Marc Chillet

Pre-harvest growth and development, measured as accumulated degree days, determine the post-harvest green life of banana fruit

Summary We aimed to define a more robust indicator for banana harvest date that ensures an optimal fruit green life (GL). Our hypothesis was that development rather than growth would account for GL more accurately. To this end, five indicators were compared: one related to fruit size (i.e., growth, expressed as the diameter of fruit); two related to fruit age [i.e., development, expressed as the age of fruit measured in the number of days or in degree days (°Cd) from inflorescence emergence]; and two related to metabolism during maturation (i.e., the concentrations of malate and citrate in the pulp). Different treatments (e.g., fruit removal, leaf shading, bunch bagging, defoliation, water deficit, and flooding) were applied to modify the fruit growth rate. On different dates between the emergence of the inflorescence and harvest, fruit GL and the five indicators were measured. The results showed that there was a decreasing exponential relationship between GL and accumulated °Cd from inflorescence emergence (r2 = 0.77). This was more reliable than the relationships between GL and fruit diameter (r2 = 0.39), or between GL and fruit age, expressed in days (r2 = 0.39). Relationships were also established between GL and malate or citrate concentrations, but they were not sufficiently reliable to estimate GL. The results illustrate that GL is related to fruit development, and that °Cd is a more reliable criterion for harvest date than the number of days, or fruit diameter, because it is less sensitive to different fruit growth rates. Banana growers in the French West Indies usually use fruit diameter and age in days to determine harvest date. However, they face problems of fruit ripening during transportation. The use of °Cd as an indicator may help to determine the optimum harvest date more accurately.

Crown Rot of Bananas: Preharvest Factors Involved in Postharvest Disease Development and Integrated Control Methods

Crown rot is a complex disease that affects export bananas in all banana-producing countries. Usually invisible when the fruits are packed for transportation from tropical countries to distant destinations, disease symptoms occur during shipment, ripening, and storage. This disease, characterized by rot and necrosis, affects tissues joining the fingers with each other, called the crown. It may reach the pedicel and even the banana pulp when crown rot is severe. Losses from 10 to 86% have been recorded for treated and untreated bananas, respectively. In this paper, we summarize the current knowledge on crown rot disease and associated control measures that must be considered throughout the production channel in order to be effective. We suggest a new approach to this postharvest disease of bananas: that of considering fruit quality potential in the field. This new concept of preharvest quality potential is a key factor to understanding crown rot development. Fruit quality potential depends on both a physio...

Black Leaf Streak Disease Affects Starch Metabolism in Banana Fruit

Black leaf streak disease (BLSD), also known as black sigatoka, represents the main foliar disease in Brazilian banana plantations. In addition to photosynthetic leaf area losses and yield losses, this disease causes an alteration in the pre- and postharvest behavior of the fruit. The aim of this work was to investigate the starch metabolism of fruits during fruit ripening from plants infected with BLSD by evaluating carbohydrate content (i.e., starch, soluble sugars, oligosaccharides, amylose), phenolic compound content, phytohormones, enzymatic activities (i.e., starch phosphorylases, α- and β-amylase), and starch granules. The results indicated that the starch metabolism in banana fruit ripening is affected by BLSD infection. Fruit from infested plots contained unusual amounts of soluble sugars in the green stage and smaller starch granules and showed a different pattern of superficial degradation. Enzymatic activities linked to starch degradation were also altered by the disease. Moreover, the levels of indole-acetic acid and phenolic compounds indicated an advanced fruit physiological age for fruits from infested plots.