Answer to the Friday Whatsit for March 4, 2011
Congratulations to Aunt Linda and Murph! This is a close up of an orange turned black and white to hide its identity.
According to the New Crop website from the Purdue University’s Agriculture section, the sweet orange (Citrus sinensis or Citrus aurantium var. sinsnsis) isn’t found in nature. It was developed by humans hundreds of years ago from the sour or bitter orange (Citrus aurantium) which is found in the wild as a native of Southeast Asia. Some now consider the sweet orange its own distinct species, while others still consider it a variety of the bitter orange (hence the two different Latin names).
Sweet oranges are best grown in sub-tropical regions of the world and are cultivated either from seed or, in the case of seedless oranges and some other varieties, by grafting small pieces of sweet orange branches (known as scions) onto bitter orange rootstock. The roots are then the stronger bitter orange stock, but the branches produce sweet oranges. This process has been used for centuries with fruit trees like apple, cherry and avocado. It can also be done with vines or herbaceous crops (tomato, eggplant, and watermelon for example) as a way to grow the produce from a disease or pest-susceptible plant on the roots of a heartier, more disease or pest-resistant cousin.