关键词: 稻曲病, 病情分级, 标准

Abstract: The relationships between per panicle weight loss rate and per panicle’s number of rice false smut ball and diseased grains were calculated, respectively. The results indicated that there were significantly negative correlation between panicle weight and per panicle smut ball numbers and diseased grains. According to the per panicle smut ball numbers, rice false smut grading standard was determined: grade 0, 1, 2, 3, 4 and 5 corresponding to 0, 1, 2, 3, 4~5 and more than 6 （including 6）smut balls per panicle. On the other hands, according to the per panicle diseased grain numbers, rice false smut grading standard was determined: grade 0, 1, 2, 3, 4 and 5 corresponding to 0, 1, 2~3, 4~6, 7~13 and more than 14 （including 14） infected grains per panicle. The authors suggested that per panicle smut ball numbers should be adopted for grading standard of rice false smut in investigation in the field. Nevertheless, it was better by using per panicle diseased grain numbers as grading standard of rice false smut in the experiments and demonstration projects.

Key words: rice false smut, grading of disease severity, standard