The first oranges
Where did the citrus originate? Botanist Chozaburo Tanaka was an early proponent of the Indian origin of the citrus. An exhaustive study of the genomes of many citrus varieties concluded that the last common ancestor of all the varieties we see today grew about eight million years ago in what is now Northeast India (overlapping Meghalaya, Assam, Arunachal, Nagaland and Manipur) and adjacent regions of Myanmar and Southwest China (Wu, et al, Nature (2018) 554, 311-316) This region is, famously, one of the world’s richest biodiversity hotspots. A biodiversity hotspot is defined as a region that contains at least 1,500 species of native plants, and has lost at least 70% of its vegetation. The Northeast corner has 25% of India’s forests and a large chunk of its biodiversity. Here you will find tribes such as the Khasi and Garo, and nearly 200 spoken languages. This area is also a rich repository of citrus genomes, with 68 varieties of wild and developed citrus found here today.