Decaffeination this trait could be bred into other coffee plants by crossing them with "C. charrieriana", or an equivalent effect could be achieved by knocking out the gene for caffeine synthase in normal coffee plants. Tea may also be decaffeinated, usually by using processes analogous to the direct method or the CO process, as described above. The process of oxidizing tea leaves to create black tea ("red" in Chinese tea culture) or oolong tea leaves from green leaves does not affect the amount of caffeine in the tea, though tea-plant subspecies (i.e., "Camellia sinensis sinensis" vs. "Camellia sinensis assamica") may differ
Tea var. "sinensis") may have originated in southern China possibly with hybridization of unknown wild tea relatives. However, since there are no known wild populations of this tea, the precise location of its origin is speculative. Given their genetic differences forming distinct clades, Chinese Assam type tea ("C. sinensis" var. "assamica") may have two different parentages – one being found in southern Yunnan (Xishuangbanna, Pu'er City) and the other in western Yunnan (Lincang, Baoshan). Many types of Southern Yunnan assam tea have been hybridized with the closely related species "Camellia taliensis." Unlike Southern Yunnan Assam tea, Western Yunnan Assam tea shares