甘蔗白叶病抗病性鉴定方法的建立与应用

Establishment and application of the resistance identification method for sugarcane white leaf disease

为建立简便高效、致病性稳定和规范实用的甘蔗抗白叶病鉴定方法,推动甘蔗抗白叶病育种,本文从甘蔗材料处理与种植、接种液配制、接种方式、病情调查、分级标准制定等层面对甘蔗抗白叶病鉴定技术进行了系统研究与探索,首次优化创建了简便高效、致病性稳定和规范实用的甘蔗抗白叶病鉴定方法,即种苗喷雾接种法和生长期切茎接种法。种苗喷雾接种法:直接筛选甘蔗白叶病植原体蔗茎榨汁加10倍量无菌水配制接种液,接种液喷洒蔗种,塑料薄膜保湿,接种材料桶栽置于防虫温室培养,接种种植30 d开始调查病株率,按1~5级标准进行抗病性评价。切茎接种法:直接筛选甘蔗白叶病植原体蔗茎榨汁加10倍量无菌水配制接种液,鉴定材料桶栽置于防虫温室培养,株龄6月时切茎用移液枪将100μL接种液滴入根部切口接种,接种种植20 d开始调查病株率,按1~5级标准进行抗病性评价。两种方法与自然传播相似,接种后发病显著、灵敏度高、重现性好,抗性鉴定结果与田间自然发病相吻合。通过两种接种方法和田间自然发病调查,鉴定明确了10个主栽品种对甘蔗白叶病抗病性,其抗病性真实、可靠,可作为今后甘蔗抗白叶病鉴定标准品种。

This study aims to establish a simple and efficient,standardized and practical resistance identification method with stable pathogenicity for sugarcane white leaf disease(SCWL),and then promote resistance breeding.The resistance identification technology of SCWL was systematically investigated and explored from the aspects of treatment and planting of sugarcane varieties,inoculum preparation,inoculation method,disease investigation and formulation of grading standard.The simple and efficient,stable in pathogenicity,standardized and practical resistance identification method of SCWL namely seedcane-spraying inoculation method and stem-cutting inoculation method during growth period were optimized and established for the first time.The seedcane-spraying inoculation method was established on directly screening the sugarcane stem juice contained SCWL phytoplasma and adding 10-fold of sterile water to prepare the inoculum,spraying with the inoculum to the seedcane on the plastic film to keep moisture,planting the inoculated materials in the pot and cultivating in the insect-proof greenhouse,starting to investigate the disease incidence after 30 days of inoculation and planting,and evaluating the disease resistance according to the 1-5 grade standards.The stem-cutting inoculation method was established on directly screening the sugarcane stem juice contained SCWL phytoplasma and adding 10-fold of sterile water to prepare the inoculum,planting the tested materials in the pot and cultivating in the insect-proof greenhouse,using a pipette to drop 100μL inoculum into the cut section of the six month old stem,starting to investigate the disease incidence after 20 days of inoculation and planting,and evaluating the disease resistance according to the 1-5 grade standards.These two inoculation methods were similar to the natural transmission,and the incidence was obvious after inoculation,the sensitivity was high,the reproducibility was good,and the resistance identified result was consistent with the natural incidence in the field.Through two methods and natural disease investigation in the field,the SCWL resistance of 10 main cultivated varieties was identified,and their resistance was true and reliable,which could be used as the SCWL resistance identification standard varieties in the future.