Selective Breeding
Approximately twenty plant species provide about 90% of the world's food. All major food crops, including corn, wheat, and soybeans, are becoming more and more genetically modified (GM) and exhibit less and less genetic variation. The crops we grow are drought tolerant and able to withstand herbicide spraying. They are more resistant to insect pests. One wild relative of corn called milpilla or Zea diploperennis, is exceptionally disease-resistant and is the only perennial in the corn family. Zea diploperennis grows on only one mountain in western Mexico.
As scientists have developed more productive crop varieties, farmers have switched from growing many traditional varieties to new high-yield varieties, and the number of corn species being cultivated and farmed has dropped from hundreds to about 20 genetically improved corn varieties worldwide.In selectively breeding corn we have also reduced
Responses
A the corn gene pool.the corn gene pool.
B people's dietary choices.people's dietary choices.
C animal and insect biodiversity.animal and insect biodiversity.
D the number of food chains relying on corn.