|Evett, Steven - Steve|
Submitted to: Plant Disease
Publication Type: Peer reviewed journal
Publication Acceptance Date: 2/21/2010
Publication Date: 6/1/2010
Citation: Price, J.A., Workneh, F., Evett, S.R., Jones, D., Arthur, J., Rush, C.M. 2010. Effects of wheat streak mosaic virus on root development and water-use efficiency of hard red winter wheat. Plant Disease. 94(6):766-770. Interpretive Summary: The semi-arid High Plains states of Colorado, Kansas, Nebraska, New Mexico, Oklahoma, and Texas produced approximately 19 million tons of wheat in 2007, or 28.3% of the total U.S. wheat crop. The High Plains is a semi-arid region, and approximately 2.5 million acres of wheat are irrigated with water from the Ogallala aquifer, which underlies 111 million acres in the states of Colorado, Kansas, Nebraska, New Mexico, Oklahoma, South Dakota, Texas, and Wyoming. One of the most important wheat diseases throughout the High Plains region is wheat streak mosaic (WSM) virus. Although the adverse effects on forage and grain yields have been recognized for years, little was known about the effects of the disease on plant root development and water use efficiency (WUE). Texas AgriLife Research, with assistance of the USDA-ARS Soil and Water Conservation Research Unit, conducted a study to determine the effects of WSMV on root development and WUE of hard red winter wheat. Important reductions in forage, grain yield, and crop WUE, as well as significant increases in soil moisture were found due to WSM virus. Even when additional irrigation water was applied, no significant increases in root and shoot weights, above-ground biomass, or grain yield were observed in either the greenhouse or field studies when infected by WSM virus. Results indicate that addition of irrigation water to severely diseased wheat constitutes a waste of time, energy, and natural resources. This finding is important because new precision irrigation control technologies will recognize infected wheat as water stressed, which will lead to an incorrect signal to irrigate. Therefore, sensing technology should be developed to discriminate between healthy water-stressed wheat, which should be irrigated, and infected wheat, which should not be irrigated.
Technical Abstract: Greenhouse and field studies were conducted to determine the effects of Wheat streak mosaic virus (WSMV), a member of the family Potyviridae, on root development and water-use efficiency (WUE) of two hard red winter wheat (Triticum aestivum) cultivars, one susceptible and one resistant to WSMV. In the greenhouse studies, wheat cultivars were grown under three water regimes of 30, 60, and 80% soil saturation capacity. After inoculation with WSMV, plants were grown for approximately 4 weeks and then harvested. Root and shoot weights were measured to determine the effect of the disease on biomass. In all water treatments, root biomass and WUE of inoculated susceptible plants were significantly less (P < 0.05) than those of the noninoculated control plants. However, in the resistant cultivar, significance was only found in the 30 and 60% treatments for root weight and WUE, respectively. Field studies were also conducted under three water regimes based on reference evapotranspiration rates. Significant reductions in forage, grain yield, and crop WUE were observed in the inoculated susceptible plots compared with the noninoculated plots. Both studies demonstrated that wheat streak mosaic reduces WUE, which is a major concern in the Texas Panhandle because of limited availability of water.