橡胶籽苗黑根病病原鉴定及生物学特性研究

橡胶籽苗黑根病严重影响橡胶育苗生产,本研究从感病籽苗中分离病原菌,经致病性的测定,病原的形态特征观察和菌丝体的ITS、RPB2、tub2等基因序列分析对比,鉴定病原菌为球毛壳菌Chaetomium globosum;生物学特性研究结果表明,该菌生长适应能力强,在10~35℃、pH 2~10范围内菌丝和子囊孢子能生长和萌发,全光照能减缓菌丝的生长,糖类营养物质有利于子囊孢子萌发,子囊孢子较耐高温,48℃持续20 min,50℃持续15 min,52℃持续10 min,以及54℃持续5 min时才能导致病原子囊孢子失活、死亡。在夏季大棚不育苗期间,采用高温闷棚杀死病原孢子,必要时在育苗期结合化学药剂防治,对该病害可取得较好的控制效果。

Pathogen identification and biological characteristics of black root disease in rubber seedlings

Black root disease is a serious constraint for the production of rubber seedlings.Identification of the pathogen isolated from diseased seedlings and analysis of its biological characteristics would provide important information for management of black root disease of rubber seedlings.Through isolation of pathogen,pathogenicity test,morphological observation as well as comparison of RPB2,tub2 genes and ITS sequences,the causal agent for black root disease was finally identified as Chaetomium globosum.The analysis of its biological characteristics showed that C.globosum had a strong ability to adapt to the environment.The mycelia could grow well and ascospore under the culture temperatures of 10-35℃and pH values of 2-10.The successive lighting could slow down the growth of mycelia,and the carbohydrate nutrients were conducive to germination of ascospores.The ascospore could resist higher temperature,and the lethal temperature for pathogen ascospore was 48℃for 20 minutes,50℃for 15 minutes,52℃for 10 minutes,or 54℃for 5 minutes.The use of high temperature during the period without seedling cultivation in the greenhouse in summer could be an effective measure to kill pathogen,and application of fungicide could also achieve a better control effect for black root disease during rubber seedling raising.