Agronomic and quality effects in winter wheat of a gene conditioning resistance to wheat streak mosaic virus

Abstract

Wheat streak mosaic virus (WSMV) is one of the most important diseases limiting winter wheat (Triticum aestivum L.) production in the western Great Plains of North America. There is no known effective WSMV resistance within the primary gene pool of wheat. However, a resistance gene (Wsm1) has been transferred to wheat from a perennial relative, intermediate wheat-grass [Thinopyrum intermedium (Host) . Nebraska-adapted winter wheat lines carrying Wsm1 were used to characterize the effects of this alien introgression on agronomic and quality traits. Sister-lines from six breeding populations were evaluated under virus-free conditions, and under a naturally occurring viral infection. In uninfected locations, no significant difference for grain yield was detected between resistant (R) and susceptible (S) lines, when averaged over populations, but resistant lines had significantly higher test weights. Within populations, significantly higher grain yield was observed only in population 1, while significantly higher test weights occurred in populations 1, 2, 5 and 6. At the infected location, resistant lines were significantly higher in yield in five of six populations. In two of six populations, susceptible lines were significantly higher in bread loaf volume and bake mix time, while in the remaining populations, no significant quality differences were observed. As the Wsm1 gene provided yield advantages under viral infection, and there was no yield detriment in the absence of the virus, its deployment in hard winter wheat cultivars merits consideration.

Introgression of chromosome segments from multiple alien species in wheat breeding lines with wheat streak mosaic virus resistance

“…Lines were originally scored in 2002 for response to natural infection by WSMV at Hays, KS USA and Sidney, NE, USA (Divis et al, 2006). Visual subjective assessment of the degree of chlorosis and plant stunting were used (Table 1 and footnotes).…”

“…Infected plants show greenish yellow streaks and chlorosis with stunted growth, low root biomass, reduced water uptake efficiency and low yield (Thomas et al, 2004;Price et al, 2010). Both WSMV and the mite vector survive during the late summer on 'green bridges' provided by volunteer wheat and other susceptible wild and cultivated grasses (Divis et al, 2006). As viral diseases cannot be controlled directly by agrochemicals, management of insect vectors and agronomic conditions must be used.…”

“…The present study used genomic in situ hybridisation (GISH; Schwarzacher et al, 1992) complemented by targeted DNA markers and field evaluation to characterize resistance in Nebraska-adapted winter wheat lines originating from four genetically diverse populations that include the Kansas WSMW-resistant Th. intermedium lines in their pedigree, and where resistant and susceptible sister lines are available within populations (Divis et al, 2006). Table 1 lists the wheat lines used in this study and pedigrees where known.…”

“…Reference WSMV-resistant (R) lines KS95H102 and KS96HW10-1 both carrying the Wsm1 gene (Divis et al, 2006;Graybosch et al, 2009) and susceptible (S) lines 'Millennium' and 'Tomahawk' were used as controls. Experimental lines previously classified as R or S to WSMV (Divis et al, 2006) were derived from four breeding populations, designated here as populations I, II, III and IV (Table 1). Mace (PI 651043; Graybosch et al, 2009) was derived from population III and was tested as N02Y5117.…”

Remote Monitoring of Wheat Streak Mosaic Progression Using Sub-Pixel Classification of Landsat 5 TM Imagery for Site Specific Disease Management in Winter Wheat

“…As the disease progresses, infected plants exhibit extreme chlorosis and stunting, and in severe cases chlorotic leaves become necrotic and the plant eventually dies [2,[10][11][12][13]. Symptom severity also depends on wheat cultivar, time of infection, temperature, and other environmental conditions that affect vector populations and plant growth [14]. Since its first discovery in 1922 in Nebraska, WSMV has periodically caused severe epidemics, across most of the Great Plains of the United States [3,8,15].…”