Each variety of crop seed possesses its own set of characteristics. Some varieties of apple seeds, for example, are
more resistant to disease than others. Some yield fruit with higher nutritional value. Others are more adaptable
to diverse climates. As time goes on, many seed varieties are lost. For example, at the turn of the century, the U.S.
grew nearly 8,000 varieties of apples. Today, more than 95 percent of those varieties are no longer extant. This
worries many experts, who have stressed that the world's variable conditions require us to store a large variety of
seeds and that diversification may be necessary to support a rapidly growing world population.