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Disease Detection and Losses

Relationship Between Seed Infection by Barley Stripe Mosaic Virus and Yield Loss. F. W. Nutter, Jr., Former graduate research assistant, Department of Plant Pathology, North Dakota State University, Fargo 58105; V. D. Pederson(2), and R. G. Timian(3). (2)(3)Professor, and research plant pathologist (USDA, ARS), respectively, Department of Plant Pathology, North Dakota State University, Fargo 58105. Phytopathology 74:363-366. Accepted for publication 3 November 1983. This article is in the public domain and not copyrightable. It may be freely reprinted with customary crediting of the source. The American Phytopathological Society, 1984. DOI: 10.1094/Phyto-74-363.

Field experiments were conducted in 1981 and 1982 to quantify the effect of barley stripe mosaic virus (BSMV) seed infection levels on grain yield, yield components, kernel protein, and percent seed transmission in barley cultivar Dickson. Barley seed infected with BSMV (strain ND18) was blended with seed free of BSMV to produce infected seed levels of 0, 0.1, 1, 5, 15, 30, 45, and 60%. The number of heads per meter of row and seed weight decreased as percent seed infected with BSMV increased, whereas the number of seeds per head was not greatly affected by BSMV. Reduction in yield per plot, heads per meter of row, and 500-seed weight in response to increasing levels of seed infection by BSMV was best described by a quadratic model in 1981, but by a linear model in 1982. To make yield and yield component loss comparisons between years, the linear model ŷ = b₀ + b₁x, in which ŷ is the predicted response of any yield factor and x is the level (percentage) of seed infection by BSMV, was the most adequate. Regression coefficients relating levels of seed infection by BSMV to reduction in yield per plot, heads per meter of row, seeds per head, and 500-seed weight were greater in 1981 than in 1982. This was most likely the result of environmental conditions favoring greater plant-to-plant spread of BSMV in 1981. The apparent infection rate was greater in 1981 than in 1982 and percent seed transmission of BSMV (an indirect measure of field spread) was also greater in 1981. In 1981, percent kernel protein increased as the proportion of seed infected by BSMV was increased.