Cereals and Pseudocereals
Barley ‘Mesa’ – Russian Wheat Aphid Resistance
DEVELOPMENT OF THE WINTER FEED BARLEY CULTIVAR ‘MESA’ (HORDEUM VULGARE) WITH RESISTANCE TO THE RUSSIAN WHEAT APHID
Patrick F. Byrne and Dolores W. Mornhinweg
Department of Soil and Crop Sciences, Colorado State University, 307 University Ave, Fort Collins, Colorado 80523.
USDA-ARS Peanut and Small Grains Research Unit, 1301 N Western Rd, Stillwater, Oklahoma 74075.
Corresponding author<EMAIL_ADDRESS>OUTLINE
1. SUMMARY
Russian wheat aphid (RWA, Diuraphis noxia (Kurdjumov)) infestation is a serious constraint to winter barley (Hordeum vulgare) production in the western U.S. An Iranian landrace with RWA resistance was crossed to the adapted U.S. cultivar ‘Schuyler’ (Jensen, 1972), followed by multiple backcrosses. Resistant plants were selected in Oklahoma and evaluated in field trials in Colorado and Idaho. ‘Mesa’ was the superior line in those trials and was released for production in 2017 (Mornhinweg et al., 2017). Mesa, a 6-rowed winter habit feed barley, is classified as highly resistant to RWA and yields as well as its parent Schuyler, both in the presence and absence of RWA pressure.
The goal was to develop a line of commercially viable winter barley that could withstand Russian wheat aphid infestations.
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2. PROBLEMS ADDRESSED
Following its introduction in 1986, RWA spread rapidly in the western U.S., resulting in reduced grain yield and quality (Mornhinweg et al., 2006). Winter barley had previously been grown as a feed crop and an important rotation crop with wheat (Triticum aestivum), but its production declined drastically due to susceptibility to RWA (Mornhinweg et al., 2017). All U.S. barley cultivars were susceptible to RWA. Four resistant feed cultivars were developed and released by USDA-ARS scientists in Stillwater, Oklahoma and Aberdeen, Idaho; however, they were 2-rowed spring habit barleys that filled a different cropping niche. The RWA problem became more complicated with the appearance of new biotypes of the insect; there are now at least eight recognized biotypes with differential virulence against barley and wheat varieties (Mornhinweg et al., 2017). Thus, a 6-rowed winter barley was needed with competitive yield and a high level of resistance to multiple RWA biotypes.
3. SOLUTIONS DEVELOPED
The resistant but unadapted barley germplasm line R017 from the National Plant Germplasm (NPGS) facility in Aberdeen, Idaho was crossed to the adapted cultivar Schuyler, followed by three backcrosses to the adapted parent. After each backcross, plants were screened for resistance and resistant plants were used for the next backcross (Webster et al., 1991). 171 resistant lines were identified and evaluated in Fruita, Colorado for agronomic adaptation and yield performance. Additional yield testing occurred in Idaho and in multistate trials (Mornhinweg et al., 2017). Mesa (PI 659768) was selected as the superi