Answer: Splitting is the result of environmental or cultural conditions. It happens when water and sugar are transported from the roots of the plant to the fruit and the rind is not able to expand quickly enough to contain the added pressure. This is more common on thin-skinned oranges or fruit that is sunburned and therefore less elastic.
Splitting is usually associated with fluctuations in temperature, humidity and soil moisture. You can help avoid the problem by watering and fertilizing regularly while the fruit is developing. While the split fruit is edible, it is usually immature and not very tasty. Rusty colored spots on the fruit are typically a result of wind damage and scarring and will not affect the quality of the fruit.
Best wishes with your orange tree.
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