And, some trees may be more resistant to diseases. Naturally, citrus growers, to ensure the best possible crop, want to make sure all their trees are of the same high quality. To do this, each new tree they plant is grown, or propagated, not from a seed but by grafting or budding. In most citrus trees, the scion, or top of the tree, is a different variety from the roots or rootstock of the tree. Citrus growers plant trees whose tops will grow 'Washington' Navel oranges or 'Eureka' lemons on a rootstock that has special characteristics like disease resistance, quick to bear fruit or restricting tree size for easier harvesting.
Nurserymen begin the process of propagating a new citrus tree by planting a seed for the rootstock.
While many rootstocks are produced by seed, because of nucellar embryony, they are all the same. After the rootstock is a year old, a single bud is taken from a branch of the desired scion variety and inserted into the bark of the young seedling. This bud grows into the top of the tree that produces the fruit. Fruit Development Citrus flower buds begin to form in early winter and develop through late winter and spring. Because the number that do become fruit depends largely on temperature and moisture, adequate water is very important during and immediately after flowering.