荔枝果实对霜疫霉侵染抗性评价体系建立及初步应用

摘要

为建立稳定的荔枝果实对霜疫霉侵染抗性评价体系,研究不同浓度孢子囊悬浮液浸染、不同症状调查时间对不同荔枝品种病情指数的影响,并用建立的方法研究部分荔枝品种对霜疫霉侵染抗性的初步评价.结果表明:以4×104个/mL孢子囊浓度悬浮液为接种浓度,‘妃子笑’和‘大丁香’离体果实病征发生速度适中,侵染第72小时的病情指数比较稳定,能够更好地区分品种间的抗病性差异.2012～2016年,用该指标体系先后评价了15个荔枝品种对霜疫霉侵染的抗性,结果发现不同年份这些品种的抗性分级基本相同,‘黑叶’和‘桂味’是表现最为稳定的抗病和感病品种,证实了建立的抗性评价体系的稳定性.%In order to establish a stable resistance evaluation system of litchi fruit to downy blight,the influence on disease index (DI) of concentration of inoculation sporangia and time of record for symptom were studied among different litchi germplasms.The results showed that the disease symptom of ‘Feizixiao'and ‘Dadingxiang'inoculated with 4×l&/mL sporangia occurred at moderate speed,and the disease index of 72 h was relatively stable,which was a proper time of symptom survey for resistance to downy blight of litchi.During 2012-2016,the system was applied to evaluate the resistance to downy blight among 15 litchi cultivars.The resistance grades of these cultivars were almost the same in different years,and ‘Heiye'and ‘Guiwei'was the most stable resistant and susceptible cultivars,respectively.These confirmed that the resistance evaluation system of litchi fruit to downy blight was stable.