Agronomy: The Benefits of Sowing Wild Oats

To the ancient Hebrews, the grain rust that so often attacked their crops was nothing less than God’s punishment for their sins. The Romans, who knew the same agricultural scourge, placed a special god in charge of it and prayed to him for mercy. In King Lear, Shakespeare blamed rust’s presence on a “foul fiend” named Flibbertigibbet. Whatever its origin, the fungus is still thriving; its red, yellow and orange splotches on stems and leaves cause a grain-crop loss of hundreds of millions of dollars every year. And every time that modern agronomists breed a resistant grain, within a decade or so a new and devastating rust develops through natural mutation.

A recent mutant, oat rust 264, has been one of the nastiest of all, defying all efforts at control. Now, after a long search, the Israeli scientist who first identified the virulent fungus back in 1953 has not only found a wild strain of 264-proof oats, he has a plan that will enable farmers to prepare for the inevitable appearance of the next new deadly mutant.

Survival of the Fittest. Financed by a grant from the U.S. Agriculture Department, Plant Pathologist Isaac Wahl began his search for resistant oats in Israel—on the theory that the varieties of wild oats growing there must have built up some sort of immunity. “In the process of evolution over millions of years,” he explains, “the survival of the fittest applies to cereal grains, too.”

Scouring the Israeli countryside for four years, he collected 2,350 samples, inoculated them with rusts and put them through rugged environmental tests in hothouses and in the fields. The most promising 100 samples were sent to the U.S. Agriculture Department; along with 4,000 resistant selections from other countries they were subjected to 264 and other strains of rust. From the fierce competition, a strain of wild oats that Wahl had found near Israel’s Mount Carmel emerged the winner.

A Troublesome Trait. Designated 6-105 by the Agriculture Department, the new wild oat, which has a high protein value, resists the rusts that destroy 6% of the U.S. oat crop every year. To eliminate its tendency to lose some of its kernels before harvesting, it is currently being bred with existing commercial varieties at Agriculture Department stations in Midwestern and Southern states. When that troublesome trait is eliminated and varieties bred from 6-105 finally go into large-scale production, they could save the U.S. farmer upwards of $26 million per year.

Against the day when 6-105 and other thriving strains fall victim to new mutants of rust, Wahl is already working with Israeli Geneticist Daniel Zohary to breed fungi-resistant grain strains that will, like plasma in a blood bank, be immediately available for sowing in areas hard-hit by rust epidemics. They have already found new wheat and barley strains that are apparently resistant to rust. Says Wahl: “We must build up a bank rich in strains so that we are never again caught by a scavenger like 264.”