青海东部农业区春小麦赤霉病初侵染来源的研究

连续3年对青海东部农业区6县小麦赤霉病发生的初侵染来源进行了系统研究,结果表明:青海东部农业区,小麦赤霉病初侵染来源因地理条件和种植作物种类不同而异。其主要来源可分为2种情况:民和、乐都县有玉米种植的部分乡镇,初侵染来源主要是玉米根茬和秸秆上产生的子囊壳和子囊孢子;其余各县(乡)赤霉病初侵染来源是麦茬、带病种子。不同作物根茬分离结果是:玉米根茬赤霉菌为禾谷镰孢菌FusariumgraminearumSchwabe],麦茬上分离到燕麦镰孢菌Fusariumavenaceum(Fr)Sacc]和锐顶镰孢菌(FusariumacuminatumElf.et.Ev),豌豆根茬上分离到三隔镰孢菌Fusariumtricinctum(Corda)sacc],油菜根茬上分离到燕麦镰菌Fusariumavenaceum(Pr.)Sacc],均属于小麦赤霉病的致病菌。回接试验证明,小麦穗部和根茬分离的赤霉菌及玉米根茬分离赤霉菌均可致病,而油菜、蚕豆根茬赤霉菌对小麦致病性弱或无致病性。

Studied on Primary Infection Source of Spring Wheat Scab in Eastern Agricultural Area of Qinghai Province

The primary infection source of spring wheat scab was continuously studied for three years in the eastern agricultural seven counties of Qinghai province. The results showed that primary infection source of wheat scab varied considerably in the geography condition and the species of planted crop. Its main source could be divided into two kinds of states: in partly villages and towns of Minghe and Ledu counties with corn planting, the sources mainly were the procreant perithecium and ascospore on the corn stubbles and ones stalks;in other each county, its source came from the wheat stubble and seed of vector. Results of isolation from different crops stubble were: Fusarium graminearum Schwabe (from the stubbles of corn), Fusarium avenaceum (Fr) Sacc and Fusarium acuminatum Elf.et.Ev (from wheat- stubbles), Fusarium tricinctum (Corda) sacc (on the pea-stubbles), and Fusarium avenaceum (Pr.) Sacc (on the rape- stubbles), all of these belonged to the pathogens of wheat scab. But the results of returning inoculation experiment showed that the Fusarium species were separated from corn root- stubble and wheat spike or wheat stubble all may cause this disease. But the Fusarium separated from rape or faba bean stubble had only feeble pathogenicity or had no pathogenicity to spring wheat.