History and development of the citrus industry. Plant characteristics and climatology. The commercial citrus regions of the world; theri physiographic, climatic, and economic characters. The botany of citrus and its wild relatives of the orange subfamily. Cultivated varieties of citrus. Cultivated varieties of citrus. General morphology, histology, and physiology. The mineral nutrition of citrus. Seed reproduction: development of gametees and embryos. Seed Reproduction. Genetics and breeding. Bud variation and bud selection.