Q.Mandarin orange tree
My dad has a mandarin orange tree and the fruit is sour tasting. How can we get them to produce sweet fruit instead of sour fruit?
There are many factors that go into growing good citrus fruit, including temperature, watering, fertilizing, pruning, correct harvesting and the variety that you are growing.
Optimizing the growth of the tree will help in the final product, but keep in might that some varieties are actually a sour fruit. These citrus are used for jelly and jams.
Another issue is root stock take over. Root stock of citrus is generally a less flavorful citrus variety.
Here are some articles with more information.