Why do some individual plants live longer in the field after others died off? Why do some individual plants yield better? Why do some naturally resist disease that destroys others?
These types of questions are best exemplified by the history of rust-resistant Selkirk wheat.
In 1930, Moseph McMurachy found two heads of rust-free wheat while harvesting. He sowed the seeds and by 1935 had developed six acres. In 1935, a stem rust epidemic wiped out most wheat in his district. McMurachy’s six acres stood almost untouched. By crossing these samples with other varieties, the Selkirk variety evolved and two decades later 150,000 bushels of clean Selkirk seed had been produced.
Plant pathologists today understand the genetics of why one individual plant resists a disease that destroys the adjacent plant. DNA sequences include a gene that invites disease into the plant. If breeders can find that gene and remove it from the DNA sequence, that plant will no longer invite disease to visit.
One technique for identifying and removing that bad gene is called Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR).
North Dakota State University plant pathologist Audrey Kalil says CRISPR is like having a scissor that can surgically remove the DNA you don’t want. Breeders have developed new varieties of canola and flax and are working on vegetables and other crops.
“Plant scientists are looking for ways to help plants withstand infection,” Kalil said.
“One of the best ways to fight disease is to find plants that seem to have their own natural resistance. These are the plants that are still in the field after others have died or that yield well when others can’t.”
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