Eficacia de aviglicina en la reducción de la floración natural en piña en Costa Rica

Abstract

The naturally differentiated flowering (NDF for its acronym in English) in Ananas comosus is regulated by low temperature and short days, stimulating greater ethylene biosynthesis. The efficacy of aviglycine (AVG) as an inhibitor of ethylene biosynthesis during the period of highest susceptibility of ‘MD-2’ pineapple plants in the Huetar Norte region of Costa Rica was evaluated. Three doses of the PinCor® 20 SL formulation were studied in high volume (2,000 L ha(-1)) and low volume (25 L ha-1) in plants from 213 to 225 days of age and from 1.7 to 1.87 kg of fresh weight, through applications with a seven-day interval between weeks 48 of 2015 and eight of 2016. PinCor® 20 SL (AVG) (0.25, 0.50 and 1.0 L ha(-1)) at 25 L ha(‑1) (2,000, 4,000 and 8,000 ppm) and at 2,000 L ha(-1) (25, 50 and 100 ppm) reduced natural flowering from 43.7 to 6.9% without affecting sensitivity to exogenous ethylene applied foliar, although the magnitude of the phenomenon could be influenced by the microenvironment. The volume applied did not affect the efficacy, while as the dose was increased the incidence was significantly lower and at 8,000 ppm it suppressed the natural flowering at 100%, although at high concentrations it generated symptoms of mild temporary chlorotic reaction in the plants. 100% natural flowering was expressed between weeks two and eight of 2016, coinciding with the exposure of the plantation for more than 50 min a day to a temperature lower than 20°C associated with a day-night temperature amplitude lower than 4°C; the incidence of NFD tending to increase as the period of foliar exposure increased.