More Wheat Options for Organic Producers May Be on the Horizon

RALEIGH, North Carolina – North Carolina organic wheat producers who face challenges in controlling stubborn weeds, specifically Italian ryegrass, may soon be able to choose from varieties that suppress those weed populations.

North Carolina State University graduate student Margaret Worthington is studying 60 soft red winter wheat cultivars from public and private breeding programs for morphological characteristics and allelopathic traits that would help the wheat plants out-compete Italian ryegrass. The research, “Breeding Wheat for Increased Weed-Suppressive Ability Against Italian Ryegrass (GS12-115),” is being funded by a two-year, $10,952 Southern Sustainable Agriculture Research and Education (SSARE) Graduate Student Grant.

“The goal of the project is identify wheat varieties that can out-perform Italian ryegrass in the field while not compromising yields, so that organic and conventional wheat growers have options available to them to control weeds that don’t involve chemical applications,” said Worthington. “Through this work, we can develop improved breeding protocols that will enable public sector wheat breeders across the Southeast to select for lines with enhanced allelopathy and morphological traits conferring weed suppressive ability.”

Morphological traits include early vigor, height, leaf area index, and tillering. Allelopathy refers to biochemicals produced by one plant that inhibit the performance of another plant.

NCSU wheat cultivar trials. Photo courtesy of NCSU.

Worthington said that identifying weed-suppressive wheat varieties for Italian ryegrass is extremely important to both the organic and conventional ag industries. Italian ryegrass, also known as annual ryegrass, is a common weedy winter annual in small grain crops in the Southeast. It reduces grain yield by competing for nutrients and light, decreases the number of productive tillers, and promotes lodging.

“Controlling Italian ryegrass is a challenge for both the organic and conventional producer. The biggest issues are the cost of herbicides and the expansion of herbicide-resistant Italian ryegrass populations,” said Worthington. “Organic farmers must achieve near total weed control before planting through mechanical cultivation with a rotary hoe or tine weeder, narrow row spacing, and high density planting. Severely infested fields are often taken out of organic wheat production for many years, as few management options are available for Italian ryegrass control.”

Worthington said that interest in organic wheat production in North Carolina is increasing as more livestock producers seek a local source for organic grain, and as more consumers ask for more organic artisanal bread products.

“Through organic variety tests, we hope to recommend to growers commercially available varieties with good weed-suppressive abilities and high yields,” she said.

Prior to this SSARE-funded research, Worthington, NCSU crop science professor Paul Murphy, and assistant professor Chris Reberg-Horton conducted pilot studies to develop screening methods for weed-suppressive ability that would be appropriate for use in a large breeding program.  They will build upon those studies by screening locally adapted cultivars in replicated field trials beginning this winter.

Preliminary work indicates that cultivars with high vigor during tillering and early heading dates show promise. 

--30—

Published by the Southern Region of the Sustainable Agriculture Research and Education (SARE) program. Funded by the USDA National Institute of Food and Agriculture (NIFA), Southern SARE operates under cooperative agreements with the University of Georgia, Fort Valley State University, and the Kerr Center for Sustainable Agriculture to offer competitive grants to advance sustainable agriculture in America's Southern region.