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Promising corn varieties from Texas AgriLife fight aflatoxin

The war against aflatoxin is tough. But Texas AgriLife Research scientists showcased promising hybrid corn varieties to a group of producers and industry representatives recently at field trials just outside College Station.

Aflatoxin is a poison produced by a fungus that grows in corn during periods of hot and dry weather.

At least $14 million in losses due to corn mycotoxins have been recorded for Texas producers, but the losses to Texas agriculture likely are closer to $200 million, said Seth Murray, AgriLife Research corn breeder.

Murray and members of the project team said they were optimistic about the work they’ve done, giving the group a firsthand look at the AgriLife Research and Texas AgriLife Extension Service field trials in the Brazos bottom.

“The main areas where aflatoxin has been a problem is in south-central and the eastern part of Texas,” Murray noted.

Key Points

• Specialists seek solutions to reduce aflatoxin contamination.

• Aflatoxin has led to multimillion-dollar losses in corn production.

• Losses exceeding $14 million a year have hurt Texas corn growers.

Fend off aflatoxin

Breeding corn varieties that fend off the aflatoxin threat is complicated, Murray said. Factors include yield, husk coverage and maturity traits, such as kernel hardness and earworm resistance.

“Numerous traits are controlled by numerous genes,” he said. “The only way to pyramid these genes is to crossbreed and cross-pollinate with the goal of developing varieties better adapted to Texas.”

Tom Isakeit, AgriLife Extension plant pathologist, College Station, gave an overview of inoculation techniques used in the breeding nursery to more effectively evaluate aflatoxin resistance.

Methods include injecting spores of the fungus into a wound in the side of the ear, or injecting spores through the tip of the ear, without wounding.

Another experimental method used in trials is to spread kernels of infected corn onto the ground during flowering.

Corn from the breeding nursery trials is evaluated for aflatoxin by a chemical test or with near-infrared spectroscopy, Isakeit said.

One commercial product, Aflaguard, has had mixed results in his trials. Aflaguard consist of spores of a non-toxic fungus that prevent infection of the corn by the toxic strains.

The treatment led to a 42% reduction in aflatoxin on one small-scale experiment. But in a larger experiment, it did not seem to have any effect, Isakeit said.

Lubbock work

Wenwei Xu, AgriLife Research corn breeder at Lubbock, also is doing important corn work.

“We’re trying to improve drought tolerance and make it less attractive for insect populations,” Wu said. “Another area of study is improving irrigation, reducing the amount of water needed annually to irrigate corn crops.”

Among varieties showcased, an experimental line, labeled S2B73BC crossed with a University of North Carolina line NC300, featured genes that were 25% tropical and with a deep-rooted system.

“This line has featured excellent drought tolerance and low aflatoxin,” said Kerry Mayfield, research associate. “It has a good root, goes really deep into the soil, which helps the plant stand up tall, and will not blow over. This also helps the ears from falling over on the ground and getting wet.”

Another line, B5C X NC300, was developed for silage, also making it a prime candidate for the biomass industry, Murray added.

“It is a very good line that has done well throughout the U.S.,” he told the group. “It has excellent silage yield and is 50% tropical with good root growth.”

For more about the research program, go online to maizeandgenetics.
tamu.edu.

Fannin is with Texas A&M Agriculture Communications, College Station.

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HELP coming for corn: Texas AgriLife Research and Texas AgriLife Extension Service specialists are finding solutions to breed better corn varieties that fend off aflatoxin, along with having other improved traits.

This article published in the September, 2010 edition of THE FARMER-STOCKMAN.

All rights reserved. Copyright Farm Progress Cos. 2010.