THE MUTAGENESIS OF ATTENUATED STRAIN OF TMV DN60-3 AND THE PROTECTIVE EFFECT ON TOMATO MOSAIC DISEASE
Abstract: For the purpose of obtaining attenuated strain of TMV, pure virus isolated from tomato plants with mild symptom were treated with nitrous acid for 30, 40, 50, 60 minutes, as a result, 30 symptomless mutants had been obtained. In cross protection tests on tomato, the attenuated virus DN60-3 interfered more strongly with the severe mosaic strain, the streak strain and the necrosis strain occurred in Jinan (Shandong), whereas interfered weakly with the yellow mosaic strain and the yellow ringspot strain, both ...