Welcome to the INDIANA REGIONAL SECTION of IFT!
Bruce Applegate , Indiana Section IFT Chair
GMOs, grapes, lack of sex, and bananas cont.
In my last chairman's corner I pointed out that the seedless grape is the result of genetic mutation, which causes the seeds not to form in the fruit. The plants are sterile and can be propagated using vine cuttings. This sterility associated with lack of seeds and propagation does not allow genetic diversity in the seedless grapes. It is also interesting to note that most bananas currently produced worldwide are a hybrid of two Asian varieties. These varieties are seedless since bananas with seeds are inedible. As in the example of the grape these plants can be propagated in a manner without the need for seeds which result from sexual reproduction. Bananas are capable of asexual reproduction which allows for efficient cultivation and dissemination of the seedless variety. These attributes of the (seedless) banana makes them commercially appealing. It also is leading to their potential eradication. As in the grape and many new GMO crops there is a lack of diversity in the plants, making them susceptible as a group to pests and disease. An example of this is the black Sigatoka fungus which attacks the leaves of the banana plant. First isolated in Honduras , it has continued to spread steadily throughout South America .
The sterility of the banana plants does not allow traditional methods of finding a resistant plants and crossing them with other varieties to produce hybrids, similar to plant breeding resulting in higher yield corn. Since the majority of bananas are grown by small farmers and locally consumed, there is not a great concern for the plight of the sexless fruit. However recently there is an effort underway to sequence the banana genome to provide information to aid in preserving this fruit, which astonishingly is the fourth on a list of most important crops following maize, wheat, and rice. The sequence information should provide insight into ways of creating more resistant varieties to insure the plants survival. The example of the plight of the banana also suggests the possible drawback of GMOs in lack of genetic diversity. (This corner was inspired by David Gonzalez a Ph.D student in Agricultural and Biological Engineering who lead a discussion on the subject in a Food Biotechnology class at Purdue.)