甘蔗梢腐病田间抗性评价体系的建立

Establishment of an evaluation system for field resistance against sugarcane pokkah boeng

【目的】探讨甘蔗梢腐病田间分级标准和品种（系）区域性抗病差异。【方法】以11个甘蔗新品种（系）和广西当前主栽品种ROC22在南宁、柳州、河池、百色、北海和崇左6个试验点梢腐病的发病情况为依据,建立甘蔗梢腐病田间病害分级标准及品种（系）抗性评价体系。【结果】参试点新植蔗梢腐病发病率为0.16%~23.82%（平均为3.51%）,病情指数为0.03~16.48（平均为3.45）,宿根蔗梢腐病发病率为0~25.89%（平均为4.27%）,病情指数为0~17.37（平均为4.61）。建立了田间抗性评价标准,并将抗性水平划分为高抗、抗病、中抗、中感、感病和高感6个不同抗性等级。研究的12个品种（系）中没有发现高抗和高感材料,其中桂辐06-156、桂糖05-3846、桂选B9和ROC22抗性最好,表现为抗性;桂糖06-1023和桂糖06-400抗性最差,均表现为感病。根据病情指数对12个材料进行聚类分析,结果显示,不同甘蔗品种（系）的聚类与抗性等级划分的结果一致。梢腐病在广西蔗区的发生呈现区域性,崇左、柳州和河池3个试验点属于梢腐病重发区;北海次之;百色和南宁2个试验点属于轻发区。【结论】不同甘蔗种植区域、不同品种（系）以及不同植期存在感抗梢腐病差异性。

[ Objective ] To discuss the field grading standard on sugarcane pokkah boeng disease severity, and study regional and varietal （elonal） differences in occurrence of pokkah boeng disease. [ Method ] The occurrence of pokkah boeng disease on 11 new sugarcane varieties （lines） and the dominant cultivar ROC22 in Guangxi was investigated in six sites including Nanning, Liuzhou, Hechi, Baise, Beihai and Chongzuo cities. The grading standard on sugarcane pokkah boeng disease and the resistance evaluation system were established. [ Result ] The incidence and disease severity index （DSI） of new-planting sugar- cane were 0. 16% - 23.82% （ average 3.51% ） and 0. 03 - 16. 48 （ average 3.45 ） respectively, and those of ratoon cane were 0 -25.89% （average 4. 27% ） and 0 - 17.37 （average 4.61 ）. According to the new standard, six resistance grades were established, including high resistance （HR） , resistance （R）, medium resistance （MR）, medium susceptible （MS）, susceptible （S） and high susceptible （HS）. HR and HS sugarcane varieties （clones） were not found in the 12 tested materials. Among the 12 varieties, Guifu06-156, Guitang05-3846, GuixuanB9 and ROC22 belonged to R grade and demonstra- ted the highest resistance against pokkah grade with the lowest resistance. The 12 boeng disease, and Guitang06-1023 and Guitang06-400 were S tested sugarcane varieties （clones） were clustered according to the DSI, and the result agreed with that of resistance grading. The incidence of pokkah boeng disease showed regional difference in Guangxi. The sugarcane areas of Chongzuo, Liuzhou and Hechi were the most serious, followed by Beihai, and Baise and Nanning were the least serious. [ Conclusion ] There were distinct differences among different sugarcane areas, among varieties （lines） and among planting sea- sons regarding the susceptibility and resistance against pokkah boeng disease.