Lemon rootstocks produce big quantities of fruit, but the fruit's quality is always poor. Lemon as a rootstock is normally used only for commercial juice production where they want to emphasize quantity. They then mix with smaller amounts of other juices to get the right taste. An advantage of the lemon stock is rapid growth, it being more vigorous than other rootstocks. However, this also results in poor taste. Traditionally lime rootstocks produce trees with a higher yield of fruit, but then as the tree ages the yield falls off. There are many rootstocks much better for mandarin then either lemon or lime. Currently I am growing both lemon and lime on Flying Dragon rootstock. - Millet