Short answers, pulled from the story.
Scientists have tentatively located the origin of Raphanus sativus in Southeast Asia, as this is the only region where truly wild forms have been discovered. India, central China, and Central Asia appear to have been secondary centers where differing forms were developed.
Under average conditions, the radish crop matures in 3 or 4 weeks. In colder weather, 6 or 7 weeks may be required for full growth depending on soil temperatures.
A raw radish is 95% water and provides moderate amounts of vitamin C at 18% of Daily Value per serving. The sharp flavor comes from glucosinolates and the enzyme myrosinase combining when chewed to form allyl isothiocyanates.
Citizens of Oaxaca celebrate the Night of the Radishes on December 23 during Christmas festivities. Daikon varieties make up the Japanese Festival of Seven Herbs on the seventh day after new year.
A German botanist reported radishes of 15 inches and roughly 20 inches in length in 1544. Today the Sakurajima radish can grow to 3 feet when left in the ground.