甘南农牧过渡区燕麦田孢囊线虫的发生与分布

Occurrence and Distribution of Cyst Nematode in Oat Field in Gannan Agriculture-pasture Ecotone

为明确孢囊线虫在高寒、高海拔区的发生与分布情况,2015年8月,采用Z字型取样法,对甘南农牧过渡区10个乡镇燕麦田的80份根际土样进行了孢囊线虫调查。80份土样中孢囊线虫平均检出率为87.5%,夏河县的达菱乡、达麦乡、唐嘎尔乡与那吾乡,卓尼县杓哇乡及临潭县冶力关镇土样的检出率均达100%;夏河县王格尔塘镇最低,为60%。海拔高度不同,孢囊线虫的分布不同,在海拔2 501~2 800m的区域土样中,孢囊线虫检出率最高,为100%,在海拔3 101~3 500m区域检出率最低,为58.3%。燕麦田间孢囊线虫密度平均为3.7个·100g^(-1)土,其中卓尼县杓哇乡的密度最高,为14.4个·100g^(-1)土,夏河县王格尔塘镇和临潭县冶力关镇的最低,为1.1个·100g^(-1)土。通过形态学特征鉴定,此区的孢囊线虫为燕麦孢囊线虫(Heterodera avenae)。

In order to define the occurrence and distribution of cereal cyst nematode in cold, high alti- tude areas, investigations were carried out in August 2015 in oat fields of agriculture-pasture ecotone in Gannan by Z type sampling method. Eighty soil samples were collected in 10 towns and the average incidence of cysts was 87.5%. The highest incidence of cysts was found in towns of Daling, Damai, Tangger and Nawu in Xiahe county, Shaowa in Zhuoni county, and Yeliguan in Lintan county, with the incidence of 100%, and the lowest incidence of cysts was 60% in Wanggertang town. It was found that distributions of cereal cyst nematode were different at different altitudes. The highest incidence of cysts was found at the range of 2 501 to 2 800 m, with the incidence of 100% and the lowest incidence of cysts was found at the range of 3 101 to 3 500 m, with the incidence of 58.3%. The average density of cysts was 3. 7 per 100 g soil. The highest density was found in Shaowa town in Zhuoni county, with the average density of 14.4 per 100 g soil,and the lowest one was 1.1 per 100 g soil in Wangger- tang town of Xiahe county and in Yeliguan town of Lintan county. The populations of cereal cyst nematode collected in Gannan were identified as Heterodera avenae by observation and measurements of morphological characters.