Efecto del índice de estrés hídrico sobre el estado vegetativo de la planta de cacao

Abstract

The preliminary aim of this study was to evaluate the water stress index as an indicator of the absorption of water by the plant and its effect on the vegetative growth of the cocoa crop. An experiment was carried out in two environments (semi controlled and open field), during the years 2020 and 2021, in Almirante district, Bocas del Toro (Panama). In the semi controlled environment, four treatments and five repetitions (20 seedlings) were evaluated in a completely randomized design. The treatments consisted of different irrigation regimes, where T1= Witness; T2 = 60% humidity; T3= field capacity; T4= permanent wilting point. In the open field, it was carried out in a cocoa plantation where 24 seedlings were monitored. In both environments, normalized difference vegetation index (NDVI), soil temperature and plant (leaves) temperatures were measured using three-month-old seedlings of the improved AS-CP 26-61 cacao genotype. The data in the first study was monitored until the T4 plants died. In the open field, it was evaluated over a period of nine months, coinciding with the months of greatest and least rainfall. It was found that with a leaf humidity interval of 20 to 62%, the crop will present an NDVI of 0.40 to 0.80, with values ​​close to 1 being mostly favorable. On the other hand, for the period studied, the crop showed water stress in the months of March and May. It is concluded that cocoa plant presented a good vegetal vigor according to the NDVI, although they were affected with an index of water stress due to temperature in two non-consecutive months, which could affect the different phenological phases, affecting the low production.