1. Back to the Future of Cereals
Current Issues in Biology, Volume 3
Scientific American

2. Back to the Future of Cereals
Concept Review
Cereal crops include rice, wheat, corn, millet, barley, sorghum, and barley.
Cereal crops supply the bulk of our food.
Crop yield must be increased 1.5% per year to keep up with population growth.

3. Back to the Future of Cereals
Concept Review
Our ancestors created the crops we know by artificial selection of desirable traits; this process has been refined by modern plant breeders.

4. Back to the Future of Cereals
Concept Review
Selective breeding has profound effects.
Corn and its wild relative, teosinte.

5. Back to the Future of Cereals
Concept Review
Conventional plant breeding may not be enough to continue necessary increased yields.
New methods based on modern genetics give hope for the future.

6. Back to the Future of Cereals
Concept Review
Modern crops have little genetic diversity.
Improvements in modern crops may come from tapping into the genetic wealth of their wild ancestors.
Alleles from wild varieties produce dramatic and often unexpected changes in modern crop varieties.
For example, alleles from a green wild tomato introduced into a pale red commercial variety created a redder hybrid.

7. Back to the Future of Cereals
Concept Review
Marker-assisted breeding is a new method that allows introducing select alleles into modern crops.
Marker-assisted breeding.

8. Back to the Future of Cereals
Concept Review
Marker-assisted breeding.

9. Back to the Future of Cereals
Concept Review
One success of marker assisted breeding is a 17% increase in rice yield by introducing alleles from a wild rice relative into a modern crop variety.
Marker-assisted breeding and other techniques made possible by modern genetics may be the best hope for continuing needed increases in crop yield.

10. Back to the Future of Cereals
Testing Your Comprehension
In comparison to their wild relatives, modern crop plants have
a) low yields.
b) low genetic diversity.
c) more genes.
d) few genetic markers.

11. Back to the Future of Cereals
Testing Your Comprehension
In comparison to their wild relatives, modern crop plants have
b) low genetic diversity.

12. Back to the Future of Cereals
Testing Your Comprehension
To feed the world’s growing population, crop yields must be increased ______ percent each year.
a) 0.01
b) 0.1
c) 1.5
d) 6.7

13. Back to the Future of Cereals
Testing Your Comprehension
To feed the world’s growing population, crop yields must be increased ______ percent each year.
c) 1.5

14. Back to the Future of Cereals
Testing Your Comprehension
The method that allows researchers to tailor crops so they contain only desired alleles is
a) trait mapping.
b) homology searching.
c) expression profiling.
d) marker-assisted breeding.

15. Back to the Future of Cereals
Testing Your Comprehension
The method that allows researchers to tailor crops so they contain only desired alleles is
d) marker-assisted breeding.

16. Back to the Future of Cereals
Biology and Society
Instead of working to increase crop production by developing ever more specialized crop varieties, we should simply use more of our current crops for food instead of for animal feed and industrial products.
The intent of the question is to have students think about potentially simple solutions to complex problems. Maybe completely changing U.S. agriculture and consumer habits would allow us get away from the need for continuous increases in yield. But at what cost? The question may reveal sharply contrasting political views and lifestyle choices within a class.
Strongly
Agree
Disagree A. E. C. B. D.

17. Back to the Future of Cereals
Biology and Society
The development of more genetically engineered crops is essential if we are to feed a hungry world.
Strongly
Agree
Disagree A. E. C. B. D.

18. Back to the Future of Cereals
Biology and Society
The kinds of plants developed from marker-assisted plant breeding are no more threatening than crops developed by conventional methods of plant breeding.
Strongly
Agree
Disagree A. E. C. B. D.

19. Back to the Future of Cereals
Thinking About Science
Synteny is the sharing of genes and gene organization between different species. How does the high degree of synteny between rice, wheat and corn benefit plant breeders striving to improve these crops?
a) It provides a large number of genes for breeders to use for crop improvement.
b) It allows genetic insights gained in one crop to be easily applied to another.
c) It reduces the number of generations required for successful marker-assisted breeding.
d) It provides many genetic markers for efficient marker-assisted breeding.

20. Back to the Future of Cereals
Thinking About Science
Synteny is the sharing of genes and gene organization between different species. How does the high degree of synteny between rice, wheat and corn benefit plant breeders striving to improve these crops?
b) It allows genetic insights gained in one crop to be easily applied to another.

21. Back to the Future of Cereals
Interpreting Data and Graphs
Roughly how much more is the projected required corn yield for 2050 than the yield in year 2000?

22. Back to the Future of Cereals
Interpreting Data and Graphs
The projected required corn yield for 2050 is roughly 2.2 times greater than the yield in year 2000 (9,000 kg/hectare in 2050 vs. 4,000 kg/hectare in 2000).