Preharvest foliar applications of glycine-betaine protects banana fruits from chilling injury during the postharvest stage

Banana plantations are affected by environmental factors such as chilling injury, which reduces the quality of fruits and causes losses of up to 50% in the yield of banana and it will be more important in terms of global climate change. Chilling injury of the fruits can also occur during transport and storage at low temperatures, particularly in tropical fruits. In banana, losses of up to 20% can occur during postharvest handling. Given this situation, it is necessary to explore alternatives that might reduce chilling injury, such as the use of compatible solutes including glycine-betaine (GB). In the present work, experiments were performed to analyze the possible role of preharvest foliar applications of GB, to prevent the subsequent development of chilling injury of banana fruits during the postharvest storage at low temperatures. After 3 days of the preharvest application of 100 mM GB over banana leaves (250 ml/plant), the fruits were harvested and first stored at 10°C for 6 h and then transferred to 23°C ± 1°C until they reached commercial ripening. A second group of plants were not treated with GB during the preharvest stage, but their fruits were exposed to 10°C for 6 h before transferring them to 23°C ± 1°C until they reached commercial ripening. A control group was untreated with GB during the preharvest stage, and fruits were not exposed to low temperatures but they were kept at 23°C until they reached commercial ripening. The results showed that the preharvest foliar application of GB (100 mM) to banana plants reduced the biochemical and physiological alterations caused by chilling injury on harvested fruits.