004 and 2004-2005). For each cycle, two different experiments were carried out considering the treatment application date: early and late induction, for a total of four experiments. Panicle length and width, panicle number per plant, number of hermaphrodite and masculine flowers, and hermaphrodite and masculine flowers ratio were evaluated. On the Irwin cultivar, the panicles number increased from 550% to 600% with the application of potassium nitrate, during early induction and 200% during the late one. On the Tommy Atkins cultivar, the effect of potassium nitrate on panicles number was lower. The hermaphrodite-masculine flowers ratio increased with the potassium nitrate application on the Irwin cultivar during early induction. Panicle size decreased when potassium tiosulphate was applied in combination with pruning in both cultivars and induction dates. These results showed that potassium nitrate combined with pruning on the Irwin cultivar produced the best effect on floral characteristics, when compared to the control.