## 3 Discussion  
Different varieties and cultivars of banana fruits may be different in their storage capacity and flavors due to the differences in their physiological characteristics (weight, size, shape, texture and color), physicochemical properties (pH, titratable acidity, soluble solids, moisture content, and total solids), chemical properties (soluble sugars, vitamin C, starch, pectic substances, and volatile compounds) and sensory attributes (appearance, flavor, odor, color, firmness) [16; 19]. For example, the genome of B group (B-_Musa ballisiana_) cultivars showed a greater resistance to low-temperature stress compared to the AAA group (A-_Musa acuminata_) [20]. Different banana cultivars produce different volatile compounds in response to cold storage, enhancing their ability to tolerate low temperatures [21]. It has also been reported that growth altitude affects the composition of volatile compounds [7]. Two cultivars of banana, Brazilian and Fenjiao, were selected for this study. Our results showed that Fenjiao fruit ripened much more rapidly than the Brazilian fruit (Figure 1). Fenjiao fruit turned yellow more rapidly than Brazilian fruit, and fruit firmness decreased rapidly for Fenjiao. The respiration rate and ethylene production were much greater in Fenjiao banana fruit compared to the Brazilian fruit (Figure 1D,E). These results indicate that the storage capacity of Fenjiao banana fruit is much shorter than Brazilian fruit, which may mainly be due to the high respiration rate, highly commercial harvested maturation, genotype, peel structure, etc. Respiration is an excellent indicator of metabolic rate of fruit, and it can also work as a useful criteria for the storability of fresh produce [22]. Normally, horticulture produce with a low respiration rate (such as apple, potato, carrot, etc.) show long-term storability while high respiring produce (such as strawberry, papaya, banana and litchi) have a short storage life. Fenjiao fruit showed high respiration rate than Brazilian, which well explained that Fenjiao fruit showed short storage life. Ethylene is well known as a ripening hormone, which can trigger ripening in climacter fruits and senescence in non-climacteric fruits, vegetables and ornamental plants [23]. High ethylene production also accelerate fruit ripening. Fenjiao fruit also showed high ethylene production than Brazilian and with a short storage time. Manipulating ethylene production is an effective way to either promote rapid and predictable ripening of climacter fruits or to delay ripening. The postharvest technologies of controlling fruit respiration and ethylene have been extensively studied [24]. As an ethylene receptor inhibitor and a nontoxic antagonist of ethylene, 1-methylcyclopropene (1-MCP) has been employed to increase the shelf life of various climacteric and non-climacteric fruits, which can effectively prolong the shelf-life of both Fenjiao and Brazilian banana fruit. Our previous work showed that the combination of 1-MCP and ethylene could effectively delay banana fruit ripening [24]. Glucose, fructose and sucrose are three main sugars in banana fruit during fruit ripening [25]. Actually, the abundance of all three sugars was significantly higher in Fenjiao fruit than in Brazilian fruit (Table 1). The contents of the three sugars in the fruit of the banana increased with fruit ripening and reached a maximum at full ripening. Our results show that the most abundant sugars in Fenjiao banana are glucose and fructose, which is different from most fruits, such as litchi, pineapple, and other banana cultivars, in which sucrose is the predominant sugar at full ripening [26]. In the Brazilian banana fruit,when the fruit reached full maturity, the contents of three kinds of sugar were similar to one another, and the Brazilian contained higher concentrations of sucrose but lower concentrations of glucose and fructose than Fenjiao fruit.