ENVS 1000 Lecture Notes - Lecture 11: Mutation Breeding, Calrose Rice, Norman Borlaug
13 Dec 2016
School
Department
Course
Professor
ENVS: Agriculture and Food
Improved Crops
● Mendelian Genetics:
○ Possible to manipulate traits with predictable outcomes but limited capacity to
really change crops
● Artificial Pollination (pre 1900’s):
○ Deliberate addition of pollen to some plants with the intent of passing along traits
● Biologists expose crops to x-rays to stimulate mutations
● Mutation Breeding:
○ Exposes seed to radiation or chemicals that induce mutations-then test for rare
positive outcomes-
○ One way to accelerate mutations
○ Crops produced through mutation breeding:
■ Rice: Calrose 76
■ Grapefruit: Star Ruby
■ Lettuce: Ice Cube
● Wheat:
○ Most natural wheats are tall, when fertilized they get really tall and flop over
○ Why is that a problem?
■ Wheat gets moldy
■ Animals can eat it more easily
■ Can’t harvest it effectively
○ Norman Borlaug:
■ 1950’s:
● Worked with a wheat strain with gene for short stature
● Crossed this variety with other tropical varieties and developed
semi-dwarf wheats
■ Wheat yields are 4 times higher today than in 1930
● Pest Control:
○ Historically:
■ Mechanical Control or non-specific application of chemicals
■ Addition of copper or other toxic metals
○ Modern:
■ Engineered specifically to target pests
■ Organochlorine:
● Target sodium ion channels in nerve cells of insects
■ Organophosphates:
● Block electrical transmissions across nerve cells
Global Hunger
Problem with Protein:
● It takes 5-20 times the resources to provide 100 calories of meat as it does to provide
100 calories of grain
● Meat protein is expensive
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
Possible to manipulate traits with predictable outcomes but limited capacity to really change crops. Deliberate addition of pollen to some plants with the intent of passing along traits. Biologists expose crops to x-rays to stimulate mutations. Exposes seed to radiation or chemicals that induce mutations-then test for rare positive outcomes- Most natural wheats are tall, when fertilized they get really tall and flop over. Worked with a wheat strain with gene for short stature. Crossed this variety with other tropical varieties and developed semi-dwarf wheats. Wheat yields are 4 times higher today than in 1930. Mechanical control or non-specific application of chemicals. Addition of copper or other toxic metals. Target sodium ion channels in nerve cells of insects. It takes 5-20 times the resources to provide 100 calories of meat as it does to provide. Meat production requires extensive use of grain, which then means the grain is not available to eat.
