2019 ASHS Annual Conference

Pineapple (Ananas comosus (L.) Merr.) is a popular tropical fruit in Taiwan where the climate includes tropical and subtropical zones. Adjusting cultivation practices make it possible to grow high quality pineapples year-round in Taiwan. Covering protection, a practice of shadowing fruits from climate changes, is an ideal method to avoid sunburn and cold damage, as micro-environmental conditions highly affect fruit appearance and quality. In this study, we examined three treatments for fruit protection by using polyethylene film to cover the entire plant, on top of the bush for the fruit itself, or with secondary protection of paper bag on fruit under the film. In the winter, fruits were mature the earliest when entire plants were covered with film. When only the fruits were covered with the film, inter fruitlet cracking numbers were 9.3±3.6, and total soluble solids were 13.6±0.4°Brix. However, covering the entire plant with film to the ground led to higher inter fruitlet cracking numbers 20.3±5.9 and pineapples exhibited sunburn injury as the resulting temperature of fruit shoulder was 20°C higher than the environmental temperature. In early spring, total soluble solids reached 15.4±0.7°Brix, and titratable acidity was 0.52% for fruits covered with both film and paper bag, as the paper bag provided secondary protection. Spring fruits were the heaviest and had the best appearance with secondary protection, and also this treatment enhanced fruit quality with higher total soluble solids. Proper air circulation under the film ideally provides thermal insulation and also keeps sunburn degree low. In sum, our study highlights the importance of understanding micro-environmental conditions for growing pineapple.