EFFECT OF SUGARCANE MOSAIC-VIRUS ON THE YIELD OF 11 GRAIN-SORGHUM (SORGHUM BICOLOR) CULTIVARS

The effect of a Johnson grass strain of sugarcane mosaic virus (SCMV-Jg) on 11 grain sorghum cultivars was assessed in three experiments in which young plants were inoculated with the virus. The 11 cultivars were Alpha, Dekalb B17, Dekalb C42t, Dekalb C42Y, Dekalb E57, Goldrush, Pride, 051 61, Q5161 VR, Tx6I0SR and Yates 233. Severe yield depression (>50%) was observed in those cultivars that developed the red stripe and red leaf symptoms. The effect on cultivars producing mosaic symptoms ranged from tolerance (Tx610SR) to yield losses of ca 25%. Yield depression was primarily due to fewer grains per panicle and reduced grain weight. The number of panicles per ha was the least affected of the yield components. In most instances, the disease delayed maturity and decreased height. A virus-resistant cultivar (Q5161 VR) showed an increase in yield when inoculated with SCMV-Jg. © 1979 ASEG.