Water status response of pineapple using destructive and non-destructive indicators and their relations in two contrasting seasons

The use of indicators to assess the water status of pineapple grown inside greenhouses is essential to obtain higher yields. Although destructive and non-destructive indices are widely applied to monitor several crops, there are no previous reports that evaluate their response to different seasons or the relationship between the indicators and the water status of pineapple plants. The experiment was conducted during the warm and cold seasons, comparing two treatments: plants irrigated to field capacity (FC) and non-irrigated (NI). The water status was measured using a destructive index, Relative Water Content (RWC), and non-destructive indices, Normalized Difference Vegetation Index (NDVI), and Stress Degree Day (SDD). The environmental conditions monitored were temperature, humidity, and photosynthetically active radiation (PAR). At the end of each season, plant biomass and assimilate partitioning (AP) were also determined. The recovery of the NI treatment by irrigation was measured using NDVI and RWC. In the cold season, differences between treatments were detected after 45 days of water restriction by NDVI, while in the warm season, the RWC index found differences a week after the experience began (p < 0.05). SDD was the most sensitive index since it increased in both seasons and presented significant differences in the early stages of the experiment between treatments in the early stages of the experiment. RWC had intermediate correlations with non-destructive indicators, NDVI and SDD, in both seasons (p < 0.05). The AP and its correlation with the water status indices varied between seasons due to different environmental conditions. The RWC and NDVI response to the re-hydration of the substrate in the NI was immediate; however, NDVI values were lower than at the beginning of the experiment. This work highlights the viability of both destructive and non-destructive indicators for the determination of pineapple water status and its relationship with AP in two contrasting seasons.