不同柑橘属种质对柑橘褐斑病菌的抗性评价

Evaluation of Citrus germplasm resistance to Alternaria alternata

【目的】探讨不同柑橘种质及‘梨橙2号’ב晚蜜2号’部分杂交种对柑橘褐斑病菌Alternaria alternata的感病程度及抗性分级标准。【方法】采用室内果实去皮接种观察不同种质的感病程度并根据系统聚类分析法、病斑平均直径法、病情指数法3种抗性评价方法对抗病性进行分级。【结果】大部分宽皮柑橘类种质易感病;甜橙类、柚类和柠檬类种质较抗病。参试的54份种质划分为高抗、抗病、中抗、感病、高感5类,未发现免疫种质;‘胡柚’、‘强德勒’、‘华盛顿脐橙’和‘梁平柚’4个品种为高抗品种。‘梨橙2号’ב晚蜜2号’杂交种抗病性出现分离,可以进行遗传分析。【结论】宽皮柑橘种质及其杂交种和葡萄柚易感病。

【Objective】To identify the resistance of citrus germplam and some F1 hybrids of Citrus sinensis‘Licheng No. 2＇×C. reticulata‘Wanmi No. 2＇to A. alternata and to evaluate different methods for assess-ment of the resistance to Alternaria alternata.【Methods】The partially peeled fruits were inoculated withA.alternata and kept in a humidified box at 25 ℃ for 3 days to survey the severity of the disease. The resis-tance was evaluated with the methods of disease system clustering analysis,average diameter of thespeckle and disease index method.【Results】Most C. reticulata（tangerine） varieties and F1 hybrids weresusceptible. C. sinensis,C. grandis and C. limon were highly resistant. The fifty-four varieties could beclassified into five categories of highly resistant,resistant,moderately resistant,susceptible and highlysusceptible. None of the varieties was found to be immune. Huyou pomelo,Chandler pomelo,Washing-ton navel orange and Liangping pomelo showed high resistance. The segregation on disease resistance wasobserved among the F1 hybrids of C. sinensis‘Licheng No. 2＇×C. reticulata‘Wanmi No. 2＇.【Conclusion】The results demonstrated that C. reticulata（tangerine） varieties and its hybrids as well as C. paradisi aremore susceptible to citrus brown spot disease compared to the C. sinensis,C. grandis and C. limon.